[alt-photo] casein on metals

[Peter Friedrichsen]

I heard mention of casein as being a candidate for coating on 
metal...I think it was Marek, so I thought I would pass on my experience.

I have successfully coated, exposed and developed casein+dichromate 
on copper, aluminum, and even glass but there are challenges:

First, the metal must be very clean. I clean the surface with steel 
wool and a dusting of laundry detergent and scrub for several 
minutes. Some other cleaners such as dish soap don't seem to work so 
well. You will know the metal is clean when the water sheets off of 
the metal after a few minutes of rinsing. It is important that it 
sheets off, as any beading up will mean that the casein will not 
adhere sufficiently during development. Coating an even film on metal 
is a bit trickier than paper and I find that of all things, a 
silicone basting brush works well. Watch our for any bit of dust as 
it really shows itself on metal. Cleaning foils may need some other 
type of approach because they are so thin.

Even once you get the coating method perfected, you have a problem if 
you are hoping for tonality and that is that there won't be any. 
Lightly hardened casein (grey tones) prefers to stick to itself 
rather than the metal so it sloughs off and the result is a two tone 
image with no tones in between. I have heard that tonality can be 
accomplished with a carbon tissue transfer onto metal using the 
traditional carbon tissue but that does not involve casein of course. 
I won't say it isn't possible with casein but that I have not had any 
luck with it. There may be some type of undercoat that you could 
apply to help anchor the less exposed casein but I have not attempted 
it. An undercoat of  powdered silica+hardened casein may do the trick.

If anyone has anything to add re metals/glass whether it is casein or 
even gum, I am all ears.

Peter Friedrichsen