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  1. #11

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    For tissues, try upping the sugar in the pigmented gelatin a little or adding some glycerin to it. I use 3 mil drafting mylar for the tissue support, which is very thin and doesn't curl as it dries. I also press the tissues in a yupo binder after the tissues are thoroghly dry to flatten the further. I tried yupo for the support but I couldn't get it to lay flat for coating without it 'popping' in the center and ruining the uniformity of the tissue.

    If you're simply having problems keeping the tissue support flat during coating, mist the work surface, then firmly squeegee the support to it before pouring the pigmented gelatin.


    Also- here is a wonderful carbon printing forum-http://bostick-sullivan.invisionzone.com/index.php?
    Last edited by Colin Graham; 07-04-2008 at 09:33 AM. Click to view previous post history.

  2. #12
    q_x
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    Thanks Colin! The link - very interesting!
    Paper curls when dry, not while coating. Making even coats is not so big problem if I'm doing this fast. I'm adding lots of sugar (about 1/5 to the gelatin). I'm also squeezing the tissues when dry - once before and once after sensitizing it.

    Meantime I've made some progress

    Yupo wasn't in the shop. "No sintetic papers, cotton only".

    I've tried once more with the heavyweight paper and 0,75 mm thick 25% gelatin - it was good, almost acceptable.

    And here is the bomb:
    I've tried 2mm thick white "cardboardish" plastic sheet (it is sometime used to cut the letters in, or as a banner support with some print/cut-out glued on it). It was easy to coat it with satisfying coat. After drying (no heating, just waiting the 20 hours) the gelatin tissue and the supporting sheet can be easily separated. First time I've seen such a thing! I can take the tissue and with a little help of water - glue it where I want - with the bubbleless, dust-free side to the support.

    Thanks all for support.

    Cheers,
    Luke
    Use the Force, Luke!

  3. #13
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    Luke;

    The plastic is not subbed. All plastics repel gelatin in water and so when dry, they can be separated. Yupo and all conventional film supports are subbed to prevent separation when dry or wet.

    PE

  4. #14

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    Well, I certainly gave up too easy on Yupo- I tried it again last night and it works quite well. Lays flat while coating and the rigidity of the plastic helps the tissues to dry much flatter than the mylar.

    I forgot to mention to be careful with the glycerin if you do use it- a little goes along way. If you're in a humid climate probably better to avoid it altogether, the tissue may never dry completely. I tried using 10ml/liter here (western Washington) and the tissue was still sticking to the negative after 3 days.

  5. #15
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    I recently took a carbon workshop with Vaughn up in Hayward,Ca. He showed us a trick. After you pour your tissue and it has set up a bit transfer it to a piece of cardboard and put a bit of the leftover glop on each corner and push a pin in the corner to hold it flat. Dry hanging with a fan on it. His tissue that we used at the workshop was nice and flat.

    Jim

  6. #16
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    I believe that sorbitol can be used in place of glycerine and it has less tendancy to dry tacky, but it still can if you use too much.

    PE

  7. #17

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    I use Yupo as the support for carbon tissue. It is the single best support I know of, and if you use the light weight material it is reasonably economical. Most carbon tissues will curl when dry unless you store them flat as soon as the tissue is dry. I dry my tissue oin screens and as soon as it is dry I transfer it to a holding box where it is kept flat. If you leave the tissue lying around, or store it in a roll, it will curl severely, especially in dry climates. Glycerine should be avoided except in very dry climates as tissue that contains cglycerine can be very slow drying after sensitizing.

    Sandy King

  8. #18
    q_x
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    Thank you all! You are very helpfull and supportive.

    I don't use glycerine. It is worm and humid now (25C, raining). I add only sugar (and soap in some rare experiments).

    I've made myself magnetic stir plate - nice and cheap tool. But how to heatglass on this in el-cheapo way?

    PE: In fact: separated gelatin tissue is almost useless.

    Offtopic: have you tried to use glass to make your coating blades? AFAIK glass is much easyier to work with it than with metal when high precision is a must.

    Jim: I've tried to hold the paper (120g Fabriano Accademia) with clamps. It is usable, but curled at the edges. And it is torn at one corner (huge forces while drying did this). I'll try pinning onto cardboard.

    Sandy: I store the tissues flat under heavy weight. I've managed to made some of them uncurled enough to be
    usable in most areas (edges and corners are stubborn, but maybe this is the way it should be). I will look for Yupo or some surrogate. I live in 500k city, I've tried to find yupo in the most popular shop here - no chance. I'll try in other shops. Perhaps I'll ask some of my friends to buy it on holidays. Or I'll buy glass. Should be cheaper (not cheap :/ ) and usable too. Maybe I'm patient enough to coat very few sheets at once.

    Thanks for helping. I'm going to shut up and try all the methods mentioned above. I'll post results after ending.
    Cheers,
    Luke
    Use the Force, Luke!

