(Read before the Photographic Society, Nov. 3, 1853.)
I feel that some few words are required to explain to the Society the
reasons which have induced me to call their attention to a branch of
photography, which of all others has been dwelt upon most fully, and
practised with such success by so many eminent photographers.
The flourishing state of this Society, which is constantly receiving an
accession of new Members, indicates the great number that have lately
commenced the practice of photography, and to those I hope my observations
will not prove unacceptable, because of all others the calotype process is
undoubtedly the simplest, and the most useful; not only from that
simplicity, but from its being available when other modes could not be
used.[2]
I am also induced to urge on the attention of the Society the advantages of
this, one of the earliest processes, because I think that there has been
lately such an eager desire for something new, that we all have more or
less run away from a steady wish to improve if possible the original
details of Mr. Fox Talbot; and have been tempted to practise new modes,
entailing much more care and trouble, without attaining a correspondingly
favourable result.
Amongst antiquaries I have long noticed, that many who have especially
studied one particular {597} branch of archaeology, think and speak
slightingly of those departments in which they are not much interested. One
fond of research in the early tumuli is esteemed to be a mere "pot and pan
antiquary" by one who, in his turn, is thought to waste his time on
"mediaeval trash;" and this feeling pervades its many sections.
I hope I shall not give offence in saying, that amongst photographers I
have noticed somewhat of a similar spirit, namely, an inclination to value
and praise a production, from the particular mode of operation adopted,
rather than from its intrinsic merits. The collodion, the waxed paper, or
the simple paper processes have merits pertaining to themselves alone; and
those who admire each of these several processes are too apt to be
prejudiced in favour of the works produced by them.
Before proceeding farther, permit me to observe, that if some of my remarks
appear _too_ elementary, and _too_ well known by many assembled here, my
reason for making them is, that I have myself experienced the want of
_plain simple rules_, notwithstanding the many able treatises upon the
subject which have already been written: I hope, therefore, I shall receive
their pardon for entering fully into detail, because a want of success may
depend upon what may appear most trivial.
I think the greatest number of failures result from not having good iodized
paper; which may be caused by
1. The quality of the paper;
2. The mode of preparing it;
3. The want of proper _definite_ proportions for a particular make of
paper;
because I find very different results ensue unless these things are
relatively considered.
I have not met with satisfactory results in iodizing the French and German
papers, and the thick papers of some of our English makers are quite
useless.
Turner's paper, of the "Chafford Mills" make, is greatly to be preferred,
and therefore I will presume that to be used, and of a medium thickness.
The great fault of Turner's paper consists in the frequent occurrence of
spots, depending upon minute portions of brass coming from the machinery,
or from the rims of buttons left in the rags when being reduced to pulp,
and thus a single button chopped up will contaminate a large portion of
paper; occasionally these particles are so large that they reduce the
silver solutions to the metallic state, which is formed on the paper; at
other times they are so minute as to simply decompose the solution, and
white spots are left, much injuring the effect of the picture.
Whatman's paper is much more free from blemishes, but it is not so fine and
compact in its texture; the skies in particular exhibiting a minutely
speckled appearance, and the whole picture admitting of much less
definition.[3]
All papers are much improved by age; probably in consequence of a change
which the size undergoes by time. It is therefore advisable that the
photographer, when he meets with a desirable paper, should lay in a store
for use beyond his immediate wants.
It may not be inappropriate to mention here, in reference to the minuteness
attainable by paper negatives, that a railway notice of six lines is
perfectly legible, and even the erasure for a new secretary's name is
discernible in the accompanying specimen, which was obtained with one of
Ross's landscape lenses, without any stop whatever being used, and after an
exposure of five minutes _during a heavy rain_. The sky is scarcely so
dense as could be desired, which will be fully accounted for by the dull
state of the atmosphere during the exposure in the camera.
