Glue rollers should be hung up after use_Photo-engraving, Photo-etching and Photo-lithography in Line and Half-tone Also Collotype and Heliotype

being put away should be coated with fatty ink, and just before using

should be rolled clean upon a piece of rather fluffy paper; washing

glue rollers in turpentine is not to be recommended, as it tends to

harden them, and deprives them of their feeding quality. Glue rollers

can be bought ready cast, and it is advisable to so buy them; any

dealer in typographic material will supply them of a suitable quality,

if the purpose for which they are required be stated at the time of

ordering. The “durable” composition being very good for collographic

printing, it may be purchased and used for the rollers, for printing

from a heliotype skin, instead of the mixture given previously. For

roller No. 2, add two ounces of gelatine previously soaked in cold

water, and as much water squeezed out as is possible, then add this to

the “durable” composition, and stir until the gelatine is melted and

well incorporated with the composition.

These rollers may be cast upon the bare stock, without the India-rubber

sponge, if preferred, but the India-rubber sponge makes the roller much

lighter for use, which is a great consideration when long numbers are

printed straight away.

These remarks are applicable to the rollers used in the work described

in the previous chapters. Too much care cannot be given to the rollers.

The skilled printer who has feeling for his work will soon learn to

regard his rollers as the magic wands which produce his results. And

well he may.

The ink used for heliotype printing is the best chalk ink as purchased

in tins, brought to working consistency by mixing with lard, the two

ingredients being well mulled on the slab. Varnish must not be used,

lard being the best. Cocoanut and olive oil are also good. |156|

HELIOTYPE SKIN

is composed of a mixture of gelatine, glycerine, chrome alum,

bichromate of potash, and water, dried upon a slab of thick plate

glass. The surface of the plate glass must be very finely ground with

emery powder (great care being taken that there are no scratches or

holes, or they will spoil the skin), then thoroughly cleaned, and waxed

with a solution of beeswax in benzole, a good plan being to first

of all smear the glass with the wax, and then polish as much off as

possible with an old linen duster (clean), then sprinkle with clean

benzole, and with a fresh duster polish the plate thoroughly, noting

well that wax marks will spoil the skin.

This waxing need not be done every time a skin is made, but at

intervals of every three or four skins.

The waxed glass requires levelling, so that the gelatinous mixture

will set of an even thickness; therefore, a levelling stand must be

provided, as well as a good and true spirit level.

The gelatinous mixture is dried in an oven (see Drying Oven in chapter

on Collotype), at a temperature not exceeding 80° F., the time occupied

being from thirty to forty hours.

THE PEWTER PLATE.

The skin after exposure to light under the negative, etc., is mounted

by means of a squeegee upon a plate of pewter 21 by 15 by 1/8 of an

inch in thickness, and well polished. This plate is cleaned with

benzole and coated with a solution of India-rubber in benzole (well

filtered) and dried.

THE MASK.

To prevent the margin of paper upon which the ink picture is printed,

being dirtied, it is necessary, after rolling up, to lay a mask over

the skin, this mask having an opening in the centre the size of the

picture. Paper suitable for this purpose is made by coating bank-post

paper with a mixture of one part of gold size, and two parts boiled

oil; this mixture is laid on the paper evenly with a sponge, then hung

on a line to dry; when dry it is ready for use.

THE HELIOTYPE SKIN.

To prepare a skin 22 by 16, weigh out two ounces of a good gelatine,

and soak it in ten ounces of cold water until soft, then place it in

the porcelain |157| vessel of a “Bain Marie,” the outer vessel being

duly provided with the requisite quantity of cold water; now place it

over the fire or Bunsen burner, and stir until the gelatine is just

melted, then add two drachms of glycerine; stir well, so as to mix

thoroughly, and raise the temperature to 125° F.; add two ounces of

solution No. 1, and two drachms of solution No. 2; stir well, then

remove from the fire or Bunsen, and strain through muslin into a jug or

beaker; now tie over the jug or beaker a clean piece of muslin, when

the mixture is ready for pouring upon the ground side of thick plate

glass, waxed, properly levelled, and slightly warmed. Begin by pouring

in the centre of the plate, and gradually enlarge the circle until all

the gelatinous mixture is out of the jug or beaker, then with a strip

of clean card coax the gelatine to the edges.

Now examine the film for air bubbles, which, if present, must be

removed, either by pricking with a quill toothpick, or by coaxing to

the edge with a piece of card.

As soon as the mixture has thoroughly set (which it soon does), remove

it to the drying box.

Of course, the requisite quantity of gelatine for more than one skin

may be melted at once, but it will be better only to strain into

the pourer, from the “Bain Marie,” sufficient for one plate at a

time, remembering that the quantity now given is for one plate only;

therefore, if two, three, four, or more plates are to be dried at once,

the quantities given above must be increased accordingly.

The stock solutions named above are compounded as follows:

_No. 1._

Bichromate of Potash 1 ounce.

Water 20 ounces.

_No. 2._

Chrome Alum 1 ounce.

Water 20 ounces.

The temperature of the drying box must not exceed 80° F., and the time

occupied will be from thirty to forty hours, during the whole of which

time the temperature must be steadily maintained, but not exceeded.

When the skin is dry, with the point of a penknife separate the edges

from the glass, and then lift the skin away, when it is ready for

exposure to light under the negative. If it is desired to keep the

skins a few days before using, they may be stored between sheets of dry

brown paper in a drawer, or in a tin tube. |158|

It will be just as well to remark here that the dry heliotype skins

are sensitive to light; therefore, the drying oven must be in a room

illuminated by yellow light, or by artificial light, and the skins must

not be exposed to daylight until they are in the printing frame.

PRINTING THE PICTURE.

The heliotype skin is now ready for exposure under the negative, which

is done in a printing frame 24 by 18 inches, provided with a plate

glass front.

The negative must be reversed (_i. e._, instead of being taken direct

in the usual way, a reversing mirror is used). The margin of the

negative must be protected by a mask, with an opening cut the size and

shape of the intended picture, the outside edges of the mask being

sufficient to cover the rest of the skin.

To print, the back of the negative is cleaned, then laid with the film

uppermost, in the centre of the plate glass front of the printing

frame; the mask is then laid in position, the opening in the centre

being adjusted so that exactly the amount of picture required will

be printed upon the skin. The rest of the skin is protected from the

action of light by the opaque margin of the mask. Now lay the skin,

with the matt surface (_i. e._, the side that was in contact with the

ground side of the glass plate during the process of drying) next the

film of the negative; upon this lay a piece of dry black velvet, then

a sheet of thick felt, then the back of the printing frame, fasten up,

turn it over and see that the front of the glass is clean; then the

frame is ready for exposure to light.

EXPOSURE TO LIGHT

should be made in a good diffused light, and its duration timed by

means of an actinometer (see page 107).

As the time of exposure to light will vary according to the quality of

the negative, no precise rule can be made, the best way being to get a

small negative as near the same density as the other, cut off a piece

of the skin, and placing it in a frame, expose to light at the same

time as the big frame, and occasionally examine the progress of the

small strip of skin in the dark room. A very good idea of the exposure

of the big one can thus be had. A heliotype skin is properly printed as

soon as the details in the half-tones show themselves. Of course, it

should be understood that the small negative must be exposed to light

at the same time and place as the big one. |159|

SUNNING THE BACK OF THE SKIN.

