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  1. #1
    Mustafa Umut Sarac's Avatar
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    Thick Film Gravured Dye Transfer Matrix as National Geographic Tiffdruck Rotogravure

    National Geographic Magazine Press was making excellent job before they are changed from Slide Film to Digital Photography , before started to investing soy bean inks , before investing worse photographers and their worse equipment . This was may be 15 years ago , everything changed.

    Now lets bring these old days to today again.

    They were using rotogravure presses or german name tiffduck process similar to dye transfer process. Rotogravure presses were using copper plates to print the media and these copper plates were covered with different depth and different size holes.

    When they feeded with ink, shadow areas were presented with larger size and greater depth of holes with elliptical shape.This was similar to dye transfer where the shadow areas thicker at matrix.

    Rotogravure uses gelatin coated copper where gelatin acts exactly same but negative as traditional dye transfer matrix where shadow areas thinner on gelatin and acid etches the screening in to copper with thinner gelatin etches more , thicker gelatin etches less , shallower.

    I am thinking to use thick polyester film as copper plate. Acid will be injected on to polyester film with inkjet printer and rest was easy.

    Can I inkjet square or elliptical screening on to polyester ? Or must it be a 1 bit screening ? And other idea is to use palladium toner as ink at the tiffdruck process.

    Mustafa Umut Sarac

    Istanbul

  2. #2
    holmburgers's Avatar
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    Hi Umut,

    Tiffdruck and rotogravure are really fascinating processes, and the benefit of the copper plate was that it could be used to print thousands of copies without deteriorating.

    So what would be the benefit of a polyester version?

    You could essentially create the same type of printing plate with gelatin on PET and a screened negative. This could be used for bromoil/oil or dye-imbibition.

    But, ok... maybe I see your line of thinking now. You want to transfer palladium toner (for instance), which is an aqueous solution that wouldn't necessarily function like an anionic dye (dye imbibition) or a greasy ink (bromoil/oil). So in this case, it seems like you're looking for the ability to transfer something other than an anionic dye, which has a unique relationship with gelatin, or a greasy ink, which is needed for oil printing wherein a water-saturated gelatin relief repels oil (a non-polar substance).

    Now, as for etching polyester, I have no idea how to do that. Polyester film, a.k.a. PET or polyethylene-terapthalate is notoriously reistant to all kinds of nasty chemicals. So first you would have to find something that will eat away PET, and then you'll have to design an inkjet cartridge (probably out of gold!) that won't also be destroyed.

    Forget about printers; the things you want to do are better achieved through analog means...
    If you are the big tree, we are the small axe

  3. #3
    Mustafa Umut Sarac's Avatar
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    Hello Chris ,

    If I am not wrong, flat clean copper plates are expensive. And I have no idea to use of gelatin, I think it uses dicromate and It is dangerous. PET and polyester are different things as you know and polyester is weak to acids. Thats why , polyester based glass reinforced plastic boats are tends to osmosis.

    The good thing about printers , if you can select the screening technology , it gives different taste at the final end.

    I think working with gelatin is immensely old , nasty , results and densiometry is makes me itch. This process is damn simple and gives 3D relief also.

    Umut

  4. #4
    holmburgers's Avatar
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    Fair enough; but you could use diazo sensitizing which is not toxic, and if you're vegan you can use PVAc (polyvinyl acetate). But.. I digress.

    In the photo world, polyester film = PET/Estar/Melinex/Mylar

    So what can we use to etch this?

    I can't think of an easier way to make a relief image than by, generally speaking, cross-linking a colloid. Along your line of thinking, why don't we just use a high-powered laser to melt the polyester? That seems a lot easier than messing with chemicals and inkjet nozzles. Besides, any chemical that's going to destroy polyester is going to be a very nasty solvent, with terrible fumes.

    Lastly, densitometry won't be difficult since this will be a high contrast screening process.
    If you are the big tree, we are the small axe

  5. #5
    Mustafa Umut Sarac's Avatar
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    Yes , We can beam the Loch Ness Monster with laser beams but its not easy. The trick is to give screens a 3D relief and everything is inside of this calculation.

    I think less nasty acid is required than to beam Copper to Scotty

    Israel is using sun rays to concentrate and use at a surgery. And stereolithography uses mirrors to illuminate the photopolymer but its not easy and very very expensive.

    Buy an 30 dollars printer , find the acid , beam to the polyester and you are ready. Even buying simplest chemical costs more.

    Than buy 20 dollar palladium , prepare 250 cl solution , pour on the matrix , wipe with steel plate and contact print on a paper.

    Thats the most cost sensitive process. And quality approved long time ago. You can make color ones also.

    Umut

  6. #6
    holmburgers's Avatar
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    Ok, ok, I concede that lasers are gonna blow our budget.

    But gelatin and dichromate are cheap, and we don't need copper or acid then.

    If you find me a chemical that will etch polyester, I will fly my white flag!

    If you are the big tree, we are the small axe

  7. #7
    Mustafa Umut Sarac's Avatar
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    Here is the patent 3186883.

    Here is the research article :http://www.springerlink.com/content/kgwn7n442v57u30q/

    Those are the two polyester film etching technologies that I could find in 10 seconds.

    One is caustic potash , other one phenol + sulfuric acid.

    Article relates to printing technologies.

    Umut

  8. #8
    Mustafa Umut Sarac's Avatar
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    By the way , article is interesting for other way. Back to 1977 , Ukranians wrote it for to sub polyester film. May be it can be used in place of plazma.

    Umut

  9. #9
    holmburgers's Avatar
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    Wow, you're right, the article is all about subbing PET, which is what we were wondering about several weeks ago. I'm gonna post that to the film subbing thread, just for reference. Great stuff!

    *white flag*



    So what's the next step?
    If you are the big tree, we are the small axe

  10. #10
    Mustafa Umut Sarac's Avatar
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    Yes, reference is great Chris , if you would not me to find that PET Etching Process , it would be out of sight.



 

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