Diazo-Sensitized Carbon Transfer

[phritz phantom]

For the 2 chemicals I received samples of, and based on the MSDS sheets I received with them, I would say that handling them poses no greater risk to human health, than say, handling selenium toner powder or dichromate powders. Appropriate care should be taken to protect your eyes, skin, respiratory tract and other mucous membranes from airborne dust and direct contact. As always, it is up to the individual user to review all safety information regarding a specific chemical or process, and take all necessary measures to protect oneself.

--Greg

but the lower toxicity is one of the main points to switch from the dichromate. or at least it is for me, since i'm looking for something i can use in my improv-dim room with less of a headache.

i just checked the MSDS for the "hardener no.3" substance from TCIEurope and it's listed as "flammable solid- cat. 2" and "acute toxicity oral/dermal/inhalation - cat. 4".
4 is the lowest possible category. this should be quite an improvement to the dichromate.

unfortunately i couldn't find anything at Omikron, the place in germany where i can usually order strange chemicals from . i'll email foto suvatlar- a small chemistry shop specialized on photo stuff - who has been very helpful to me in the past. maybe they can come up with something.

thanks a lot for posting the results for the second speedball batch. i'll skip the stuff then and order something from kiwo for first experiments.

 

[holmburgers]

Just to save someone the leg work...

U.S. Patent 3,721,557 - Method for Transferring Colored Image and Light-Sensitive Transfer Sheets Therefor - Nobuyuki Inoue for Process Shizai Company Ltd. - March 6th, 1969

 

[phritz phantom]

if you search for "(Noriaki) Tochizawa" in the google patents engine, that guy is involved in a lot of patents about the topic we are talking about.
http://www.google.com/search?q=tochizawa&hl=en&tbo=1&tbm=pts&ei=llhFTtG2K4TLtAbb_di7Bw&start=0&sa=N

 

[gmikol]

It worked!!!

...sort of.

So here's a little progress update.

I got 25g samples of

4-Diazodiphenylamine/formaldehyde condensate hydrogen sulfate zinc chloride complex (CAS 68988-17-0)

and

4,4'-Diazidostilbene-2,2'-disulfonic acid, disodium salt, tetrahydrate (CAS 2718-90-3)

from Secant Chemical about 2 weeks ago. They were shipped in heat-sealed foil packets, each in a zip-top bag, in a bubble-wrap mailer. They were shipped UPS 2nd Day Air from Massachusetts to Washington State. I am keeping them stored in the refrigerator.

Based on (there was a url link here which no longer exists) from CMB, I mixed up my standard recipe of (high-relief) glop, and added the same amount of diazidostilbene sodium sulfonate as I would have used dichromate (approx. 2 mg / in^2 of tissue).

I'll get a scan of the step wedge up in a day or 2, but here's what I've found so far:

--It's about 1/2 to 1 stop slower than the comparable dichromate-sensitized tissue, but with a much longer exposure scale (about log 3.0). This is 600-800 units on my NuArc. 800 units is about 20-25 minutes, which gets to be a little hot.

--I'm not sure this is suited for high-relief tissues, as there were a fair number of micro-bubbles, more and larger in the darker areas. I belive that the azide compound gives off nitrogen when it decomposes, so that might be causing it. In the lighter areas (thinner gelatin layer), the bubbles were less-pronounced. My next test will be with a thinner, more heavily-pigmented tissue.

--An un-exposed tissue was exposed to incandescent light (2 x 100W in a 6x9 foot room) for 2 hours without any noticeable fogging, so it's probably safe to handle dry tissues without use of a safe light. CMB has alluded to the compound being more sensitive in solution (there was a url link here which no longer exists), so I don't know about making/pouring the glop. (For this batch, I used a red safelight).

I do have one unknown, still. I would prefer to have more speed on these tissues. If the diazidostilbene sodium sulfonate behaves the same way as dichromate, then I've got a problem. More sensitizer = more speed, but as the exposure scale goes beyond 3.0, it becomes very hard to create negatives for this process, even with litho film or xray dupe film. Hard-dot screened imagesetter negs might work, but not on this forum .

I'll be sure to post more as I learn more.

--Geg

 

[mdm]

Sensitivity is not much of a problem with cmyk as exposures are much less than with B&W.

Any yellow stain?

 

[holmburgers]

Greg,

This sounds very cool!

Would you concede that a reduction in speed is made up for by having presensitized "ready to go" tissues though? Then again, heat is a concern.

Do you plan to repeat the same test with CAS 68988-17-0 to see how they compare?

 

[gmikol]

Well, as mdm suggests, exposure times for separations would likely be much less. Using CMB's target of 1.24 logD for the black UltraStable tissues would probably mean at least 2 stops (if not 3) less exposure that what I did. So for separations, you're right about the trade-offs, pre-sensitized definitely wins. But I'd also like to use pre-sensitized tissues for B&W work, as well. In this case, sitting around for 20 minutes waiting for something to print is a bit of a PITA.