The exposure to light under the negative being completed, remove the

skin from the printing frame, and lay it with the side that has just

been in contact with the film of the negative, upon a piece of black

velvet, covering the margin of the skin outside the picture with strips

of brown paper—these strips not quite touching the picture; now cut

off a strip of the skin, say a quarter inch wide by one inch long,

and double it lengthways, then cut a hole in a piece of brown paper

and place the doubled piece of skin under it. Now remove the skin to

diffused light, and as soon as the shape of the hole can be seen upon

the undermost half of the small strip, the sunning of the skin has gone

far enough, and it is ready for mounting upon the pewter plate.

The test here given for timing the sunning of the exposed skin is

suitable, when a good ordinary negative has been used, but if a

negative somewhat flat, or thin, has been used, then less sunning will

be required, and if a very intense negative, the time of sunning must

be increased, the object of the sunning being to reduce the relief

caused by deep shadows.

MOUNTING ON THE PEWTER PLATE.

The pewter plate upon which the exposed and sunned heliotype skin is

mounted for printing from, must be well polished, free from scratches

or other marks, the size being 21 by 15 by 1/8 of an inch in thickness.

This plate is polished with a soft duster, then coated with a solution

of India-rubber in benzole (about the consistency of sweet oil), the

solution being poured on, and flowed to the corners and edges; then the

plate is placed upon a levelling stand, and the India-rubber allowed to

dry.

This India-rubber solution is made by dissolving India-rubber solution,

as sold in tins at any India-rubber warehouse, in benzole or benzoline.

When the solution is made it must be filtered through paper, or

strained through five or six thicknesses of fine muslin, as the

presence of any grit between the surface of the pewter and the skin

would at once ruin the picture.

The India-rubber film being dry, place the pewter plate in a tray of

clean water, the water being about a quarter of an inch deep; now trim

the skin with a sharp pair of scissors to a little smaller than the

pewter (20-1/2 by 14-1/2), then lay the skin, face up, upon the surface

of water, and at once lift the pewter plate from the water, keeping

the skin in position by grasping the two top corners with the two

forefingers. Now lay the pewter on the bench, and |160| with a nice,

soft squeegee bring the skin into contact with the India-rubber film.

This mounting must be done rapidly, as if the skin gets a chance of

absorbing water it will frill, and be spoilt. The back merely requires

moistening, and the squeegee, in expelling the water, brings it into

contact with the India-rubber film. Now, with the squeegee, remove all

the water from the plate, and then brush round the edges with some

India-rubber solution, so as to reduce the chance of water, to be used

subsequently, from getting under the skin.

PRINTING FROM THE SKIN.

Now place the pewter on the bed of the press, and with a clean sponge

cover the picture with clean, cold water, in sufficient quantity to

form a pool about one-eighth of an inch deep, care being taken that the

water does not extend as far as the edges of the skin.

The water is allowed to remain on the skin for five minutes; it is then

soaked up, and a fresh supply added, and this operation is repeated

at intervals for twenty or thirty minutes, the object being to partly

remove the bichromate, and also to allow the gelatine that has not been

rendered insoluble by the action of light, to absorb sufficient water

to enable it to repel the ink from the roller.

When it is judged that the image has been sufficiently soaked, with

the sponge remove as much water as possible, then lay a clean sheet of

paper upon the skin; upon the paper lay the loose blanket, lower the

tympan, run the bed of the press under the platen, then pull over the

lever, and subject to as much pressure as the press will give, allowing

the pressure to “dwell” for a minute or two.

This is to “smash” down the highest relief in the skin, which, unless

so smashed down, would interfere with the roller feeding the ink in the

deepest shadows.

The skin is now ready for inking up with No. 1 roller, charged with

the best litho. ink mixed with a little lard, just sufficient, and no

more, to make the stiff ink distribute on the slab, the ink and the

lard being thoroughly incorporated, either with a stiff palette knife

or with a muller. The ink and lard being thus well mixed upon the slab,

gather up the compound and place it in one corner of the slab.

For No. 2 roller take a portion of the above mixture and add to it a

little more lard, and mix well, then place this in one corner of the

other inking slab.

With the palette knife touch the roller No. 1 at short intervals with

little dabs of the first ink, then roll it vigorously on the slab up

and down, and then |161| across and sideways, until the ink is evenly

distributed over the roller and the slab; now with the roller proceed

to ink up the image. Use plenty of pressure, and turn the roller first

one way, then the other, until the image shows itself vigorous and

strong.

Now take No. 2 roller charged (in the same way as No. 1) with No. 2 ink

well distributed (but do not use quite so much as with No. 1), and with

a light pressure go over the inked image; this inking will fill up the

light half-tones and clean up the image generally.

Before pulling an impression take a sheet of mask paper (which must be

a little larger than the pewter plate), and in the centre cut a clean,

sharp opening the size the picture must be. This mask, with the oiled

side down, is adjusted in position on the skin; then turn back the edge

furthest from the operator, and upon the extreme edge of the pewter

place a few small dabs of stiff ink, return the margin of the mask over

these dabs of ink, and rub down; these dabs of ink serve to keep the

mask in position, when turned back for each inking up. If the margin of

the mask paper projects over the pewter plate, and outside the bed of

the press, it must be turned down, else it will tear when the bed of

the press is run in.

The mask being laid in position to protect the margin of the print,

lay a piece of matt enamel paper on the inked up and masked image,

back this first with a sheet or two of clean blotting paper, then with

a loose blanket; lower the tympan, and run the bed of the press under

the platen and pull over the lever. The pressure requisite to pull

an impression from a heliotype skin requires the full strength of an

ordinary man to pull over the lever.

Now examine the print, and if it is flat and dirty, the skin has not

been soaked sufficiently before inking up, so remove the ink left by

the paper by washing it over with a rag soaked in turpentine, then wash

with a wet sponge, blot off the surplus and with the sponge again put

a pool of water over the image, and allow it to soak for about five

minutes; again wipe it off with a sponge, smash down and ink up again.

If the image is black and white without half-tones, the fault may lie

in the negative, which perhaps is too hard; or if that is all right,

then the skin has not been sufficiently exposed in the printing frame,

in which case it may be at once thrown away, as no amount of coaxing

will make it yield a good print. Or it may be that the skin is too

damp, in which case rub it gently with the water sponge, on which a few

drops of alcohol have been sprinkled; then blot off, ink up again, and

pull another proof. |162|

If the back of the skin is “sunned” too much, the print will suffer by

being dirty and flat, and will require sponging over with a little of

the ten per cent. mixture of ammonia in water; then blot off, and again

ink up; take care and keep the ammonia sponges away from the other

sponges.

If the deep shadows show a white margin and are difficult to ink up,

the skin has been exposed under the negative for too long a time; and

if “smashing” down does not remedy the defect, the only chance of

saving it will be to allow the skin to get thoroughly dry, and then

(say the next day) to soak it up again for an hour.

Spots on the margin of the print may be removed by carefully painting

them over with a camel’s-hair brush charged with dilute cyanide of

potassium, carefully washing afterward to prevent spreading.

