Loris - I wonder if soaking/washing the paper prior to coating would
change the way it works with cyanotype.
If the paper has some sort of sizing or finish of some kind soaking it may
remove or alter something the manufacturer put in the paper. I don't
remeber if you said what kind of paper you are using.
A soak/wash prior to coating may raise the knap of the paper and make it
more absorbant. You will have to let the paper dry before coating.
Have no idea whether this would change anything - but its an easy thing to
try.
I've always suspected thay cyanotype is very sensitive to the pH of paper.
Is there a standard way of checing the pH of paper. I don't have a pH
meter, but I have plenty of litmus paper.
Oh - by the way - Rick's cyanotypes or gorgeous :)
Gord
On Wed, 19 May 2004, Loris Medici wrote:
> Judy, happy for you but ... blue water is a standard issue for me (I double
> coat). That's why I'm overexposing my cyanotypes incredibly - I never
> understood the "expose for highlights becoming one - one and a half stop
> darker than what you want in the final print" suggestion... If I do it that
> way, I get empty highlights, highlight-like midtones and weak shadows. But
> if I expose the print until the shadows are completely reversed, midtones
> reversed but less than shadows and highlights blue (zone IV I'd say) then I
> get the print I want (after the print turning the first development tray
> dark green/prussian blue - 2 mins - and the second one very weak cyan/aqua -
> 2 mins - and clear in the third one - again 2 mins). The only case I hadn't
> blue water was when I was adding gum arabic (4 drops to 20ml sensitizer) and
> 10% potassium dichromate (2 - 3 drops to 20ml sensitizer) to the emulsion.
> In that case the shadows would look almost whitish in development and won't
> dissolve in the development water (in my case, it's mainly the dissolving of
> shadows that makes the water prussian blue) and sometimes it would convert
> to deep blue in peroxide bath only, not before. And yes, my paper's not very
> absorbent - I had best results adding 2 - 3 drops of ILFOTOL to 20ml
> sensitizer (that's a wetting agent similar to Photo-Flo) - but I don't see
> any puddling when I coat; the paper gets matte in one to two mins. BTW, I
> use 0.1% citric acid as developer (1gr to 1lt) in order to compensate -
> maybe - alkaline wash water (not scientific, I didn't even try to measure
> the PH of our tap water - what I know is it stinks chlorine!).
>
> Regards,
> Loris.
>
>
---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@duke.usask.ca 112 Science Place
http://duke.usask.ca/~holtsg University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
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Received on Wed May 19 23:15:22 2004
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