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  1. #141
    Photo Engineer's Avatar
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    If they have 60 kg, it must keep better than I thought.

    PE

  2. #142

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    Quote Originally Posted by CMB View Post
    To incorporate hardener #3 into a gelatin emulsion, 1.5 g/250 ml is a good place to start.
    Charles
    This worked very well for me
    I used a 10% gelatin solution, it makes a gelatin/diazidostilbene ratio of 0.06 (6 grams per 100gr gelatin, or 1 gram per 16,7 gr gelatin used).
    I'm currently experimenting with a lower ratio of 0.04.

    kees

  3. #143
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    Ok, received word back from the aforementioned supplier.

    I'm told they can supply it at $180/kg. That comes out to 18¢/gram!!

    Now, I'm not ruling out the likely possibility that this is a typo and that he meant $1800/kg. Regardless, that's still an excellent price at $1.80/gram. I will clarify this and report back.

    So, how to proceed? If by some miracle it really is $180/kg, I think that organizing a significant group buy could be easily done. Even at $1800/kg I think we can get some people in on this.

    What venues should we explore for organizing a group buy? APUG, the Yahoo! Carbon Transfer group, Bostick & Sullivan, ____(??)...
    If you are the big tree, we are the small axe

  4. #144

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    Quote Originally Posted by holmburgers View Post
    Ok, received word back from the aforementioned supplier.

    I'm told they can supply it at $180/kg. That comes out to 18¢/gram!!
    Is this price quote from Secant? It would be amazing if true. I would go for the kilo!

    Kees

  5. #145
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    Yes it is. I know, it definitely seems too good to be true, but *fingers crossed*...
    If you are the big tree, we are the small axe

  6. #146
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    Ok, stop the presses. The price is indeed $180/kg.

    I am still communicating to get the specifics (like shipping, etc.), but this seems like a really great opportunity to get this stuff at an unprecedented price. I think that at this price it should be possible to find enough interest for several kg's. I mean, I too would would consider buying one for myself, and I suspect more might feel the same way. It should be noted that there is only a quantity of 60 kg or so total, and that this represents a previous manufacturing run. The industry demand is different now and subsequent production would be on a smaller scale and thus, more expensive. This is what I was told.

    So, we need to do some organizing here methinks. Greg, Kees, anybody else, are you guys in? Why don't we convene through email and start a chain to figure out some of the specifics. Logistically, this shouldn't be too difficult, but a concerted effort is probably necessary. I would greatly appreciate any help, and could definitely use it! There are a number of things to consider, like enticing others, handling the money, handling the product and shipping. Sandy King has done group buys in the past and he might be someone to consult on this; not to mention he might be interested in this diazo compound. Alternatively, the Photo Formulary might be interested (and better suited) to brokering this deal, so to speak.

    Let's make it happen!
    If you are the big tree, we are the small axe

  7. #147

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    (EDIT: Looks like holmburgers beat me to the follow-up...Chris...you've got my email...)

    Secant quoted me $300/kilo last year. If their demand has fallen off and / or they're looking to clear stock, it's not surprising they've lowered the price.

    You should also see if they'll give quantity pricing on smaller packaging units (like 100 gm, which they quoted me @$75 last year) if we got an order of >10 units (1 kilo) together, so that no one has to worry about re-packaging from the larger container. Even if the cost / gram is more, it's a lot less work.

    As for the group buy, don't forget DPUG (is there anyone here not reading both, though?), and the alt-photo-process list. In theory, this should work with gum as well, though it sounds like Kees didn't have any luck with his initial testing... Maybe the large-format forum (http://www.largeformatphotography.info/forum/), but then again there might be a lot of overlap between there and here.

    Group buy would probably only work for USA, though. I'd guess there are too many headaches trying to ship chemicals cross-border.

    --Greg
    Last edited by gmikol; 09-10-2012 at 07:36 PM. Click to view previous post history.

  8. #148

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    Just wanted to follow up and add a point to get people thinking about what quantity they might want.

    Charles Berger's guidelines for about 1.5g of sensitizer per 250ml of finished glop means 6g per liter of glop.

    Based on some experiments I made last year, it doesn't seem like you'd want to pour thicker than 0.5ml per in^2 (and possibly thinner), so 50ml of glop for a 9x11" tissue. So that 6 grams of sensitizer would yield at minimum 20 9x11" tissues. 100 grams (~320 9x11" tissues) could be a pretty significant supply for many people.

    Why not thicker than 0.5ml per in^2 (with about 11% gelatin)? Thicker than that, and the nitrogen that's given off by the azide breaking down can't escape all that well, and you end up with all sorts of little pinhole bubbles in the dark areas after mating and development (you can't see them in the dry tissue).

    --Greg

  9. #149

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    One more thing...

    Anyone considering using this sensitizer should keep in mind that the prints need to be cleared with a specific clearing bath that Charles Berger has posted here.

    One of the chemicals, potassium permanganate, is a powerful oxidizer. It is available from the Formulary and B&S, but larger quantities >30 grams are subject to Haz-Mat fees. But 30g will make 5L of stock solution (100L of working solution).

    Just FYI...

    --Greg

  10. #150

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    It sounds wonderful! When you order, I'd like to get 100g of sensitizer. Add me to the list if there is one.



 

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