  9. #19
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    I coat thickly onto used litho film (.004" thick), then use push-pins to attach it to a piece of cardboard to dry. I use a little of the excess gelatin mixture under each corner to "cement" the tissue to the cardboard. The tissue can not curl. I brush (spirit) sensitize the tissue right on the cardboard and dry for an hour or two with a fan. The dried, sensitized tissue does not curl when removed from the cardboard.

    Vaughn

    PS...sorry did not notice that there was a second page of responses. I find the edges curling up a bit to very helpful when spirit sensitizing -- the curl keeps the sensitizing solution on the tissue when one is brushing it around. And it is not necessary to evenly sensitize the edge -- since there will be no image there as it is the "safe edge" -- I have a 1/2", or 12mm, safe edge.

    I have some Yupo that I bought many months ago -- I'll have to give it a try one of these days! I imagine that the Yupo would act very similar to the used litho film since both are non-pourous, non-paper material.
    Last edited by Vaughn; 07-16-2008 at 04:08 AM. Click to view previous post history.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  10. #20
    q_x
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    Any LF film - I'll try it as soon, as I find it. I've lost few 30x40 cm sheets somewhere.


    Thanks for helping me. It is good to find helpful people. I have some background in gum bichromate printing (and working with paper in general). This tissues are still really big quest, adventure and challenge for me.

    Here is the summary of this whole action.

    What was my goals:
    To start making cheap and really high quality custom carbon tissues.
    Do this in one, fast, non-complicated way for both small (postcard) and large (A3 and bigger) formats.
    Do this without making too much mess in my new small flat.
    Coating several tissues at one time.

    Not all actually are of equal importance.

    What I've been testing:

    Two papers:
    Fabriano Accademia 120g, acid free thin sketch paper. It is thin, so it was good indicator if the method is good.
    One side coated offset printing paper 170-200g, standard paper used eg. to print postcards.
    Hot-bathed or simply wet when needed

    Edible gelatin (mostly with bloom 150-170, other was weaker), various artist's pigments in powder form (from Kremer).

    And some methods - and the result (after coating, drying, wetting - in place of sensitizing - and drying again):
    1. Coating paper with fingers or bar within frame - lots of mess and things to wash, paper had uneven coat and was curled after this; maybe this is the good way, but not for me or not in the moment or not with the papers.
    2. Coating paper (edge to edge) with fingers - less messy, paper almost 100% usable (curled edges).
    3. Coating paper with crude PE-style blade - thicker paper is usable when coated with strong gelatin solution (25-30%), but with strong solution bubbles and dust are serious problem. It is possible to coat only one tissue at a time. After this I had to wash and dry the blade.
    4. Coating paper with silkscreen half-pipe coating tool - very messy, it was hard to control the coating. Good results, but most of gelatin solution was wasted
    5. Coating PE-LD sheet (2mm thick white matte plastic) with fingers (with or without putting paper on this) - the result was always tissue separated from support. Unusable unless I want to produce carbon "instant pasta". Paper curled taking gelatin with it.
    6. Coating glass with fingers - very good. Haven't tried to use this to print something - I don't want to use dichromate in old flat, but should be OK.
    7. Coating glass with fingers and cover it with paper - it is hard to avoid air bubbles within gelatin and paper with larger sheets of paper (or destroying coat while getting rid of the bubbles). I was also unable to separate tissue and glass after drying.
    8. Coating plexi with fingers - act as glass if the gelatin is sweet enough and stronger than 10% and surface is clean. Traces of lipids/fat are hard to cover with gelatin
    9. Coating plexi with fingers and cover it with paper - after drying it is easy to lift the gelatin and separate tissue and plexi. Very good for smaller tissues (postcard size).
    10. Methods with covering back of paper with gelatin - not so good results for me. When paper was not flat - I was unable to coat it on the other side. When it was flat before coating - it was curled after. Too much effort for the simple thing. I'll try this with sized paper - as for gum bichromate.
    Dip-in the paper - unable to dry even layer of gelatin. I will try this in winter, gelatin will set within seconds.

    Conclusions/thoughts/ideas for now:
    Soft toilet paper is good weapon against big bubbles.
    Big syringe is my big friend.
    YUPO is unavailable in Poland, it is easier to see polar bear than YUPO in shops here.
    It is very hard to coat thin paper (but isn't using thick paper a waste?)
    Using glass or plexi (but not PE-LD) in place of paper is cheaper, both can be used hundreds of times. Plexi is easy to scratch and not so-so in hot water, glass is easy to break. Both are available.

    I think after moving to the new flat I'll save some money and buy few sheets of glass between a4 and a3 size (I have trays 45x32cm) and make lightproof rack'o'cabinet to dry it with blown-in dust-free air. I think computer fan powered with old cellphone charger and some muslin, nylon or gauze filter will be working good enough. Nice if top of the cabinet also could be used as coating and printing table.

    Cheers
    Use the Force, Luke!

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