I plan on making a test of the other sample eventually. It was similar enough to what mdm used, that I wanted to try the other one first. I only get little bits of time here and there over the summer, so it might be a while before I get a chance. I hope to get more time once the fall settles in.

--Greg

 

[holmburgers]

I agree, it'd be nice to completely eliminate dichromates for b&w too. For what it's worth, my exposures with 2 CFL black lights can be about an hour long...

 

[gmikol]

Well...I'll acknowledge the possibility that the bulb in my NuArc NL22-8C is at the end of its life. It's the bulb that came with it when I bought it used, and I have no idea how many hours it has on it. I have a replacement, but in an attempt to protect the upper safety glass from shifting / breaking since it gets moved a lot (don't ask), I added nuts to the locating studs. Problem is, now I have a big dis-assembly project to get at the lamp assembly. Don't know why I didn't replace the lamp when I had it all apart...

--Greg

 

[gmikol]

Any yellow stain?

mdm's question is in regards to use of diazidostilbene sodium sulfonate.

The answer is yes and no. And that it seems to depend on the paper used for final support.

The sensitizer itself in solution is nearly clear, and does not seem to have an intrinsic stain, like the diazo sensitizers that have been discussed earlier in this thread.

On my first test, I used a microporous inkjet paper, which i use sometimes for quick-and-dirty tests, to avoid using up my fixed-out photo paper. It has a tendency to show stain readily (even with dichromate and cyanotype), and it did. There was a significant brown stain that appeared within 2 hours of development and drying.

The second test was on fixed-out FB paper, and it only started to show very faint stain about 12 hours after drying.

Both were cleared about 36 hours after drying, using the formula posted earlier in this thread and in the UltraStable thread. Both cleared readily, without the frilling and emulsion damage that mdm reported in his tests.

Can anyone reading this thread explain the chemistry of clearing these prints, especially the role of the potassium permanganate? For reference, the formula can be found (there was a url link here which no longer exists).

--Greg

 

[holmburgers]

Can anyone reading this thread explain the chemistry of clearing these prints, especially the role of the potassium permanganate? For reference, the formula can be found (there was a url link here which no longer exists).

--Greg

+1

----------------

Inkjet papers contain dye mordants much like dye-transfer paper, which is what I transferred a q&d Ultrastable test to. Like your experience, a brown stain appeared in the next couple hours.

I have seen these compounds (diazo/azido) referred to as dyes before.

If your fixed-out FB paper was treated in a hardening fixer containing chrome alum or the like, you could expect this to have a mordanting effect as well, though significantly lower. It therefore might be interesting to observe what happens with photo-paper that was fixed out in a non-hardening fixer.

 

[Photo Engineer]

Greg;

The Potassium Permanganate is a powerful oxidant which is probably there to destroy all of the residual organic chemicals in the coating. The second solution contains Sulfite which is probably there to scavenge any remaining Permanganate.

PE

 

[gmikol]

Thanks, PE, I suspected as much, but it's nice to have a little confirmation.

This brings up another question, though, and not just directed at PE.

It seems like we're transfering all of the health and environmental handling concerns from the dichromate to the permanganate. If one of the goals is to come up with a carbon process with fewer potential risks to human health and the environment, it seems like an alternative clearing solution should also be investigated. Would a strong hydrogen peroxide solution (say, 10%) serve a similar role?

--Greg

 

[gmikol]

If your fixed-out FB paper was treated in a hardening fixer...[snip]...It therefore might be interesting to observe what happens with photo-paper that was fixed out in a non-hardening fixer.

The paper I used was fixed-out in a non-hardening fixer (Ilford Rapid Fix). The stain that developed was very faint (but noticeable) compared to your example and my first test, and took much longer to form.

--Greg

 

[holmburgers]

It seems like we're transfering all of the health and environmental handling concerns from the dichromate to the permanganate.

That's a very good point, but if you look at the clearing formula A, it is a 0.6% solution of potassium permanganate which is then diluted 1:20 for use.

If we assume we're using a tray and a big print, requiring 1 liter lets say, thats only 0.3225 grams of K-permanganate, whereas a K-dichromate tray sensitizer could require as much as 50 grams.

 

[Photo Engineer]

You will have to test alternatives yourself. I have no idea what will work well. See the other similar train of posts.

PE

 

[gmikol]

If one of the goals is to come up with a carbon process with fewer potential risks to human health and the environment, it seems like an alternative [to a permangante] clearing solution should also be investigated. Would a strong hydrogen peroxide solution (say, 10%) serve a similar role?

I'm cross-posting this from the UltraStable thread, since it's relevant here, too:

I just tried hydrogen peroxide. Some web reading suggested that it's oxidizing ability was enhanced in acid solutions. I only had 3% stuff around (drug-store H2O2), so here's what I tried:

100mL 3% H2O2
~1mL 40% citric acid solution (this is about 0.4g).

