Re: Clearing cyanotypes, minimizing bleeding into highlights
I'll try to answer some of your questions.
Cyanotype is very paper sensitive. Is the Crane's Diploma Parchment the same as Cranes Weston? If so, it's one of the more fool proof papers to use.
With Cyanotype Classic formula, I use 2 parts A to 1 part B, with no Tween 20. In 50% humidity, I usually air dry for from 20 minutes to a couple of hours - the only problem with too short drying time is that the damp emulsion might stick to the negative or to the glass.
For exposure, I would cover a part of the coating with a piece of opaque paper, to insure it receives no exposure. That part would should be perfectly clear of blue after 'development'.
Adding a little acid to the water is a good idea. However, in your case I would try skipping the acid and see if your water needed it, and to see if that's the cause for your staining.
Yes, Mark was correct. I leave the print float up-side-down for 5 to 10 minutes. Then I would give it a gently rinse and hang up to dry. But running water over the print the whole time wouldn't be a problem, except in some cases it could get rid of some highlight densities.
With the right paper, the whole process is very simple and quick. You definitely don't need to watch movies in order to wait for it to dry!
On Jan 4, 2008, at 9:14 PM, Brian Pawlowski wrote:
Hi. My first post - and its a basic one. I've been wading through the archives and searching and reading all my references and I'm somewhat frustrated. The only thing holding me back from doing cyanotypes is the difficulties in clearing the print without blue bleeding into the highlights. I cannot maintain paper white. I've been using the PDN system to calibrate my exposures (been playing with Pd, POP, Silver - cyanotypes keep driving me back to Pd printing). Mark Nelson made some suggestions and I combined with some reading and interpolation and am doing: - Traditional Cyanotype (Bostick and Sullivan kit). 3:2 mix (A:B) - to increase speed. Two drops Tween 20 per 10ml emulsion. - Humidity is 50-60% in room - paper left out for at least 1/2 hour to stabilize. - Brush coat (hake brush), work emulsion to paper to get a consistent layer with fairly gentle strokes - Air dry about 2 hours (I know, I know - Mark keeps telling me to be consistent - I watch a movie during drying). - Been focusing on Crane's Diploma Parchment from B&S - calibrate to a 2m 56s exposure using 31 step tablet and X-rite 810 (I think) densitometer. (Diploma Parchment has much better wet strength than Crane's Platinotype had it seems to me) - Dmax 1.29+ (partly because I am not using hydrogen peroxide any more as I think it aggravated the bleeding into the highlight areas). And 21 steps of scale. - Mark passed on Sam Wang's (?) suggestion to clear the exposed paper inverted in a water bath. I add about 5 ml of a 1:100 dilution of Hydrochloric Acid to about 2 liters of clearing bath to start. - I run water into the bath slowly to allow the water to change out the blue and keep it up until it remains clear (about 1/2 hour). No hot water - so tap water circulating is about 50 deg F at this point? (don't have the Ph of my water - sorry). - Remove print, lay on paper towel - lay another sheet of paper towel on top - remove excess water, dry flat face up. I'm wondering if I am asking too much from the process? Any words of advice? Mark suggested someone had success with Arches Platine - which I had some of and I gave it a whirl - the paper is slower with the same steps above - by 1 stop or more? HELP! Thanks:-) And Happy New Year! Brian