Each time the image is inked up, the mask must be laid back, so as not

to interfere with the roller; then after inking up, it is again laid in

position, so as to protect the margin of the paper upon which the print

is made.

It must be borne in mind that the first print from the skin will not

be the best it is capable of giving, therefore, before any of the

above-named dodges are resorted to, the image should be inked up and

proofs pulled four or five times; as a generul rule perfection will not

be attained until about ten or twelve prints are made, using each time

a good paper, as a soft spongy one will not pick up the ink on the skin.

Of course, a plain black ink will not suit every class of subject,

therefore, when the operator requires a different tint or color, it

must be made by a judicious blending of stiff ink of the proper colors

mixed with lard as given above. When a distinct change of color is

required, it is not a good plan to wash No. 1 roller, but have a

separate No. 1 roller for each color. No. 2 roller may be washed for

such a purpose.

If it is desired to print two tints, the darkest tint is applied with

the No. 1 roller, the lightest with the No. 2 roller.

|163|

CHAPTER III.

THE COLLOTYPE PROCESS.

This process, roughly described, consists in carefully grinding with

fine emery, a plate of thick glass, then coating it with a mixture of

white of egg, or of stale beer and silicate of soda. After the plate is

dried it is rinsed in water, and dried again, then warmed, and coated

with a thin film of bichromated gelatine. This coating is then dried

in a suitable oven, after which the plate is exposed to light under a

reversed negative, followed by a short exposure of the back of the film

to light, then washed in cold water until the whole of the bichromate

is removed from the film, when the plate is allowed to dry. It is next

soaked in cold water, then in a mixture of glycerine and water, after

which it is placed upon the press, and the printing proceeded with.

As in lithographic printing, the size of the paper upon which the

picture is printed determines the size of the stone upon which the

transfer is made, so as to give a good margin, not only large enough

to prevent the paper being marked by the edge of the stone, but also

to allow plenty of room for working the roller; so in collographic

printing, the glass plate upon which the picture is to be made must

be sufficiently large to allow a margin of _at least_ four inches all

round the outside of the picture. This is not only requisite for the

reasons that hold good in litho. printing, but for the additional one

of giving plenty of room for the manipulation of the mask used to

protect the margin of the print.

Collographic plates should also be sufficiently large to prevent their

edges from cutting the composition rollers used for inking the image;

for instance, a roller nine inches long should never be used upon a

plate less than twelve inches wide.

Collographic films are made upon good patent plate-glass half an inch

thick, free from scratches, with the edges nicely bevelled to avoid

cutting the rollers; this bevelling the plates is absolutely necessary

for use upon the machine, but is not so important for the hand press.

To prepare plates for use they are first ground with fine emery powder.

To do this place one plate upon a smooth board or a couple of bearers

across the sink, sprinkle with fine emery powder (sifted through book

muslin), then with |164| water. Now, with another plate on the top,

proceed to grind with a circular motion, continuing the grinding until

the emery is worn smooth; then renew the supply of emery, sprinkle with

water and again grind until the emery is smooth; now work well with

water, squeegee dry, and examine the surface; if it is evenly ground

the plates are ready for the next stage. If they are not ground all

over, cover them again with emery and water, and continue to grind

until the surfaces are of an even matt all over.

The plates being ground, they are well rinsed under the tap, and both

sides are well rubbed with a rag to free them from all particles of

grit, etc., then flood them with a mixture of

Liquor Ammonia 1 ounce.

Alcohol 1 ounce.

Water 5 ounces.

rub this well in with a clean rag, and again well wash with clean

water, then allow to drain and flood with

THE PRELIMINARY COATING OF

Stale Beer 5 ounces.

Water 5 ounces.

Silicate of Soda (Waterglass) 2 ounces.

made up an hour or two before using, and filtered.

The wet plate is covered with this two or three times, and then placed

on a rack to dry. When all the plates in the batch are coated the rack

should be removed to the drying oven and the plates dried _in sitû_,

not lying down.

Be as careful as possible to prevent any of the beer and silicate

mixture from getting on the back of the plate, as it interferes with

the running of the image afterward.

Plates may be prepared with the preliminary coating in quantity, as the

coating hardens and improves by being kept.

When the coating on the plates is quite dry rinse them under the tap

and again dry them, this time quite spontaneously. Lastly, they are

placed upon the slab of the drying oven to get sufficiently warm before

being coated with the sensitive mixture.

The sensitive mixture must be made exactly as follows, as everything

depends upon the time and temperatures named: First of all, take thirty

ounces of pure water and add ten drops of a saturated solution of

chrome alum; shake up well and allow to stand ten minutes; if the water

is very slightly opalescent, it is |165| quite satisfactory, but if

there is any tinge of green then too much chrome alum has been used,

and it must be thrown away and another lot made.

Then add two and one-half ounces of fine gelatine and allow it to

soak until soft, then place it in the “Baine Maire” and melt the

gelatine, stirring all the time. Raise the temperature to 125° F. and

keep it thus for fifteen minutes; next add 150 grains of bichromate

of potassium in fine powder, stirring until dissolved, and raise

the temperature to 150° F. Strain the mixture through muslin into a

porcelain jar and allow it to cool, keeping it in jelly at least twelve

hours before using it.

This sensitive mixture does not work well if used to coat plates

with directly it is made; therefore, it must be made up some time in

advance. It keeps well, in fact improves, with keeping, up to about

seven days. In remelting for use, only melt just sufficient for the

plates to be coated, as it does not improve it to melt it too often.

Plates coated with the above mixture are dried at a temperature of from

100° to 120° F. in from two hours to three hours, and have a splendid

grain.

Here is another formula the mixture from which does not keep, but

must be made and used directly. It is the formula most frequently

used by the writer. Plates prepared with it can be dried, at lower

temperatures, in from twenty to fifty minutes. It is also the best

formula when copper plates are used instead of glass, of which mention

will be made at the end of the chapter.

Soak two and one-half ounces of gelatine in fifteen ounces of water

until quite soft, then place all in the “Baine Maire” and melt at as

low a temperature as possible; when melted add 100 grains of bichromate

of potash and 50 grains of bichromate of ammonia both in fine powder,

stirring until dissolved; now put in the thermometer, and raise the

temperature to 140° F. and keep it there for ten minutes; then allow

to cool to 125° F. and add the following mixture, stirring vigorously

the while: fifteen ounces of alcohol and five ounces of a saturated

solution of borax in alcohol. Mix the two before pouring them into

the hot gelatine. With some gelatines the addition of this mixture

will cause a slight coagulation of the gelatine, and it will stick to

the stirring rod; therefore, the solution must be stirred until the

coagulated gelatine is redissolved; then strain it through muslin into

the pourer and at once use it by pouring it over the warm plates.

One of the best vessels to use as a pourer is an invalid’s cup with a

spout at the side.

The above quantity of mixture is sufficient for sixteen plates 16 ×

13 inches; |166| therefore, if only four are to be coated, which is

the quantity that the drying oven to be described will take, the above

quantities must be divided by four.