It created a just-noticeable lightening of the dye stain in an all-white area (drop test) after about 90 seconds contact. Perhaps if you can easily get your hands on 10% or stronger H2O2, it might be a viable option, and one that eliminates the need for potassium permanganate.

--Greg

 

[CMB]

Exposure Times

--It's about 1/2 to 1 stop slower than the comparable dichromate-sensitized tissue, but with a much longer exposure scale (about log 3.0). This is 600-800 units on my NuArc. 800 units is about 20-25 minutes, which gets to be a little hot.

Geg

Typical exposure times for the UltraStable Color pigment films in a 26-1K plate burner ranged between 3 to 5 minutes. The need for a 25 minute (or more) exposure time baffles me. The Hardener No.3 absorption peak is 335nm and perhaps your light is emitting little energy of that nature. Alternately, the problem may be sensitizer (concentration, mixing technique or ?) related. Here's an example of how the sensitizer was incorporated into the UltraStable materials:

To make 250 ml of emulsion:

1. Add 1.5 g of Hardener #3 to 50 ml of water at 85F and QS to 60ml.

2. Slowly add sensitizer prep to 190 ml of a 13% pigmented gelatin prep at 105F.

Hope this helps..

Charles

 

[gmikol]

335nm peak? Really? That's not a typo? I thought that soda lime glass didn't transmit much below 350nm.

A couple other observations on my part:

-- My NuArc NL22 uses the same bulb as the newer 26-1KS (NP80). This is different from the bulb that the 26-1K uses (GW114). Not sure exactly what the difference in terms of output spectrum is.

-- My NuArc bulb is pretty old.

-- I only used 250 mg of hardener, to make ~160 mL of emulsion, about 11% final gelatin solution. Sounds like I could quadruple sensitiser strength.

What was the typical density range of a negative for use with UltraStable?

--Greg

 

[CMB]

The 335nm absorption peak description is from the Hardener #3 spec sheet. As you state, glass cuts off most of the UV transmissions at this level. Metal halide or mercury vapor lamps used in graphic arts platemakers typically have a peak of 365nm and so there is still quite a bit of usable energy reaching the films within the spectral region to which they are most sensitive. I have found that while an old lamp may seem to burn brightly, much of its actinic light output can be severely degraded.

Typical con-tone separation negatives have a density range of 1.20 - 1.60 and are developed to a gamma of .75

I suspect that increasing the amount of sensitizer may go a long way towards reducing your exposure times.

 

[Photo Engineer]

Two UV ranges are recognized in photography. UVA and UVB radiation are their common designations. One is from about 350 - 400 nm and the other is shorter than 350. UV lamps are often sold in these two categories. You would have to match the lamp to the peak sensitivity of the light sensitive material.

PE

 

[keesbran]

I found the 4,4'-DIAZIDOSTILBENE-2,2'-DISULFONIC ACID DISODIUM SALT tetrahydrate, 99%
CAS: 2718-90-3 available at my supplier in the Netherlands.
Does anybody know what the keeping conditions and shelf life of these diazo salts are? They are rather expensive, compared with dichromates and ordering more makes them a little bit cheaper. But still around 1€ per gram.

Kees

 

[gmikol]

I'm away from my notes for a few days, but if I remember correctly, the info I got from my supplier in the US had a 1-year storage life at 20C, and 5 years at 5C. It came shipped in a vacuum-sealed foil packet, so I transferred it into a glass jar which I keep inside a black photo-paper bag inside the refrigerator (labeled, of course). The powder is sensitive to light, though I have not tested how sensitive it is.

It also seems to be a bit hygroscopic (absorbs water vapor from the air), so I'm going to get a silica gel packet to put in the jar for the next time I open it.

1 euro per gram is pretty good. The other EU supplier I had found was > 2 euro per gram.

--Greg

 

[keesbran]

1 euro per gram is pretty good. The other EU supplier I had found was > 2 euro per gram.

I received my first order CAS: 2718-90-3 today! I will try to coat some transfer sheets next week.

Charles if you read this, does the original Ultrastable recipe contain other special ingrediënts like surfactants or conservation agents?
And how about sugar/glycerin/alcohol (amounts) or other plasticizers in the pigmented gelatin?

Kees

 

[CMB]

does the original Ultrastable recipe contain other special ingrediënts like surfactants or conservation agents?
And how about sugar/glycerin/alcohol (amounts) or other plasticizers in the pigmented gelatin?

Kees

The "recipe" for the UltraStable pigment films is based on (except for the sensitizer) the formulation published in "The Home Manufacture of Materials for Carbon Printing" ( Wm. D. Fleming, American Photography, Vol 32, 1938, August, No. 8) :

Gelatin (20%) 100 ml
Sugar 5 g
Glycerin 1.5 ml
Pigment 1-5 - 2.5 g
Thymol (10% solution in 95% alcohol) 5 ml

Water (to make) 200 ml Total

Surfactants were added to the emulsion to facilitate machine coating but are not necessary for hand-made materials.