Re: papers for alt processes

Keith Schreiber (KEITH@ccp.arizona.edu)
Fri, 20 Oct 1995 15:00:46 -0700 (MST)

Bruce McCaughey wrote:

> While I'm asking for help I have another request. Does any one have
> hands on experience toning cyanotypes. Most books talk about toning and
> supply formulas but they are vague about the results. I've tried two
> methods and one had no effect and the other produced a lifeless brown. Does
> any one have a formula that they like to use to get away from Prussian
> blue.

I have tried several methods for toning cyanotypes with mostly less
than satisfactory results.

1. Deep Purple: Bleach in 5% ammonia, wash, then tone in saturated
sollution of tannic or gallic acid, wash. (I have tried this one
using tannic acid and would not call the results deep purple - more
like a vaguely purplish blue :-\)

2. Green: Tone in weak solution (1%) of sulfuric acid. Wash. (Again,
not really green - only greenish-blue :-/)

3. Red-brown: Treat for 5 minutes in tannic acid (6gm to 180ml
water), then sodium carbonate (6gm to 180ml water). Wash.
This one actually works :-)

If this last method is the one you have tried that produced a
"lifeless brown", perhaps a different paper would yield better
results. I think I used Strathmore drawing paper.

Hope this is of some help,
Keith
Keith Schreiber
Center for Creative Photography
University of Arizona
Tucson, Arizona 85721
520-621-7968
520-621-9444 FAX
keith@ccp.arizona.edu