Re: report on cynotype and acid and a chemistry question.

Hi Chris,

The 2:1 ratio came from a handout by John P. Shaefer (past president of
U of Arizona who started the Center for Creative Photography and author
of the Ansel Adam's Guides, and a chemist) which suggested that the B
solution was not necessary for light sensitivity and when it's cut in
half the emulsion would be faster with no adverse effect. My experience
concurs. "Less is more" and I've been using this ratio since.

This ratio does not increase DMax nor the color though. That's a whole
mountain of wax altogether.

By the way, it was Keith Schreiber who gave me Shaefer's handout. And I
did try using no B in coating and using B just to develop. Worked, but
there didn't seem to be any reason to do it that way.

Thanks for dragging me into this Chris!
Sam

On Oct 27, 2005, at 10:12 PM, Christina Z. Anderson wrote:

> Carmen and Tom
>
> I do not take credit for the 2A:1B; this is a formula from Sam Wang,
> who prints incredible cyanotypes. Sam, in turn, learned it from
> another bigwig whose name I cannot remember. Both Sam and this guy did
> extensive testing of the different formulae and this was their
> finding. Maybe Sam will chime in here with who the guy was. My
> exposures under UVBL are about 6 minutes.
>
> I have not experienced any bleeding at all in the darks so I'm not
> sure why James suggests this. However, I no longer use, nor need, any
> citric acid or vinegar or those kinds of things. Vinegar just ended
> up mordanting the cyanotype to my bathtub, my trays, my everything (I
> was going to say "nuts" but I held myself back).
> Chris
> PS Carmen, I understand the 10 hour teaching day thing. I have been
> pushing that for 9 weeks now...luckily my fridays are free to play
> catchup and also print!
Received on Fri Oct 28 08:07:50 2005