Take powdered gall nuts and vitriol, powder them and spread them on
paper like a varnish, then write on it with a pen wetted with
spittle and it will turn as black as ink.
615.
If you want to make foreshortened letters stretch the paper in a
drawing frame and then draw your letters and cut them out, and make
the sunbeams pass through the holes on to another stretched paper,
and then fill up the angles that are wanting.
616.
This paper should be painted over with candle soot tempered with
thin glue, then smear the leaf thinly with white lead in oil as is
done to the letters in printing, and then print in the ordinary way.
Thus the leaf will appear shaded in the hollows and lighted on the
parts in relief; which however comes out here just the contrary.
[Footnote: This text, which accompanies a facsimile impression of a
leaf of sage, has already been published in the _Saggio delle Opere
di L. da Vinci_, Milano 1872, p. 11. G. GOVI observes on this
passage: "_Forse aveva egli pensato ancora a farsi un erbario, od
almeno a riprodurre facilmente su carta le forme e i particolari
delle foglie di diverse piante; poiche (modificando un metodo che
probabilmente gli eia stato insegnato da altri, e che piu tardi si
legge ripetuto in molti ricettarii e libri di segreti), accanto a
una foglia di Salvia impressa in nero su carta bianca, lascio
scritto: Questa carta ...
Erano i primi tentativi di quella riproduzione immediata delle parti
vegetali, che poi sotto il nome d'Impressione Naturale, fu condotta
a tanta perfezione in questi ultimi tempi dal signor de Hauer e da
altri_."]
617.
Very excellent will be a stiff white paper, made of the usual
mixture and filtered milk of an herb called calves foot; and when
this paper is prepared and damped and folded and wrapped up it may
be mixed with the mixture and thus left to dry; but if you break it
before it is moistened it becomes somewhat like the thin paste
called _lasagne_ and you may then damp it and wrap it up and put it
in the mixture and leave it to dry; or again this paper may be
covered with stiff transparent white and _sardonio_ and then damped
so that it may not form angles and then covered up with strong
transparent size and as soon as it is firm cut it two fingers, and
leave it to dry; again you may make stiff cardboard of _sardonio_
and dry it and then place it between two sheets of papyrus and break
it inside with a wooden mallet with a handle and then open it with
care holding the lower sheet of paper flat and firm so that the
broken pieces be not separated; then have a sheet of paper covered
with hot glue and apply it on the top of all these pieces and let
them stick fast; then turn it upside down and apply transparent size
several times in the spaces between the pieces, each time pouring in
first some black and then some stiff white and each time leaving it
to dry; then smooth it and polish it.
On the preparation and use of colours (618-627).
618.
To make a fine green take green and mix it with bitumen and you will
make the shadows darker. Then, for lighter [shades] green with
yellow ochre, and for still lighter green with yellow, and for the
high lights pure yellow; then mix green and turmeric together and
glaze every thing with it. To make a fine red take cinnabar or red
chalk or burnt ochre for the dark shadows and for the lighter ones
red chalk and vermilion and for the lights pure vermilion and then
glaze with fine lake. To make good oil for painting. One part of
oil, one of the first refining and one of the second.
619.
Use black in the shadow, and in the lights white, yellow, green,
vermilion and lake. Medium shadows; take the shadow as above and mix
it with the flesh tints just alluded to, adding to it a little
yellow and a little green and occasionally some lake; for the
shadows take green and lake for the middle shades.
[Footnote 618 and 619: If we may judge from the flourishes with
which the writing is ornamented these passages must have been
written in Leonardo's youth.]
620.
You can make a fine ochre by the same method as you use to make
white.
621.