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  1. #71

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    Phritz--

    At the risk of being rude, did you read this thread?

    In brief summary:

    --The use of Speedball sensitizer is discussed in the original post to this thread, here.

    --2 possible sources for "Hardener #3" (Diazidostilbene Sodium Sulfonate, or 4,4'-Diazidostilbene-2,2'-disulfonic Acid Disodium Salt, CAS: 2718-90-3) are identified here.

    --I mention having ordered samples of Diazidostilbene Sodium Sulfonate here. Though I have not had an opportunity to test it, yet.

    I have not been able to track down the CAS# of the ND22 sensitizer identified on the B&S board, from PJS Chemical. But I have received a sample of a close chemical cousin, 4-Diazodiphenylamine/formaldehyde condensate hydrogen sulfate zinc chloride complex (CAS 68988-17-0), also not tested yet.

    The families of chemicals discussed here (diazos and azides) are capable of polymerizing a great number of things, including gelatin, and are most likely capable of doing so with gum and casein, though I don't know of anyone who has made those efforts.

    In principle, any molecule that has received enough UV energy to contribute to image formation will stay in the gelatin. Anything that did not react will either come out in the development and washing process, or be removed by the clearing bath, discussed here.

    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.

    My brief summary turned out to not be so brief, but I hope this helps.

    --Greg

  2. #72
    mdm
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    Thanks for your work.

    I made some cmyk transfers onto albumen coated mylar a while back with my screen printing sensitised tissue, but at 3.5 min exposure I did not get enough density (close though) and the yellow transfer was very thin, so maybe yellow needs more exposure even than black, I was using the edge of an A3 tissue though so that could be the cause. Also it stains the cyan tissue so much that it looks green. I will be interested to hear how the stuff you have works and if it is strongly yellow staining.

    This is now my busy period at work so things have stalled and wont progress for a few months.

    David

  3. #73

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    Quote Originally Posted by gmikol View Post
    Phritz--

    At the risk of being rude, did you read this thread?
    sorry, yes i did. but i just spent about 12h in front of the computer reading about diazo and the ciba system and in between trying to locate the mentioned products in various european mailorders. thanks for your patience.

    i confused you and mdm and thought the whole initial part of the thread was about the kiwocol 225 sensitizer (which was proven as working later on).

    did you do another try with the speedball after the first? i couldn't find anything.


    --2 possible sources for "Hardener #3" (Diazidostilbene Sodium Sulfonate, or 4,4'-Diazidostilbene-2,2'-disulfonic Acid Disodium Salt, CAS: 2718-90-3) are identified here.

    --I mention having ordered samples of Diazidostilbene Sodium Sulfonate here. Though I have not had an opportunity to test it, yet.

    I have not been able to track down the CAS# of the ND22 sensitizer identified on the B&S board, from PJS Chemical. But I have received a sample of a close chemical cousin, 4-Diazodiphenylamine/formaldehyde condensate hydrogen sulfate zinc chloride complex (CAS 68988-17-0), also not tested yet.
    you've received it, but not printed yet? great, please post results.
    i'm ordering from europe, so those two sources most likely won't work for me. pjs might though. when the stuff has been proven usable, i'll try and locate some around here.

    speaking of which, has someone thought about contacting a screen printing supplyer with the patent informantion on "hardener no.3" and if they could say which one of their sensitizing solutions is closest to that formula? the same with pjs.
    i could try and email kiwo, since they are a german company, afaik.
    Last edited by phritz phantom; 08-11-2011 at 10:12 PM. Click to view previous post history.

  4. #74

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    Quote Originally Posted by phritz phantom View Post
    did you do another try with the speedball after the first? i couldn't find anything.
    Yes, I made a second try, but did not publish any results. It was another failure, but this time, there was absolutely no image formation. The tissue dissolved completely after mating. I used the same sensitizer I had put into solution for my first test, but considerably less. Seems like it lost all sensitivity. I suspect that the Speedball sensitizer is not stable enough for this application. I will not be making any more trials with it.

    Quote Originally Posted by phritz phantom View Post
    ...trying to locate the mentioned products in various european mailorders...
    One of the suppliers in the US I looked at also has a European division:

    TCI Europe

    Not the best pricing, but it's a start.


    Good luck--

    Greg

  5. #75
    CMB
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    Quote Originally Posted by gmikol View Post
    Phritz--

    The families of chemicals discussed here (diazos and azides) are capable of polymerizing a great number of things, including gelatin, and are most likely capable of doing so with gum and casein, though I don't know of anyone who has made those efforts.

    --Greg
    USPatent 3,721,557, which discusses light-sensitive color transfer sheets, specifically mentions the ability of diazos and azides to polymerize casein as well as other hydrophilic polymers such as gelatin.

    The Patent also lists a number of compounds (in addition to Hardner #3) which have this capability. It also provides an extensive list of color pigments which can be used to make the color sheets.

  6. #76

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    Quote Originally Posted by gmikol View Post
    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.

  7. #77
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    If you are the big tree, we are the small axe

  8. #78

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    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=tochi...w&start=0&sa=N

  9. #79

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    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 this tip 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 (link), 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

  10. #80
    mdm
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    Sensitivity is not much of a problem with cmyk as exposures are much less than with B&W.

    Any yellow stain?



 

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