From: Christina Z. Anderson (zphoto@montana.net)
Date: 03/31/03-09:41:40 AM Z
> You may run into trouble using such a freshly mixed emulsion -- I found it
> tends to wash off, or require much more exposure, unless it has "ripened"
> for a day. My exposures average 8 minutes -- the same as VDB & platinum.
> Tho that's affected by the density of the negative, and the light source,
> also the paper.
> Judy
This is interesting, Judy, (you must be using Ware's formula?) because
traditional cyano, even mixed 2A:1B, was about 2 stops slower for me than
Ware's cyanotype formula, and way slower than anything else I've been
experimenting with. I have notes from Sandy King, too, that says in tests
VDB was 2 stops faster than cyanotype--don't know if he mixed cyano 2:1 or
1:1 (Sandy?) but I assume 1A:1B. He has carbon, gum, and VDB as 2 stops
faster than cyano, and kallitype as 1 stop faster than cyano. His tests
corroborate with my experience.
The slow time of cyano is wonderful in that you are not rushing around,
watching your watch...so what if you are off a minute. It is a thoughtful,
sit and have a cup of coffee kind of process.
My testing times, even with thin imagesetter negs, start at 20 minutes.
Now, Ware's cyanotype is a different story, being much faster.
Argyrotype, which I have been printing side by side with cyano
traditional and Ware's, is quite fast. I do my testing at 8 min (all these
in a BL UV box), and found between 6 and 12 was fine for most of my negs.
The color of argyros is so delectable, like bittersweet chocolate. And
so easy. And furthermore, I've found that heck, if it is too dark, which
some were at 8 minutes even with a 2.0 DR neg, you can bleach back in a mere
*tsp* of potassium ferricyanide to *2* liters of water and get a perfect
print. Watch it, tho--it goes extremely fast, and continues in the wash
water a bit, so you can lose a print if you are not careful. But that way,
with argyrotype, you can always err on the side of overexposure and correct
(with a fix afterwards, of course). Argyrotype on Buxton paper looks like
brown velvet.
I'm not surprised Shelley's exposure was almost 2 hr in rainy weather.
Another one of these tidbits I've picked up from research--from Ware's
book--is that the sun is about several times faster than artificial sources,
and the north sky is 1/10 the speed of direct sun. North sky would even be
more sunlight, I would think, than cloudy/rainy. So a 20 minute exposure
under UV would equate to 7 minutes in the sun and 70 minutes under north sky
(and who knows what under rain). Does anyone's research agree with Ware's?
Chris
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