Jack Fulton said he has a good black cyanotype toner & suggests posting
(or in some cases re-posting) these formulas. So here's our favorite,
most successful 2-bath toner to get the ball rolling. Hope others will
add their secrets. (Then maybe someone whose screen editor is less
hostile and primitive, not to mention punitive, than mine, will put them
together?!)
And I apologize for the delay -- I had to check my notes now at school.
*Two-Tray Brown-Black Toner for Cyanotype*
Solution A. 1 teaspoon tannic acid in l litre of water.(Note: 1 tsp = 2
grams. This is a VERY flexible measurement. Many formulas say stronger.)
Solution B. 2 teaspoons sodium carbonate in 1000 cc water. (Note: I have
this as 15 grams in my notes, a measurement made by an assistant flake
some years ago. A student this year tells me 2 tsps is NOT 15 grams.
Whatever, as noted above, timing & strength very flexible. We generally
use the dry measure.)
Got all that?
OK. Start by immersing the print (pre-soaked or dry, but not right out of
wash water from being made -- has to dry/harden first) in solution A,
tannic acid. Take two minutes as your base time if you want to be
quantitatively authoritative; but this is one of the ones we do by feel.
Now rinse in clear water for maybe a minute. I think this is to preserve
your solution B......
Bathe print briefly (less than minute) in B and rinse again. Now BACK
into A, which is where the color happens. Watch carefully and if you want
a split tone, snatch the print out BEFORE it gets to the color you want
because, just as in ferricyanide bleaching, chemical remains in the paper
and action continues after it's in the rinse bath.
Strictly speaking, to save lots of changing of water, you need 3 rinse
trays -- one for after the first tannic bath; one for after the first
carbonate bath, and one for the finished print. But this is honored in
the breach, so to speak (in the bleach?).
If, BTW, you're not happy with the tone, you can continue back and forth.
You may ruin it, you may contaminate the baths, you may turn any of them
or the rinse bath into a toner itself by carry-over. But the idea is
to spoil prints -- and come up with just a few wonderful, special,
precious ones. Cyanotype is too easy anyway.
I give students more or less the advice above & they go their own way.
Some like to use very small amounts as a one-shot toner. Others seem able
to use and use and use one set of baths without getting strong paper base
stain (which is the pitfall to look out for). And one student today
brought in toned cyanotype where the paperbase was fairly stained,
"harmonizing" a too-contrasty print.
A similar formula, by the way, uses about 15 drops of household ammonia
per ounce (30cc) of water for the B solution and a much stronger tannic
acid for the B solution (10 grams per litre). My notes on this say
bleach first in the ammonia and tone on the tannic until the desired
color. I found this worked years ago, and students have used it with
good results. But the one we generally do in class is the sodium
carbonate & that's the one I'm most comfortable & familiar with.
Remember, the toning does cost density, so you want to start with a print
that borders on (or is well into) too dark. I suggest also starting with
at least two identical 21-step prints, tone one and keep other for
comparison -- see where split happens, how much density is lost, if
midtones flatten out, etc. And of course no law says you have to do split
tone -- you can go all the way to chocolate, also nice.
Feedback, please.
Judy