Now if the first formula be used, take sufficient of the jelly,

melt it and strain it through muslin; then take one of the plates

from the drying oven—which plate should be just warm enough to be

comfortably held on the palm of the hand—carefully brush it over with

a dusting-brush, so as to remove any particles of dust that may have

adhered and balancing the plate on the palm of the hand, pour over it

sufficient of the warm gelatine to just cover it. A 16 × 13 plate will

take a little less than two ounces of the gelatine mixture. Take care

not to spill any. Next place the plate upon the hot slab, and coat the

rest in the same way. When all are done close the door of the oven and

do not open it again until the plates are dry.

With the second formula the _modus operandi_ is the same, except, of

course, that instead of melting the already made jelly, the mixture

made as above directed is used directly after mixing. The plates being

dry they are ready for exposure, which need not necessarily take place

at once, as if stored away in the dark and away from damp they will

keep two or three weeks.

The exposure to light is made in a box-pattern frame, the negative

having a mask in front of it to protect the margin of the plate from

the light.

The negative used must be reversed—_i. e._, the image must be in its

right position on the negative when viewed through the film, not as

ordinary negatives are—through the glass; therefore, a mirror must be

used in making the negative, or a skin negative may be used; or, if

neither is practicable, the negative must be reproduced by one of the

methods already given.

The exposure to light in the printing frame will vary according to the

density of the negative, and the strength of the light, and should be

continued until the image can be seen well defined upon the gelatine

film when examined in the dark-room, by opening one-half of the back of

the frame.

The exposure being complete, lay the printing frame face down upon a

table in the light, remove the back and packing, and expose the back of

the film to the light for a short time, without in any way disturbing

the position of the collotype plate or the negative.

This exposure of the back of the image to the light has a twofold

advantage, one being that it helps to weld the sensitized gelatine film

to the surface of the plate, and so enables it to stand the wear and

tear of printing; the other, that it reduces the relief of the picture,

and so gives the inking roller a better chance of feeding the deep

shadows. |167|

The duration of the exposure of the back of the film to the light will

vary very much with the subject in hand; if it be one with slight

contrasts, a much shorter time will be required than where the picture

contains a lot of very heavy shadows.

The next step will be to remove the plate from the printing frame, and

immerse it in clean cold water for five or six hours, or for such a

time as suffices to remove the whole of the bichromate from the film.

The plate is then placed in the rack to dry spontaneously, and should

be allowed to stand for at least twelve hours afterward before printing

from, so as to give the film a proper chance to become thoroughly hard.

We now have a collotype plate which has undergone the following

operations, viz.:

A plate of thick glass ground with fine emery until of an even matt

surface. Then it is washed and coated with the preliminary coating of

beer and silicate of soda and dried. Then rinsed in cold water and

again dried. Next placed on the warm slab of the drying oven until just

warm enough to hold on the palm of hand. Then coated with the sensitive

mixture, either No. 1 or No. 2, and placed in the oven until dried.

Then exposed to the light under a reversed negative in a printing frame

until the details of the image are well out. Then the back of the plate

is exposed to the light for a short time. Then it is placed in clean

cold water until the bichromate is removed. At last the plate is dried,

after which it is ready for the printer.

[Illustration: Fig. 17.]

Now, before proceeding further, it will be as well to touch upon

various points of procedure, and also to describe what may be reckoned

the most important piece of a collotype plant, viz., the drying oven.

Figure 17 gives a drawing of the oven as it stands on the table for

use, the |168| dimensions being from the top to the bottom of the

frame 5 feet by 3 feet 4 inches wide by 3 feet deep. The top A, and

the back, are covered with matched boards well seasoned; the sides

and front, B, B, B, B, are made of frames 2 inches by 1 inch, covered

with canvas sufficiently close to exclude light, but still open enough

to let out the heat slowly. The door C is also a frame covered with

canvas, 24 inches square, sliding upward in grooves, and balanced

by means of weights. D is the jacket of iron upon which a copper

tank rests, the jacket serving to carry the tank and to protect the

wood-work from the gas flame used to warm the water in the tank. E is a

sliding door in the jacket for the purpose of lighting the gas burner.

F F are the projecting ends of a levelling arrangement forming the base

of the oven, these ends being fitted with good, strong screws working

upon iron plates let into the top of a strong table upon which the oven

is placed. The distance between the two lower rails or styles is 6

inches, which is also the height of the iron jacket. D G is a tube let

into the jacket to carry off the products of combustion from the gas. H

is a tube with a screw nozzle, for filling the tank.

[Illustration: Fig. 18.]

[Illustration: Fig. 19.]

[Illustration: Fig. 20.]

Figure 18 is the base of the oven, _A A A_ being the three points where

the levelling screws are placed; this base is formed of good 4 by 3

inch quartering, the other dimensions being as marked. This base stands

on the table, the oven on the top, without any fastenings. |169|

Figure 19, the jacket of sheet iron well wired, with a tube at one

corner, for carrying off the products of the combustion of the gas, and

a hole at the other corner to carry the projecting tube from the tank,

by which it is filled.

Figure 20, the copper tank, the outside dimensions of which are 37 by

31 inches, the flange fitting on top of the jacket; the depth of the

tank in the centre is 3 inches; the inlet pipe is 1 inch bore, and 6

inches long, the bend being taken high enough to be about 2 inches

above the top of the tank.

The base is placed upon the table, then the iron jacket on the top of

the base; then the copper tank is fitted into the top of the jacket;

upon the top of the tank is placed a slab of marble or slate 37-1/2 by

31-1/2 inches, cemented by means of plaster-of-Paris. The wooden top of

the oven is fitted into position, the canvas being nailed on last. But,

before doing this, it will be as well to fix the bearers as at C C C,

Fig. 21, with corresponding ones on the other side, so that slats may

be placed across for the purpose of holding heliotype plates, and for

drying transfer paper, etc. The interstices between the edges of the

slab and woodwork should be made good, either by means of wooden laths

or cement.

[Illustration: Fig. 21.]

The oven being erected, the first thing to do will be to fill the

copper tank with water; then level the slab by means of the screws, or

if the bottom ends of the base are shod with sheet iron, wedges may be

used to level with. The drying oven must be kept in a room at a uniform

temperature of about 60° F.

In using the oven after the plates are dry (after rinsing), place a

piece of clean, dry, brown paper upon the slab, then place on this

paper four plates 16 by 13 inches—which are the size and quantity for

which the dimensions of the oven have been calculated; then place a

thermometer between the plates, and close the oven. After the water has

been brought to boil, the plates will be ready for coating; but, if the

thermometer registers over 120°, turn off the gas, coat the plates,

again close the door, and let the plates dry.

One of the first things the student must do is to familiarize himself

with the oven. Note the time taken to bring the water to boil; the

temperature of the |170| slab, and the time taken for the temperature

to fall after turning off the gas. A day spent at this will teach far

more than it is possible to do by writing.

Do not try to improve the oven by having the door to open any other way

than by sliding. If made to open in or out, a draught of air is created

which will cause mischief. Petroleum, instead of gas, may be used for

heating the water.

Instead of using glass plates for carrying the collotype film, copper

or brass plates may be used. They should be grained with fine sifted

graining sand and a stone muller, then washed with plenty of fresh

water, and coated with

Stale Beer 5 ounces.

Water 5 ounces.

Silicate of Soda (syrup) 2 ounces.

Tannin 1 grain.

