Re: Casein -> it's the paint

[Guido Ceuppens <altguido@gmail.com>]

Hi Loris,
Been away from computers for a few weeks so I can only chime in a bit late:
I have been using casein/acryl mixtures for quit a long time now and
find it a favourite as it can produce very colourful  images and seems
to be more sensitive and easier to use than gum/waterpaint but
requires a more vigorous manual "development" . I have used it on
paper sized with gelatine, gesso or white latex paint, and even on
gesso-ed artists canvas.
There seems to be two types of powdered casein on the market: my
favourite is the white fine powder, but it also comes as a coarser
yellowish sand-like powder. The fine white stuff dissolves quite
easily but the coarse casein takes more time and a different
technique.

My recipe for dissolving the fine white stuff:
15 gr casein in 100 ml water, stir : the casein does not dissolve but
is more or less evenly dispersed in the water. Dissolve 2.5 gr borax
in 25 ml boiling water. Immediately add the hot borax solution to the
casein and stir vigorously for a minute, let stand until cooled off,
ready.
The solution does not smell badly and when de-ionised water is used,
this solution can last a few days, until it stinks and gets watery.

When only the coarser, yellow casein is available I prepare it as follows:
15 gr casein in 75 ml water, stir and heat to very hot, but do not boil.
Dissolve 4.5 gr ammonium carbonate in 25 ml warm water, add to the
casein while stirring and keep warm for approx. 15 min whilst stirring
occasionally. Again let cool down.
This version smells strongly af ammonia.

I add acrylic paint usually 1 part of paint to 4 to 12 parts (in
weight) of casein.

 As an example, the following image was made in 4 printings (using 4
oiled paper CMYK negatives):
Paper: Schut acryl board, a thick but cheap paper, sized with two
coats of (undiluted)  latex white paint.
1.	Yellow : (Y negative) 1 part Reeves Medium Yellow + 6 parts casein
+ 3 parts Pot dichromate.
Dried with a hairdryer on high heat. Exposed for 30 sec. Stand
developed for 10 minutes then "cleared" with a soft brush (hake) to my
taste.
2.	Red : (M negative) 1 part Reeves Brilliant Red + 8 parts casein + 4
parts Pot dichromate. Dried with a hairdryer on high heat. Exposed for
30 sec. Stand developed for 10 minutes then again "cleared" with a
soft brush (hake).
3.	Blue :(C negative) 1 part Daler Rowney Process Cyan + 12 parts
casein + 6 parts Pot dichromate. Exposure 20 sec. Stand developed for
20 minutes, no brushing.
4.	Black :(K negative) 1 part Reeves Mars Black + 10 parts casein + 5
parts Pot dichromate. Exposed for 45 sec. Stand developed for 10
minutes then "cleared" with a soft brush (hake).

http://home.versateladsl.be/vt6100419/AltPhot/Landschap/loveisall.html

Best,
Guido


2009/5/24 Loris Medici <mail@loris.medici.name>:
> Hi all,
>
> I tried with powdered pigment and this time (3rd trial) got an image. So,
>