[Alt-photo] Re: casein on glass

[Matti Koskinen]

On 7.6.2013 4:56, Jorj Bauer wrote:
>> I've been long enough a consumer and not a producer, so I wrote a page of my casein method. It's on http://www.mattikoskinenphoto.com/casein
> Looks like you're off to a great start! I'm glad to see someone else performing this process. My prints are really striking when backlit, and I bet yours are too.
Yep, in summer of 2011 I started to experiment, tempera and casein, when 
I got dichromate. Long before that, 2002 probably a big pharmacy could 
order dichromate, but when I asked them, they said it's not available 
any longer. But my cyano-chemical supplier hopeavedos.fi had dichromate 
luckily, so I ordered a small amount. And making a small bottle of 
saturated solution, doesn't need much of dichromate.
>
> I might recommend that you register your negatives to the edges of the glass, since you noticed problems with the registration. And I'd also recommend that you try printing on both the front and back of the pane of glass, rather than double-printing on one side. If you double-print, you wind up washing away some of the detail of the first print when you brush on the second coat of casein (creating a higher-contrast layer in the process). If you print on the backside of an already-printed pane of glass, you can carefully wash it (I rest mine on top of two sponges supporting the pane of glass in the tray) and not affect the quality of the first printing.
I tried registration using edges of the negative and the glass, but 
still there were small errors. So this made me experiment doing double 
coating and one exposure. The dmax is quite acceptable.
>> And a question: What are the names for CMY-colours, I think C is Prussian Blue, but M and Y? I'm using acrylic paints.
> I use Schmincke pigments:
>
>    C: helio cerulean
>    M: permanent carmine
>    Y: translucent yellow
>
> I've also used cadmium yellow (when I want the day-glow look), or pthalo blue (for a more glow-y cyan).
>
> And occasionally I use W&N's permanent carmine (when it's cheaper than Schmincke's at the local art store).
>
> -- Jorj
>
thanks, the world of colour is the next thing to try.

-matti