Prepare the mixture three or four hours before using, and filter it

carefully. The subsequent operations are the same as with glass, except

that the sunning of the back of the film must be dispensed with, and

the second formula for the bichromated gelatine mixture must be used,

as the first one gives too high a relief for copper.

Plates that have been used are cleaned again for further trial, by

immersing them in a pickle of American potash or concentrated lye, then

well washing, regrinding, washing, and finally coating with the beer

and water-glass substratum, exactly as before mentioned.

|171|

CHAPTER IV.

PRINTING FROM THE COLLOTYPE PLATE.

Collotype plates are usually printed from, upon a typographic press,

but the best press is one with a cylinder, like the lithographic

machines. Such presses give a more even pressure, and at the same time

will enable more impressions to be made in a given time.

In the chapter on heliotype printing, a description is given for

preparing the tympan for printing from the heliotype skin, and that

description holds good for collotype plates; but we shall require a

slate slab, the full size of the bed of the press, and a little under

half an inch in thickness, upon which to fix the collotype plate by

means of plaster of Paris.

The press being ready, take the dried plate, and soak it for half an

hour in clean cold water. After that wipe it with a clean soft rag, and

scrape any gelatine from the back that may have found its way there;

spread as evenly as possible some fine plaster of Paris over the slate

slab on the bed of the press, then damp with sufficient water to make

the plaster the consistency of cream, and lay the damp collotype plate

in the centre, and press it well down, working it a little so as to

get it level and well bedded in; allow the plaster to form a ridge all

round the edges outside the plate, levelling these ridges by running

the finger over the moist plaster, so that they do not project above

the face of the plate. Now cover the collotype plate with a mixture of

Glycerine 5 ounces.

Water 10 ounces.

Ox-gall a little.

Allow this fifteen minutes to permeate the film, taking care that it

covers the whole of the surface evenly.

Whilst the plate is thus soaking up, get the inking slab clean, and the

two rollers ready, viz.: An ordinary lithographic roller, for inking up

the heavier portion of the image, and a composition roller for inking

the half-tones and clearing the image; then mix the ink to the desired

shade by taking some stiff ink from the tin, and mixing to the proper

consistency with a little olive oil. The ink must not be made thin, but

just sufficiently softened to work up with |172| the palette knife.

The ink used must be very finely ground by machinery with a minimum of

olive oil. This, in hand grinding, is difficult to do, and the presence

of too much varnish in the ink is prejudicial to the production of

bright collotype prints.

The ink being mixed, a little is taken up on the point of a palette

knife and smeared along the face of the leather roller and then

worked vigorously upon the inking slab, until the ink is thoroughly

distributed upon both roller and slab. Do not attempt to thin the

ink so as to lessen the labor of distributing the ink, as that will

only render the collotype print flat and weak. The ink must be stiff

and spare. Now remove the soaking fluid with a very soft sponge, and

blot off with fine plate paper, then proceed to roll up with the

leather roller, until the image just shows nicely on the plate. Do not

attempt to get it to take sufficient ink to look black. Next take the

composition roller, and a little ink thinned with lard to about half

the consistency of that used with the leather roller, and touch it

here and there with the palette knife holding this thinner ink, and

roll up on another slab until the ink on the slab and roller are quite

even; now apply the composition roller to the image inked up by the

leather roller, and roll with a light pressure and quick motion. This

will complete the inking up of the image. Now take a piece of the mask

paper mentioned for heliotype printing, and having cut out a suitable

aperture, place it in position upon the plate, then put a piece of

paper in position upon the mask; upon this paper fix a large sheet of

smooth waste paper, then loose the blanket, lower the tympan, run the

bed of the press under the platen, and after adjusting the pressure,

pull over the lever, run out the bed, and examine the proof. From that

deduce whether the ink is too thin, or too thick, or not enough, or too

much. Damp with a sponge dipped in water, then blot off or remove the

surface water with a damp soft rag, then ink up again, and repeat until

a suitable print is the result.

Some collotype blocks require the ink far thinner than others,

therefore it will be the aim of the printer to try various degrees of

ink with each plate until the best result is attained. The best prints

are got, as a rule, from a roller that seems to have very little ink

upon it, but the ink thoroughly well distributed over both slab and

roller.

To print from a collotype plate it is necessary that those portions

of the film which have not been exposed to the light—and from them in

proportion as the gradation of tone progresses to the shadows—must be

charged with moisture to enable them to resist the greasy ink; if plain

water be used for this it would |173| be troublesome to get sufficient

in the film to resist the ink, and at the same time enable the roller

to feed the image without slipping. Therefore glycerine is used, mixed

with water, and with various hygroscopic substances, to which the term

“etching fluids” has been given. This term is a misnomer, and quite out

of place, “damping fluids” being the best.

In addition to the damping fluid previously given, a few others are

here appended, each having their advantages under certain conditions:

Glycerine alone or with water.

or,

Glycerine 5 ounces.

Water 5 ounces.

Hyposulphite of Soda 1/2 drachm.

or,

Glycerine 5 ounces.

Water 5 ounces.

Nitrate of Potash 1 drachm.

or,

Glycerine 5 ounces.

Water 5 ounces.

Ammonia 10 drops.

or,

Glycerine 5 ounces.

Water 5 ounces.

Common Salt 30 grains.

or,

Glycerine 5 ounces.

Water 5 ounces.

Chloride of Lime 1 drachm.

The last one must only be used when it is desired to take away a

tint, and if used too often, will be very likely to destroy the image

altogether.

During the printing from a collotype block, the number of impressions

that may be pulled without redamping, will vary very much with each

block. Sometimes as many as eight or ten may be pulled, but the average

will not exceed two. As soon as there is a tendency to flatness, take

a sponge containing a little of the damping fluid, and go over the

film with it, then wipe it off |174| with another sponge, or a piece

of damp cloth (soft), then blot it off with a piece of good blotting

paper, and ink up again. In fact, as a rule, it is best to damp for

each print.

Good printing paper must be used for collotype prints, and for very

fine work a fine neat enamel paper will be best. Coarse hand-made

papers, however much admired, must soon break up the delicate image.

[Illustration: Fig. 22.]

I will describe another drying oven, the heating arrangement of which

is the same as the other, but the superstructure is much smaller. It

will require more care during the time the coated plates are drying

to keep the temperature down, but it has the advantage of allowing a

thermometer being inserted in the lid in such a manner as to allow

the temperature of the interior being seen at a glance. Still another

advantage is, it takes up much less room. It measures inside 18 inches

wide by 32 inches long, and 9 inches deep to the top of the slab. The

thickness of the slate slab and of the copper tank should be the same

as in the larger oven; the lid at the top should be made solid and have

an orifice in the centre through which the thermometer is pushed. The

sides of the oven should be covered with one or two thicknesses of good

red flannel.

The only thing that calls for particular attention in these ovens is

the copper tank, which should (especially the top) be made of good,

stout sheet copper, otherwise the water on being heated has a tendency

to make the copper bulge, and elevate the slab. By that means the care

which should be taken in levelling the slab will be lost, as this

elevation will put it all out. Before putting the superstructure in

position, the slab must be cemented to the top of the copper tank by

means of plaster-of-Paris; this is important, as a much more even heat

is thus obtained.

