Great information guys, thanks! I went down a made a few more tissues. I've got that part of it down now. I used my glass coating rod after I soaked it in hot water, to spread the glop inside the magnetic frame. Got a really nice, bubble free coating. The next time I mix up the glop, I'll reduce the amount of sugar, and then perhaps at another stage, reduce the amount of Isopropyl...Just waiting now for the formalin to arrive, then I can coat some paper.
Sandy, sometimes my darkroom can hit 70%RH or higher, but I can get it down to 50% with my trusty little dehumidifier. The last few sheets I coated worked well at 50%, so that'll be my target RH.
Dave, thanks for the tip on where to source Acetone...I'll try Rona across from Coquitlam Centre first to see if they have any.
Have fun, Andrew! (And I'll assume you meant Ammonium dichromate -- not formalin...unless I missed something)
PS...I had to google "Rona"...too curious and had to find out. Sort of disappointed it is just Canada's equivilent to Home Depot.
yup, formalin AND ammonium dichromate...I was getting too excited about sourcing acetone I guess.
Rona used to be Revy and before that I believe it was called Beaver Lumber.
Can't wait to sensitize my tissues and get printing!
Well, I checked the first tissue that I made and I can see that it is starting to dry out. AND I picked up some acetone at Rona.
If fixed out photographic film works as a tissue base, cheap inkjet transparency film (used to make overhead projector slides) probably would too. One side of that material has a thin gelatin coat to accept the ink. A possible problem is thickness. Inkjet film is thinner that sheet film, and it will probably curl more. I've heard that ordinary artist's mylar (available in rolls quite cheaply) also works. I haven't tried any of these.
Andrew, where are you getting your chromium salts? B&S in the states has really good prices for most chemicals but they can't ship the dichromates across the border so I'm very interested in more local sources!
I get my chemicals from jdphotochem in Quebec. Ammomium dichromat 100g $12 as listed on their website, but it actually costs $21. Their web site hasn't been updated for years.
Sheet film is thicker than one needs. The litho film I use is about half the thickness of sheet film (.004" vs .007"). The test is to put the support material in hot water to see if it deforms or falls apart (it should do neither).
Originally Posted by nworth
If one brush sensitizes, 100 grams of Ammonium dichromate will last a while. For tissues to print 8x10 negatives, one might be using only 0.1 to 0.6 grams per tissue...depending on the concentration used (lower concentrations will yield prints with more contrast).
Have you ever did multiple hits in register with your process?
I would like to make separation negatives to isolate specific areas in the image and am sourcing ways of preventing the paper from shrinking with multiple coatings.
I have decided mounting thick thick paper to lexan and then punching the whole print and then stripping the additional films in register to print multiple hits.
Then I would peel the paper from the support lexan and thus removing the mounting tissue which may be suspect for archival properties.
Any thoughts on multiple registration when working with Carbon.
Bob, this is one area of carbon printing I have no personal experience with. The late Gordon Chappel showed me his set-up...he used anywhere from a single layer to 4 or 5 layers, and I am trying to remember what he used as a final support material (non-shrinking). But I am not being successful. I wonder is just pre-shrinking the paper (soaking and drying a couple times) and then taping it down on all sides to the registration board might be enough...but this is just me thinking aloud. The synthetic watercolor paper, Yupo, may not shrink.
This would be a good question for the folks over on the carbon printing forum I linked to earlier. Sandy King started off do 3 color carbons, so he would be able to give some solid advise over there.