From: Judy Seigel (jseigel@panix.com)
Date: 04/01/03-02:07:42 PM Z
On Mon, 31 Mar 2003, Christina Z. Anderson wrote:
> > 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.
Chris, all those numbers make my head spin... I can only say that the
exposures were not that different, but that I worked from a 21-step and
then measured the negative by densitometer -- that is, usually got the
exposure right first try without test strips, without formulas, without
math.
I generally made three 21-steps from the STANDARD cyanotype formula -- 1
part A, 1 part B, on whatever paper I was using. One was exposed 4
minutes, one 6 minutes, and one 8 minutes -- I wrote the step readings in
the margins, then compared with the readings of the negative I was
printing.
Then picked an exposure, which could of course be 5 minutes or 7 minutes
either, depending on the densities I was gearing to.
If your exposures are that different from mine -- who knows? Could be the
filtering effect of sunlight in the rocky mountains -- or your negatives,
different chemicals, different formulas, etc.... BUT...
....nobody has mentioned the different speeds of paper in cyano. Yesterday
filing something (still cleaning up) I opened an old folder of student
variables (and that's about the only way to find something around here --
by accident !).
Ali Manzo (no date) had done cyanotype, "Different Paper, all at 12
minutes." The first, on a "Carolina Drawing pad of 80 lb paper) was nicely
exposed with twelve (12 !) countable steps on the 21 step.
The second on Stonehenge (which is different today, tho not necessarily in
speed) showed almost no image and only 5 steps, tho almost same d-max.
The third on something called "Mohawk superfine 80 lb cover hi-finish
white" showed 5 EXTREMELY faint steps, the darkest of which was about like
step 12 on the Carolina, with only the faintest traces of image.
Hope I gave her an A.
Judy
> 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
>
>
>
This archive was generated by hypermail 2.1.5 : 05/01/03-11:59:53 AM Z CST