Now, whichever oven is decided upon, it must be erected in a room free

from draught, where it can be kept at a temperature of 70° F., as the

quality of the collotype plate is much influenced by the temperature of

the room in which it is prepared. So, too, is the oven in which it is

dried, especially if below 60°, for then it is very difficult to get

good results, as the plate chills when taken from the oven, and the

film is almost sure to prove rotten during the printing. |175|

In the summer time, if the room gets too hot, the gelatine solution is

apt to get frothy, and then dry hard and glossy, instead of with a nice

half-mat surface. It is then best to prepare the plates only in the

early morning.

The temperature at which to dry the collotype plates will vary

according to the subject to be printed upon them, as some subjects will

require a finer grain than others. But a few intelligent experiments

will soon enable the operator to judge of the temperature required;

75° F. is the lowest, and 120° F. the highest temperature giving good,

bright blacks.

One of the great secrets in collotype is to give a double coating to

the plate. I find it really a great advantage so to do. I found this

out quite by accident. One day, when I went to use some plates, I

found that they had not been properly levelled, and that the coating

was thin at one end, and thick at the other. This happened to three

out of a batch of four, the other one being all right; so, in a fit of

laziness, or hurry, or something, I decided on recoating the three, and

did so. When I came to print from the three twice coated and the one

once coated, I was agreeably surprised at the difference; the pictures

on those twice coated were much more vigorous. Since then I have tried

the experiment exactly, and always get the same uniformly excellent

results. The second coating is applied as soon as the first is dry;

but this second coat cannot be applied so well if the plate be held on

the hand, therefore a levelling stand should be used, and the gelatine

poured on the centre and coated over the surface by means of a glass

rod.

The proper quantity of gelatine solution requisite for a plate 16 by 13

inches is 2 ounces for each coat. Note well that all of it is left on

the surface of the plate, not some on the table.

When once the coated plates have been placed in the oven, and the

lid is closed down, they must not be disturbed until they are dry;

this will be in two or three hours, according to the thickness of the

coating of gelatine. If removed before they are dry, there is danger of

marking the film.

After the second coating of gelatine is dried, the plate will be all

the better if kept a few hours before being printed upon, care being

taken to store it in the dark, or somewhere free from damp and gas

fumes.

By the bye, the oven must be placed in a room illuminated by yellow

light—_i. e._, daylight filtered through yellow glass, cloth, or paper;

or else the room must be lighted by gas or oil light.

The negative to be printed from should have all the parts that are

intended |176| to be quite white in the finished print, stopped out

with India ink or Gihon’s opaque, and the limit of the picture should

be masked by very thin tinfoil, cut quite straight and gummed upon the

film side of the negative. The rest of the margin of the plate must be

protected by a brown paper mask.

The best printing frames for collotype printing are of the box (or

“deep”) pattern, with plate glass fronts. They should be about two

inches deep, and the bars behind quite plain—_i. e._, without either

screws or springs. The back board should also be dispensed with, the

pressure being got by means of wedges. The advantage of these frames is

that the picture can be examined without undoing the back, and without

risk of shifting the plates.

After printing, the plate should be placed in a zinc vessel like

a plate box fitted with a siphon, so that the water can be kept

constantly changed, until the bichromate is removed; then the plate is

drained, and, after being wiped with a soft cloth, is put away to dry.

Now then, beginners, do not be in a hurry to try your first plate on

the press directly it is free from the bichromate, as no plate will

give a good result until it has been dried down. Before putting it on

the press, soak it for half an hour in water, then half an hour in

glycerine and water in equal parts, and, finally, wipe it, and proceed

to ink up the press.

The safest plan is the one mentioned, viz., bedding up slate with

plaster-of-Paris. Another plan is to place on the iron bed of the press

a piece of thin felt, then a slab of glass, upon which are placed two

thicknesses of wet blotting-paper; upon these place the collotype plate

(the back of which is free from any gelatine that may have run over

after coating); then, if a chase be placed on the press, the plate may

be blocked in position by means of a few pieces of furniture tightened

by means of quoins.

In the above only glass slabs are treated of; but brass plates, about

one-eighth of an inch thick, will be found safer, and more economical

than glass, and yield results just as good. They may be fixed upon a

block of hard wood by means of a screw (countersunk) at each corner. If

an ordinary type press is not at hand, brass plates may be printed from

upon a litho. press.

Whether the plate will require damping each time will depend greatly

upon each individual plate and the subject. With some, damping must

be done each time; with others, once only for four, six, up to a

dozen pulls; but, of course, the temperature of the room in which the

printing is conducted will be an important factor in determining this

point. When the print is flat, and the whites degraded, then damp the

plate before again inking up. |177|

To insure even prints, care must be taken to keep the roller well

charged with ink. Much more could be written on this subject, but

practice will be the best guide.

A word as to bedding the glass slab on. With a properly prepared

leather litho. roller, charged with ink mixed with a little olive oil

and varnish, brought to a working consistency with a muller on a smooth

slab (be sure that the ink on the roller is evenly distributed), after

wiping the plate carefully with a soft, damp cloth, proceed to ink up

the image slowly and carefully; then, when all the ink possible has

adhered to the image, take the glue roller and apply it three or four

times, which will clear the image wonderfully. Now put the mask in

position—either a cut-out, or four narrow strips of bank-post coated

with gold size and oil, and then dried—then put a piece of mat enamel

paper in position, then a piece of common printing paper on top, then a

piece of blanket; lower the tympan, run in the bed, and press, and, if

the pressure is not too much, the prints will be just as good; but, if

too much pressure be used, the paper will be creased and spoiled, and

the collotype image is in danger of being cut.

|178|

CHAPTER V.

THE NEW HOME PRINTING PROCESS.

There is a method of making reproductions from photographs without any

photographing process further than that required to supply the print.

Any good photograph with a matt surface may be traced over with the

ink supplied for the purpose by the inventor of the process, or with

the ordinary lithographic autographic ink, which comes in sticks like

India-ink, and then the superfluous portions faded away (or not) as

directed on a preceding page. From that or from a crayon sketch, music,

a written letter, plans, or circulars, in fact, from anything written

with the proper ink with a pen or printed, reproductions may be made.

The principal appliances needed are the “Universal Copying Machine” and

its accessories.

[Illustration: Fig. 23.]

Where the results desired need not be of as high a grade as those made

by the Collotype processes, or where there is not time to make a zinc

etching, this method will serve a good purpose and produce satisfactory

results. The zinc plates used for etching will serve to hold the

transfers. The methods for cleaning the plates, already given, will

serve here also. The machine should be securely fastened to a table and

_the bearings must be kept well oiled_.

Write, draw, or trace the original with a steel pen and the ink, on

well calendered paper, not too thick. For drawing, a fine pen is the

best. Then lay it, written side up, in a shallow dish, cover the paper

with the transfer solution, leave it from four to five minutes. If the

writing is several days old, leave it longer—about ten minutes. Lay it

between blotting paper and dry gently by rubbing with the hand or a

cloth. Then lay it, written side down, upon the polished plate, pass

it from four to six times under the iron roller, having first placed

a pasteboard over it. To prevent slipping, it is well to cover the

original with a sheet of blotting paper before putting the pasteboard

|179| over it. If you are not sure your press is screwed up evenly,

run the plate through two or three times, then turn it end for end and

pass it through as many times the other way.

