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  1. #91
    Mustafa Umut Sarac's Avatar
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    Ian ,

    Did you succeed to make an paper equivalent of Brovira 40 years ago ? Could you please share know how with us ? What is the tricks of your Brovira formula post two years ago ? What about gelatin , how did you do that ? If you post them , I will send you Gustav Mahler Complete CD set as I am listening now where 1000 musicians play together !!

    You dont need to hurry , few posts a week complete the task until the summer I hope.

    Thank you ,

    Umut

  2. #92
    Mustafa Umut Sarac's Avatar
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    And an bottle of Chivas Regal

  3. #93
    Ian Grant's Avatar
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    Umut, I wasn't trying to make a paper emulsion like Brovira, however I did trial Ilfospeed Grade 3 emulsion after I was approached by Ilford, they were interested in supplying me with emulsion, and my main emulsion had similar speed & contrast. So I guess making a Brovira type emulsion wouldn't have been difficult, the importance of things like the FIAT report Agfa formulae is more to do with how different companies control variables to give different contrast grades and emulsion speeds particularly varying the digestion & ripening times & temperatures.

    So even a simple emulsion formula can be dramatically improved by finding the right time/temperature combinations for a particular gelatin.

    Ian

  4. #94
    Photo Engineer's Avatar
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    Umut;

    Using inactive gelatin, I found that a Brovira type emulsion was properly sensitized by using about 100 mg of Sodium Thiosulfate Pentahydrate per mole of Silver for 1 hour at 60 degrees C. This will give a speed close to Ilford MGIV paper. The addition of Rhodium Chloride at 10^-6 moles per mole of Silver will give an additional contrast boost. It should be added just prior to the addition of Silver Nitrate during the initial precipitation.

    The Sulfur treatment is applied after the wash. Variations in this treatment will cause variations in contrast from low to high.

    PE

  5. #95
    Mustafa Umut Sarac's Avatar
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    Ron ,

    You deserved Turkish Coffee with instructions. Its up to you to find a Arap Half Nude Cariye to cook for you. Send me your address and coffee is yours

  6. #96
    Photo Engineer's Avatar
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    No, that was a gift to you and other APUG members with no return expected!

    An added side comment. Do not use gold sensitization with any paper print material, as the toe and overall contrast will be very low.

    PE

  7. #97
    Mustafa Umut Sarac's Avatar
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    Thank you for your 16000 gifts as there are some post bombers out there. Even more than a Santa did.

  8. #98
    holmburgers's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Some quotes from Wall:...
    Neither of these is correct! I hope that puts Wall in perspective!

    In addition, the back of the book is completed by several ads for photographic gelatins.
    Just as aside (I have no agenda to disregard Wall or anything), but reading F.E. Ive's "Autobiography of An Amateur Inventor", which is a fascinating and rare book, he mentions that he and Wall basically hated one another. They were fierce competitors and Wall intentionally omitted Ive's work in his books and did not attempt in the least to give him his credit.

    I've not read any of Wall's books other than one of his dictionaries, and I recall that the F.E. Ives entry was rather short. Friedman on the other hand gives him his due, and indeed he had lots of brilliant ideas. He pioneered three-color photography with his Kromskop and also full color printmaking with his work on half-tone screens, etc. One cool dude!

    If you can get the book, it's worth a read for sure. Just don't interlibrary loan it from my library and steal it. It seems to be very rare, and the book is full of interesting appendixes and taped-in additions like, "The Author would like to have a complete list of persons who own this book"[sic].

  9. #99
    Photo Engineer's Avatar
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    Wall even omitted details of his own work, I suspect in order that it be difficult for others to reproduce it and so he would stay in the forefront of this type of work.

    I have located a reference here: http://en.wikipedia.org/wiki/Levi_Hill that might be of interest to some of you.

    This is supposed to be the first true full color photographic system and was based on daguerreotype imaging.

    PE

  10. #100
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    Ahh, yeah, the hillotype. I read something about this a while back, I think he basically went crazy and died because of the chemicals he was working with. Or am I just spreading rumours?

    Ive's pioneered three color, leading our modern system in favor of the search for direct color like Hill & Lippmann.

    Are you familiar with Wood's diffaction color? It's a completely different way of producing color that sounds really interesting and fairly easy to do (even relatively speaking... pretty easy). He made diffraction gratings in dichromated gelatin of the 3 color records thru 3 ruled line screens; each ruled line screen was different and chosen so that from a given viewing location, the proper primary would be diffracted. Combine those 3 clear gelatin matrices and viewed from the right position it's a full color image.

    update: Frederic Ives actually invented the half-tone process, and his son Herbert E. Ives transmitted the first television signal, pioneered an early color TV and also tried to disprove Einstein's Theory of Relativity. The latter of which we can just forget for his legacy's sake.
    Last edited by holmburgers; 12-13-2010 at 03:30 PM. Click to view previous post history.



 

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