Having selected your paper as free from blemishes as possible, which is
most readily ascertained by holding it up to the light (as the rejected
sheets do perfectly well for positives, it is well to reject _all_ those
upon which _any_ doubt exists), mark the smoothest surface;--the touch will
always indicate this, but it is well at all times not to handle the
surfaces of papers more than can be avoided. There is much difference in
various individuals in this respect; some will leave a mark upon the
slightest touch, whereas others may rub the paper about with perfect
impunity.
I prefer paper iodized by the single process; because, independently of the
case and economy of time, I think more rapidity of action is attained by
paper so treated, as well as that greater intensity of the blacks, so
requisite for producing a clear picture in after printing.
To do this, take sixty grains of nitrate of silver and sixty grains of
iodide of potassium, dissolve each separately in an ounce of distilled
water, mix and stir briskly with a glass rod so as to ensure their
_perfect_ mixture; the precipitated iodide of silver will fall to the
bottom of the vessel; pour off the fluid, wash once with a little distilled
water, then pour upon it four ounces of distilled water, and add 650 grains
of iodide of potassium, which _should_ perfectly redissolve the silver and
form a clear fluid. Should it not (for chemicals differ occasionally in
their purity), then a little more should be very cautiously added until the
fluid is perfectly clear.
The marked side of the paper should then be carefully laid upon the surface
of this fluid in a proper porcelain or glass dish. Then immediately {598}
remove it, lay it upon its dry side upon a piece of blotting-paper, and
stroke it over once or twice with a glass rod; this as effectually expels
all the particles of air as complete immersion; it is also more economical,
and has the advantage of requiring much less time in the after-immersion in
the hypo. when it is required to remove the iodide. Either pin the paper
up, or lay it down upon its dry side, and when it becomes tolerably dry
(perfect dryness is not requisite), immerse it in common cold water for the
space of four hours, changing the water during that time three or four
times, so that all the soluble salts may be removed; often move the papers,
so that when several sheets are together, one does not press so much upon
another that the water does not equally arrive at all the surface.
If this paper is well made, it is of a pale straw colour, or rather
primrose, and perfectly free from unevenness of tint. It will keep good for
several years; if, however, the soluble salts have not been _entirely_
removed, it attracts damp, and becomes brown and useless or uncertain in
its application.
Some of our oldest and most successful operators still adhere to and prefer
the iodized paper prepared by the double process, which certainly effects a
saving in the use of the iodide of potassium. The following is the easiest
way of so preparing it:--Having floated your marked surface of the paper on
a 30-grain solution of nitrate of silver, and dried it[4], immerse it for
20 minutes in a solution of iodide of potassium of 20 grains to the ounce,
when it immediately assumes the desired colour. It is then requisite,
however, that it should undergo the same washing in pure water as the paper
prepared by the single process.
Upon the goodness of your iodized paper of course depends your future
success. Although it is not requisite to prepare it by candle-light (which
in fact is objectionable from your inability to see if the yellow tint is
equally produced), I think it should not be exposed to too strong a light;
and as the fly-fisher in the dull winter months prepares his flies ready
for the approaching spring, so may the photographer in the dull weather
which now prevails, with much advantage prepare his stock of iodized paper
ready for the approach of fine weather.[5]
Many other ways of iodizing paper have been recommended which have proved
successful in different hands. Dr. Mansell, of Guernsey, pours the iodide
solution upon his paper, which previously has had all its edges turned up
so as to resemble a dish; he rapidly pours it off again after it has
completely covered the paper, and then washes it in three waters for only
ten minutes in all: he considers that thereby none of the size of the paper
is removed, and a more favourable action is obtained. In the experiments I
have tried with the use of the air-pump, as recommended by Mr. Stewart, I
have met with much trouble and little success; and I am inclined to
attribute the very beautiful specimens which he has produced to his own
good manipulation under a favourable climate.[6]
To excite the paper take 10 drops (minims) of solution of aceto-nitrate of
silver, and 10 drops of saturated solution of gallic acid, mixed with 3
drachms of distilled water.