[Illustration]

Place upon the small distributing roller as much printer’s ink as will

go upon the point of a knife, then holding the handle with the left

hand, press it upon the inking roller, and turn the crank, moving

the distributing roller from side to side, until the ink is evenly

distributed.

See that the rollers are an equal distance apart at each end, so as to

print evenly. The original is now carefully removed.

After washing the plate gently with a sponge and water and drying it,

also gently, with a clean cloth, rub the whole printed or written side

of the plate, by means of a cloth or sponge, with mixture No. 1, not

pouring the mixture directly upon the writing, but upon an unprinted

place upon the surface and rubbing over the whole plate. Wash off

immediately with sponge and water, and dry gently; then pour about

twenty drops of No. 2 upon the plate, not directly upon the print, and

rub over the whole surface, so that there is a thin coating of it over

the whole surface. This prevents the ink from sticking to the part of

the plate not covered with writing or print. If there is too much, the

paper of the copies will be yellow, and the negative may be injured.

Now lay the plate upon the pasteboard and pass it under the inking

roller (the pressure does not need to be strong); it falls before

the iron roller; place a sheet of clean paper upon the negative, lay

a pasteboard over it, and pass it under the roller. For the first

impression it is well to pass it under several times, until the

negative comes out clearly and distinctly. From time to time, after

every ten or twelve impressions, apply No. 2; if the paper used for

printing is very coarse or porous, it may be necessary to apply No. 2

oftener.

As soon as the impressions become faint, apply a little more ink in the

manner described. After applying fresh ink, apply No. 2. Only when too

much ink is put on or unevenly distributed, or when the plate is not

covered with the thin coating of No. 2, or not properly cleaned, can

the negative or plate become soiled. If this should happen from any of

these causes, remove the spots carefully by means of a cloth wet with

preparation No. 2.

If the ink hardens on the rollers remove it with lye or washing soda.

If you wish to interrupt the work, the plate must be washed with a wet

sponge, to remove the preparation, and then dried with a cloth. On

using again, apply No. 2, as before. If the plate has not been used for

several days, apply both No. 1 and No. 2. Do not use woollen cloths.

The mixtures No. 1 and No. 2 are supplied with the press. |180|

Thus it will be seen that photographs may be reproduced by many

processes and in quantities to accommodate all sorts of demands. As an

averment of what the future holds, our book is brought to a close by

the following quotation from a recent issue of a daily newspaper:

“Some time ago the _Evening Post_ gave an account of a new process

by which books were being reproduced in this country directly from

photographic plates, and it was said that the field for such business

would probably grow in proportion to the ease and certainty with which

this kind of work could be done. Under this process the most important

work issued so far has been seventeen volumes of the _Encyclopædia

Britannica_, this production being sold at half the price asked for an

American reprint already in the market, and at one-third of the price

of the imported book. In order to make this reproduction, the sheets of

the English volume are carefully photographed, and the glass negative

placed over a thick sheet of specially prepared gelatine and exposed

to the sun. Wherever the dark film upon the glass negative prevents

the light from reaching the surface of the gelatine, this substance

remains insoluble in water. Wherever the light penetrates, the gelatine

undergoes a chemical change which makes it soluble. After an exposure

to the sun or electric light for some minutes, the gelatine sheet is

washed with water and the result is a plate in relief, every black

line upon the glass negative being in high relief, and everything else

washing away under the sponge.

“Until the last few years, it had been very difficult to get this

relief sufficient to print from, but by improvements in the process

effected by a number of different inventors, this result has been

obtained. The gelatine sheet having been hardened, an electrotype is

made from it which is put into the printing press. Owing to chance, the

gelatine sheet itself was used one day for printing from directly, and

it was found that a larger number of good copies could be made from the

gelatine direct than from the hardest electrotype. The only drawback

to the use of the gelatine plate itself in the printing press is its

liability to crack, for no reason that has as yet been discovered. If

some way is found of making the gelatine plate durable, it would be

used entirely in place of an electrotype, as it costs almost nothing

and can be made quicker than an electrotype.”

The way has been “found” and zinc etching is doing the work.

Finally, the essays of John Burnet, “On the Education of the Eye,” “On

Composition,” and “On Light and Shade,” copies of which are hard to get

for $100, have recently been reproduced by one of the processes given

in this book, full size, and is sold at $4.00. There is a great future

ahead for all process work.

|181|

INDEX.

