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  1. #171
    Photo Engineer's Avatar
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    The problem is, I have no idea!

    Sorry.

    PE

  2. #172
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    Chris
    Have the stuff come to one location in the US where you will be.. let each person be responsible of picking it up and shipping issues. You could be opening yourself
    to a lot of grief/hassel otherwise.
    Bob
    Quote Originally Posted by Photo Engineer View Post
    The problem is, I have no idea!

    Sorry.

    PE

  3. #173
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    Well the plan at present is to ship the big order to me, and I will package and ship everything out myself; adjusting the price a bit to account for shipping/packing supplies and my time. My goal is to not raise the price beyond $200/kg (currently at $180/kg). This should be pretty easy to achieve.

    As for the liabilitiy of shipping, I guess the best I can do is offer USPS insurance and to make completely sure that this chemical is indeed legal to ship to wherever it's heading. Beyond that, we can't plan for anything outside of that. In the case of the aforementioned E6 guy; that was a mistake on the post office's fault, a freak occurrence if you will.

    I ship things all the time and have yet to have any serious problems; including international. The fact that it's a chemical does change things a bit, but we have to assume that the usual channels will function as their supposed to.

  4. #174
    holmburgers's Avatar
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    Just had someone PM me who is interested in using azide sensitizer for photogravure. I don't see any reason why it wouldn't work great for that, but wanted to see what others thought.
    If you are the big tree, we are the small axe

  5. #175

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    My understanding is that photogravure tissue is very similar in composition carbon transfer tissue. It's still gelatin...Don't see why it wouldn't work.

    --Greg

  6. #176

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    Quote Originally Posted by holmburgers View Post
    Well the plan at present is to ship the big order to me, and I will package and ship everything out myself
    Do you plan to repackage it from bulk? Then you will need UV blocking glass or plastic bottles and a black plastic bag per bottle.

    Also did you ask Secant if they plan to continue selling the CAS 2718-90-3, diazidostilbene in the future? It looks they are selling out this batch at a special price. If they stop this will be a dead end...

    Kees

  7. #177
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    That would likely be the plan; repackaging it from bulk. I've already started looking at amber PET bottles and that kind of thing. Doing it right will be my #1 priority.

    Here's what Secant says about this sensitizer; they have about 60kg left that they are selling it for a small markup over cost. After this, they said they're not sure about how much another manufacturing run would cost, but it might be in the $1000/kg range. That's still cheaper than say, Sigma-Aldrich or TCI. And there might be more of this stock elsewhere in the world(?). However, they basically don't know (or haven't said) what a mfg run would cost and hope that they can get their manufacturer to do it "reasonably."

    What's important now, in my eyes, is to get to know this stuff and develop as much knowledge about it as we can. 60kg is a lot, and this group buy will put more of this sensitizer in the hands of at-home-carbon-printers than ever before.
    If you are the big tree, we are the small axe

  8. #178

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    Quote Originally Posted by holmburgers View Post
    Doing it right will be my #1 priority.
    Excellent, I had no doubts about that! My own provision from another supplier was packed in a brown glass bottle within a black plastic bag. Same kind of bag as we know from photopapers. Brown glass or brown PET probably doesn't block enough UV. Dick Sullivan somewhere mentioned special UV blocking bottles he used. Not brown but opaque white.
    The powder itself is light sensitive so all handling should be done with safe light.

    Quote Originally Posted by holmburgers View Post
    60kg is a lot, and this group buy will put more of this sensitizer in the hands of at-home-carbon-printers than ever before.
    Yes, and after that we probably have to go to China for more.... I'm still interested to know about Secant's Eastern European manufactures.

    About quantities:

    Carbon tissue with diazidostilbene incorporated needs a gelatin/diazidostilbene ratio of 0.04 - 0,06. The 0.06 ratio equals the behaviour and printing time of 3% dichromate sensitized tissue. With a lower ratio contrast gets higher, sensitivity lower, nothing new.
    So for every liter of 10% glop you need 4 to 6 grams diazidostilbene. With a kilo one can make 166 to 250 litre of glop. This coats 237 - 357 square meter tissue with a 0,7 mm wet height. A square meter can be cut down to twenty 8x10inch tissues. A kilo is good for at least 4740 8x10 prints. One has to have a serious production workflow!

    -k

  9. #179

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    clearing

    Another remark about clearing:

    I have been doing mostly double transfer, where clearing is not a big problem as the image is transfered to a polyester support and seems to wash much better. This is different with single transfer to a paper. Yellow stain in the paper is visible when the print is dry. When the print is not properly washed as happened to my students last weekend it is even worse.

    The original Ultrastable method used a white polyester base sheet for the final print. Apart from easier registration, clearing might be one of the reasons for using polyester for single transfer.

    I could clear the single transfer prints on paper with the normal permanganate/ sulfite-metabisulfite method, but they had to stay much longer in the sulfite bath. On one print a little yellow tone in the paperwhite is still visible.

    So if you only do single transfer this might be an issue. Maybe there are other efficient clearing agents though.
    By the way: I kind of like double transfer now. Not that difficult to start with and very easy once used to it.

    -k

  10. #180

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    I had a chance to meet Tod Gangler yesterday at Alt-Photo Pacifica, and pick his brain a bit. I found him to be quite generous with his time and knowledge.

    I learned a few things from him that I'll be writing up the next couple of days. Coincidentally, on the Yahoo carbon list, Sandy King had asked about how light sensitive this process was with regards to handling both the raw sensitizer and the finished tissues. Since I have that written up already, I thought I'd share that first.

    Apologies if you've already seen this on the Yahoo list.


    The sensitizer is most sensitive as a dry powder, decreases as its put into
    solution and added to the emulsion, and is even less sensitive in the dried
    tissue.

    Tod's recommendations for maximum light levels were thus:
    -- Red safelight only for weighing the powder and adding it to solution.
    -- Safelight + very dim 60W tungsten (as low a setting on a dimmer as
    possible to get it to light) for adding to the emulsion.
    -- A 60W bulb mid-way on a dimmer for pouring the emulsion. He uses a slightly
    lower level for black and yellow, since his pigments are more prone stain, so
    minimizing fog is first-priority. Slightly higher levels for cyan and magenta
    because they are less prone to stain. This may vary depending on the exact
    pigments that one might use.


    I'll add this from my own experience: Pouring tissues onto clear substrate in red safelight conditions is frustrating if you're not using some sort of frame. Pouring onto a yupo-type material, as Tod does, might be easier because it's easier to see the edges of the substrate. I've taken to outlining the tissues (which are squeegeed onto glass) with a silver sharpie. Much easier to see the edges that way. I may consider switching to a Yupo-type material, much as I like using the Dura-Lar.

    --Greg



 

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