The Keeping Pace newsletters can be found by googling "Making Enlarged Separation Negatives for the Ultra Stable Process" the first 2 links.
google "http://www.daviddoubley.com/Documents/KeepingPaceNewsletters/" for lots of them. They dont seem to be accesable directly from his site.
Seems most all Kiwo sensitisers contain formaldhyde but the % varies. http://www.snugz.com/Compliance/Ink/...itizerMSDS.pdf
Seems Ulano 925WR sensitiser contains formaldehyde. Unshure about Ulano RLX emulsion sensitiser but it costs $200 for a gallon of the stuff and I am not going to risk $200.
After reading the post on dye transfer group I have decided to try the sensitiser that comes with Kiwo 225WR as it is available in small quantities locally.
Printing without Dichromate would be good for my health and the environment. Diazo is much easier to get than Dichromate. Also presensitised tissue would speed up printing dramatically, the disadvantage being in controlling contrast but with digital negatives that is not a problem.
I still don't have anything definitive as to whether these formaldehyde condensate sensitizers are appropriate or not, but I think you are misreading that MSDS that you linked to. The composition is 89-99% of CAS #41432-19-3, and 1-11% of "Sodium salts", there's no suggestion of any free formaldehyde in this sensitzer, as I'm reading it.
I really hope to find sources for these sensitizer compounds separate from the emulsions. It seems both cost- and resource-inefficient to have to purchase and then discard the emulsion.
2 more questions for mdm:
-- Can you buy just the sensitizer for Kiwo 225WR, or do you plan on discarding the emulsion?
-- Do you have a link to the MSDS for the sensitizer (Kiwo Sensitizer #14)? I'm curious to see whether it is the same as the ones (#1-#11) covered by the linked MSDS.
I have to discard the emulsion. I will try it and see.
Maybe you can find a local scource for Nazdar 101 like the gentleman on dye transfer. There is a list of distributors on the nazdar website. http://nazdar.com/distribution.asp
Thanks for the David Doubley link... I've been to that website but didn't realize the quantity of excellent data there.
On the topic of sensitizer.. I'm not much of a chemist, but a chemist friend referred to the UltraStable sensitizer as Diazidostilbene Sulfonate. Is this just another word for the same stuff, or what exactly?
Perhaps a better method would be too look for a source for the raw chemical. I wonder if there are any DIY screen-printers or print-shops out there that make their own from scratch? IDK... but it's worth a shot.
If I wasn't swimming in projects to do, I'd dive in this with you guys. Has anyone checked out "Kosar, Light Sensitive Systems, Wiley, 1965" yet? Perhaps I'll sojurn to la biblioteca...
Ohh, also, I'd recommend that someone email Greg W. (dye-transfer OP) about this. He's a nice guy and would love to know that people are interested in this, I suspect.
This sounds familiar, essentially presensitised carbon tissue, just not the correct colours.
I picked up a copy before the holiday, and skimmed the section that CMB referenced. It's a bit over my head, chemistry-wise. I'll have to go through it again to see if I can glean anything useful from it.
Originally Posted by holmburgers
I'm hoping Charles or someone else following this thread can answer the following question for me:
In looking through one chemical supplier's catalog, I came across a number of very similarly named compounds. It's not clear to me how they differ from one another as a practical matter, what benefits/detriments the different variations have, nor how to determine which would be appropriate for this endeavor. Example:
4-DIAZODIPHENYLAMINE/FORMALDEHYDE CONDENSATE HYDROGEN SULFATE
4-DIAZODIPHENYLAMINE/FORMALDEHYDE CONDENSATE HEXAFLUOROPHOSPHATE
4-DIAZODIPHENYLAMINE/FORMALDEHYDE CONDENSATE HYDROGEN SULFATE ZINC CHLORIDE COMPLEX
The first one has the same CAS# (41432-19-3) as a widely-used screen emulsion sensitizer.
Originally Posted by mdm
The developer used for these films is a 2-part powder (hydrogen peroxide can be substituted for the developer). The page also refers to these films as being "iron-salt sensitized". This makes it sound more like the Chiba System than traditional carbon transfer.
I've just poured 2 rather imperfect 8x10 tissues made with different concentrations of diazo and should print with them in about 24 hours. I have stopped putting alcohol in my glop since I started coating with a rod and magnet wall, but had to do the 2 small ones with a comb in near darkness (not taking any chances), bubbles! Thats ok, they are destined for step wedges.
I dont see any reason why one could'nt brush sensitise dry tissue. May give that a try sometime too, though it comes with a time cost.
The 3rd chem on the list above looks good and it seems to be available from China at $28/kg (100kg minimum!) Also known as Diazo S or 4477-28-5 the difference of which is 4444, a good sign.
I hadn't even considered this aspect of things. I would guess it would work. My line of investigation come from looking for a sensitizer-incorporated tissue, because I wanted to avoid the time cost associated with sensitizing and waiting for the tissue to dry.
Originally Posted by mdm
If you do try brush-sensitize, please let us know how it works. Also, I've come across some references to diazo compounds that are soluble in alcohol (or maybe acetone), which would not be appropriate for a sensitizer-incorporated tissue, but could be appropriate for spirit sensitizing.
Well, I can confirm that it works fine.
I got 1 quart of kiwicol 225 emulsion which came with 7.6g sensitiser. Surmised that the poster in dyetansfer would have used sensitiser for 1 gal so extrapolated that and diluted mine with 22ml luke warm water. I used 2ml/50ml glop for an 8x10 tissue. 12g/l pigment, 60g/l sugur, 70g/l gelatine.
Used 1/2 my usual exposure and have a good 10 steps on a 21 step stoufer, obviously underexposed with no good black. It looks very much like 4 or 5% Ammonium Dichromate to me.
The catch, it stains everything that comes in contact with the tissue a strong yellow.
At this stage it is very expensive printing, but if it can be had seperate from emulsion and provided it clears ok, its the way to go.
PS the stain seems to be a charachteristic of RC paper, it does not stain much when you transfer to the back, or maybe I didnt mix it enough when I poured. In the Todd Gangler video it is a double transfer, the first transfer to albumen sized melinex or something like melinex, therefor stain is less of a problem. Where did I read how to clear it?
It is not as sensitive as AD, 3rd transfer=20 min exposure (still going), 1st was 3 1/2 min for 10 steps, 2nd was 9 min for 13 steps, no black. I have another tissue sensitised at double the rate to try.
20minutes is coming close to a good black, 15 steps. My normal exposure with digital negs and 2%AD is 9min, that would be contrastier than this diazo.
Ok, this is a quote from the ultrastable thread to keep it all in one place for me.
When all four colors have been processed and fully dried, residual
chemicals are removed by immersing the print in Clearing Bath A for
1 minute, followed by a brief cold water rinse and then placed in
Clearing Bath B for an additional minute. After a final rinse, the
print is dried and ready for finishing.
Stock Clearing Bath A:
Water (at 110 F) 930 ml
Potassium Permanganate 6 g
Sodium Chloride (Table Salt) 14 g
Stock Clearing Bath B:
Water (at 110 F) 940 ml
Sodium (Meta)Bisulfite 30 g
Sodium Sulfite 30 g
To make working solutions of A and B, dilute each in cold water at 1:20."
All of this is easy to get and the only thing I dont have are condes crystals
This is definately workable for colour and multiple transfer, not sure that the dmax is there even with stronger sensitiser strength.