Acid, lateral action of the, 80

Acids, on the use of, 100

Actinometer, to make an, 107

Air brush, grain with the, 100

Albumen, coating the zinc plate with sensitive, 41

― etching in half tone, 69

― printing on the zinc in, 45

Albumenized zinc plate, inking the, 46

Albumenizing the glass plate, 21

Alcohol lamp, the, 98

All sources, hints from, 94

Apparatus etching, 97

― for printing upon zinc, 39

Appliances for making negatives, 9

As to the drawing, 94

Austrian method, etching on, 84

― middle etching, 87

Bath, the nitrate of silver, 12, 16, 27

Beer, preliminary coating of, 164, 170

Bitumen, printing on zinc in, 48

― etching in half tone, 70

― image on zinc, developing the, 50

― solution, to make the, 48

Black process, Colas’s, 109

Blackening in with a sponge, 78

Block, printing from the half tone, 72

Board, the developing, 141

Box, the best drying, 99

Bridge, the calibre, 93

Calibre-bridge, the, 93

Camera, the enlarging, 67

Carbon printing, 106

― tissue for reproductions, 32

Chiseling illustrated, 90

Clean etching, 91

Clearing solution, the, 18

― the glass, 21

Coating the zinc plate with sensitive albumen, 41

Colas’s black process, 109

Collodion process, the wet, 11

― film, protecting the, 20

― ― stripping, 34

Collotype process, the, 163

― ― sensitizing solution for, 164

― film, exposure at the back of the, 166

― ― exposure of the, 165

― operations, the, 167

― plate, printing from the, 171

― ― the finished, 67

― process, drying oven for the, 167, 174

Copper, mordants for, 112

― photo-engraving on, 119

― ― in line, 119

― relief, mordants for, 113

― solution, etching with sulphate of, 103

Damping fluids for collotype printing, 173

Dark-room, the, 25

Deep etching, 89

Developer for wet plates, 24

― for gelatine dry plates, 30

Developing the albumen image on the zinc plate, 42

― the bitumen image on the zinc plate, 50

― the paper transfer, 138

Developing-board, the, 141

Difference in processes, the, 117

Direct transfers to zinc, 51

Drawing, transfer of the, 83

― as to the, 94

― treatment of the, 73

Drawings, Colas’s process for reproducing, 109

― for photo-engraving, 51, 73

― the reversal of, 96

Dry plates in photo-engraving, 29

Drying-box, the best, 99

Drying oven for the collotype process, 167, 174

― the zinc plate, 42

Dusting-box, the, 124

Dusting sieve, 98

― the transfers, 54

Electrotype methods for half-tone intaglios, 127

Engraving, photo-, in half tone, 63

Enlarging camera, the, 68

Etching apparatus, 97

― clean, 91

― cleaning the, with a scraper, 88

― deep, 89

― ― illustrated, 90

― finishing and mounting the, 92

― fluids for collotype prints, 173

― galvanic process of, 101

― in half-tone (albumen), 69

― ― ― (bitumen), 70

― in relief, high, 104

― intermediate treatment, 79

― line transfers, 55

― manipulations of the process of, 93

― middle, Austrian method, 87

― ― and deep, illustrated, 88

― mordants for, 109

― ― for electric, 113

― ― for relief, 113

― ― for tint, 113

― ― for zinc, 115

― on copper, 121

― order of the manipulations, 86

― round, 88

― the Austrian method, 84

― ― illustrated, 88

― the first zinc, 57

― the French method of, 76, 80

― the second zinc, 58

― with sulphate of copper solution, 103

― zincographic, 115

Exposed zinc, inking the, 44

Exposure and timing, 43

― of the collotype film, 166

― ― ― ― ― at the back, 166

Fading out the photograph, 96

Faults in strengthening, 78

Finishing and mounting the etching, 92

Fixing, solution, the, 18

Fluids, damping, for collotype printing, 173

― etching, for collotype printing, 173

French method of etching, 76, 80

Further treatment of the transfers, 16

Galvanic process for etching, 102

Gelatine dry plates in photo-engraving, 29

Gillotage (Gillot’s process), 101

Glass, albumenizing the, 22

― plate, the, 21

― silvering the, for mirrors, 36

Grain on a negative, to produce, 100

Grained negatives, making, 65

― ― transparencies for, 66

Graining the zinc plate, 40

Half-tone photo-engraving, 63

― ― etching in (albumen), 69

― ― ― ― (bitumen), 70

― ― block, printing from the, 72

― ― intaglios, 122, 124

― photo-lithography in, 143

Heliotype process, the, 152

― skin, the, 160

― ― printing the, 158

― ― mounting on pewter, 159

High etching in relief, 104

― ― dusting-box for, 124

― ― electrotype method for, 127

Hints from all sources, 94

Husband’s papyrotint process, 147

Ink for transfers, hard, 55

Inking the exposed zinc, 44

― transfers, 54

Ink-photos, 144

Intaglios, half-tone, 122, 124

― dusting-box for, 124

― electrotype methods for, 127

Intensifier, the, 18

Lamp, the alcohol, 99

Lateral action of the acid, 80

Line, photo-engraving in, 9

― ― on copper in, 119

― photo-lithography in, 128

Line transfers, etching, 56

― ― ink for, 56

Making grained negatives, 65

Manipulations in etching, order of the, 86

Manipulations of the etching process, 93

Manipulations, photographic, 24

Mask, the, 156

Middle etching, Austrian method, 87

― ― French method, 80

Mirror, the reversing, 10, 35

Mordants for copper, 112

― for etching, 109

Mounting and finishing the etching, 92

― the cliché, before, 79

― the zinc etching, 61

Negative printing, 96

― ― to produce grain on a, 100

― transfer process, Toovey’s, 139

― washing, 19, 28

Negatives, appliances for making, 9

― making grained, 65

― screen for grained, 65

― the reproduction of, 31

― transparencies for grained, 66

Nitrate of silver bath, the, 12, 16

Oven for the collotype process, drying, 167, 174

― using the, 168

Paper transfers, 132, 136

― ― developing the, 138

― ― ― ― sensitizing solution for, 137

Papyrotint process, Husband’s, 147

Pewter plate, mounting on the, 159

― ― the, 156

Photo-engraving, half tone, 63

Photo-engraving in line, 9

Photograph, fading out the, 96

Photographic manipulations, 24

― negatives, appliances for making, 9

Photo-inks, 144

Photo-lithographic transfers, to develop, 140

Photo-lithography in half-tone, 143

― in line, 129

Plate, graining the zinc, 40

― the glass, 21

― the pewter, 156

Polishing the zinc, 39

Pomatum wax, how to make, 81

Positives for negative reproduction, 31

Preparation of the rollers, 154

Preparing the printing press, 176

Printing, carbon, 106

― collographic, 172

― ― damping fluids for, 173

― ― etching fluids for, 173

Printing frame, the, 43

Printing from the collotype plate, 171

― from the half-tone block, 72

― press, preparing etchings for, 102

― ― preparing the, 176

― process, the new home, 178

― the heliotype skin, 160

― upon zinc, apparatus for, 39

― ― ― in albumen, 45

― ― ― in bitumen, 48

Processes, the difference in, 117

Process, the collotype, 163

― the heliotype, 152

― the wet collodion, 11

Protecting the collodion film, 20

Relief, high etching in, 104

Reproduction of drawings, Colas’s process, 109

Reproduction of negatives, the, 31

― with carbon positive, 32

Retrospective, half-tone photo-engraving, 63

Reversal of the drawings, 96

Reversing mirror, the, 10, 35

Rollers, the, 153

― preparation of the, 154

Room, the dark-, 25

Round etching, 90

Running of a workshop, 104

Screen for grained negatives, the, 65

Sensitometer, to make a, 107

Sensitizing solution, a good, 105

Sensitizing solution for paper transfers, 132

― ― for the collotype process, 165

Sieve, dusting, 98

Silver bath, the nitrate of, 12, 16

Silvering the glass (for mirrors), 26

Skin, the heliotype, 156

― mounting on pewter, 159

― printing from the heliotype, 160

― printing the heliotype, 158

Solution, clearing the, 18

― developing the, 17

― fixing the, 18

― intensifying the, 18

Sources, hints from all, 94

Stereotyping, zinc etching by, 102

Strengthening, faults in, 78

― French process, 82

Stripping collodion films, 34

Sulphate of copper solution, etching with, 103

Table, the washing, 98

Timing and exposure, 43

Toovey’s negative transfer process, 139

Transfer process, Toovey’s negative, 139

― and treatment of the drawing, 73

― of the drawing, 73, 83

― paper, 132, 136

Transfers, developing the, 138

― dusting the, 54

― etching line, 55

― further treatment of the, 76

― ink for line, 56

― inking the, 54

― photo-litho, 140

― to develop, 140

Transfers to zinc, direct, 51

Transparencies for grained negatives, 66

Transparencies, how to make, 30

Transparent positive, making the, 120

― ― sensitizing the, 137

Treatment before mounting, 78

Washing, Austrian process for, 85

― French process for, 83

Washing table, the, 98

― the negative, 19

Wax pomatum, how to make, 81

Whirler, the, 42

Work-shop, running of the, 104

Wrinkles and dodges, 105

Zinc, apparatus for printing upon, 39

― ― direct transfers to, 51

― etching the first, 57

― ― by galvanic means, 102

― ― by stereotyping, 102

― ― mounting the, 61

― ― the second, 58

― ― the manipulations of, 93

― in albumen, printing on the, 45

― in bitumen, printing on the, 48

― inking the exposed, 44

― plate, developing the albumen image on the, 47

― ― ― the bitumen image on the, 50

― ― ― inking the, 54

― ― graining the, 40

― ― coating with sensitive albumen, 41

― ― drying the, 42

― ― whirling the, 42

― ― inking the albumenized, 46

― ― the, to coat with bitumen, 49

― polishing the, 39

― preparing on the press, 102

Zincographic etching, 115

― printing press, the, 62

Glue rollers should be hung up after use in a cold place, and before