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  1. #61
    Mustafa Umut Sarac's Avatar
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    Dear Charles , You did a very good job with obtaing this book , I did not see more than 30 dollars in this 10 year time and it is only a dream to buy this book.
    Happily I can say , You can translate the book easily with google translate.
    Only you have to do is to go to computer seller and ask a cheap desktop scanner with a good OCR optical character recognition software.
    This OCR function scan the pages and recognise the letters in to a text file . Than copy and past this text file to google translate page , select french to english and you got the translation.
    my e mail is around my profil page

  2. #62
    Athiril's Avatar
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    Quote Originally Posted by holmburgers View Post
    I had posted this idea on an older thread about Autochromes, but a friendly member directed me to this more recent thread.

    I have an idea that I'd really like some feedback on... I've concocted a method to (fairly) easily make a modern autochrome-esque, additive color photograph.

    My method would eliminate the need to devise a complicated and archaic potato-starch reseau. However, I'm sure a lot of you autochromistes' main interest lies in creating this reseau the old fashioned way, so my method might not interest you. But for those who would just like to have a unique color photograph using additive color, this might excite you as it has me.

    So, to produce a reseau by the simplest means possible, just take a picture of a white TV screen with slide film. That's it! You've got a RGB screen w/ built in lampblack, and the ability to tweak the balance by affecting tint, contrast, brightness, etc, using nothing more than the controls on your old CRT television. It would be interesting to find the optimum magnification, the optimum exposure, and so forth, but it's something that anybody could do. You just send it away for processing like normal.

    So now you've got a RGB screen. Next, just *simply* attach some equally sized black and white film to the reseau, expose, reverse process, and boom, you've got a modern autochrome.

    *Simply* though, I think not. The trick is in this part, and it's where my knowledge and experience breaks down. But basically, you'd need to adhere the reseau and b&w film together so that you could process the b&w & not harm the slide film.

    To make the b&w emulsion accessible and w/o the need to de-register the sheets, I'm thinking to soak off the anti-halation layer and epoxy it to the slide reseau with the emulsion facing towards the open, not sandwiched inside where no chemicals could penetrate. So you'd be exposing through the reseau and base of the film.

    I'm guessing that processing of the b&w would seriously harm the slide film if not protected (tell me if I'm wrong). So you'd have to coat the slide reseau with a clear epoxy, coat the edges to make sure no chemicals got inbetween the sheets, and then carryout the reversal processing.

    Now.... I don't know the first thing about (a) removing the AH backing, (b) appropriate adhesives/epoxies, or (c) reversal processing. I just know that these things are possible, and I'd love to hear what people have to say regarding the feasibility of all this.

    Thanks!

    Chris Holmquist
    holmburgers
    Thats not a bad idea, photographing a high resolution CRT or LCD monitor would be better, you would have a higher resolution filter, TV resolution is very low.

    Printing onto overhead transparency paper/film from an inkjet would be another way.

    Anyway I thought I'd throw in my 2 cents that when I've been drying film and two wet pieces of C-41 have stuck to something or to glass and I've pulled them apart days later much of the layers go with it and rip off :P

    So you might simply be able stick the wet processed film onto a b&w piece and let it dry.

  3. #63
    holmburgers's Avatar
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    Hey, thanks for the post. It's funny, as today I'm researching about reversal processing & preparing to buy the chemicals to try this out. Perhaps there's just something in the air today that says... *autochrome*

    Letting the two films stick together like you mention is not a bad idea at all, especially for the final mounting/display step.

    However, I have since revised my method outlined above with a significantly easier approach, assisted by a fellow APUGer who made some very helpful suggestions.

    Namely, pin registration. This would eliminate the need to remove the AH backing as well as worrying about the b&w processing having any effect on the slide-reseau.

    I still haven't taken the time to determine appropriate magnifications while photographing the TV screen, but here are some figures...

    The starch grains of autochromes are said to be from 5-10 micrometers in size (.005-.01 mm) and a typical 24" CRT TV has pixels approximately (grossly approximate) 200 micrometers or .2 mms in size. So basically, I need about a 1:20 magnification, or is it 20:1? Regardless, that's easy math if I had the time & formulas in front of me, I digress. I'll be using a 180mm lens.

    After I've gotten the slide-reseau processed (send away to a lab) I'm going to use a simple office hole-punch to "pin" register them. Once they're registered, tape them together securely and hopefully this sandwich will be thin enough to fit in a typical 4x5 film holder.

    Figuring exposure should be easy... eventually I'll find a suitable ISO for the reversal processing & the filter-factor of the reseau can be determined simply by metering thru it. Likewise, changes in the original TV source will be important to standardize. Messing around with 'hue', 'tint', 'picture' and all that jazz found on some TV's could be very interesting and lead to a lot of flexibility, like producing a tungsten balanced reseau for instance, or creating a warmer/cooler reseau, etc.

    Thanks for the bump and I hope to have results sometime (relatively) soon.
    Last edited by holmburgers; 05-26-2010 at 02:55 PM. Click to view previous post history.

  4. #64
    Photo Engineer's Avatar
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    Using a resau technically puts you into the realm of Dufay Color, as that is how it was done.

    And, to get a good resau, it is simple to print one onto a sheet of clear inkjet support using an inkjet printer with clear inks. I have seen a good transparency made by Mark Osterman at George Eastman House several years ago. He registered the resau with the film during exposure and then re-registered it again after processing. There was a tiny bit of color fringing IIRC due to expansion and contraction of the support. Estar would help.

    PE

  5. #65
    holmburgers's Avatar
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    Yes, that's a great point. I guess it is basically a dufaycolor, perhaps more so than an autochrome. And agreed that using an inkjet would be suitable, though I'd like to think that the slide film would produce purer colors & would be easier for me, who doesn't own a good inkjet printer.

    However, the inkjet will be what I use in 50 years when slide film is all but discontinued.... can we even hope for 50 years??

    thnx!

  6. #66
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    Well, this is the point then. Dufay is easy to reproduce and has been by many workers, but Autochrome is hard! It is then your choice as to which you want. But lets be sure that whichever way you go, lets use the right terms for it. I'm sure that either will turn out fine once one achieves the proper film and "filter package". I use this as a generic term for either method.

    PE

  7. #67
    holmburgers's Avatar
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    Since I've got your attention, could you tell me where the photo-emulsion was in relationship to the reseau and glass in an original autochrome plate? This has always puzzled me, as it seems like it would have to be sandwiched, thus making processing difficult.

  8. #68
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    Easy to do. Sheet of film/resau/ ! This sandwich was taped together in register using register pins to establish register through punch holes. Then these two sheets were placed in a holder and exposed with the resau towards the light source. The resau was smaller than the film to allow the film to fit in the holder.

    After exposure, the two were separated and the film was processed. They were then remounted in register for projection. When I saw it, Mark had them as 2 sheets and he projected the B&W slide first then moved the resau over the film and you could see colors rainbow across subjects.

    There is another method using 35mm where the resau is somehow mounted in front of the film but behind the focal plane shutter. In my opinion, this method would change the focal plane of the film.. The method I saw used sheet film which I believe was 4x5 or smaller.

    I gave this some thought and a simple printing program in visual BASIC should accomplish making a fine resau. Marks was rather coarse.

    PE

  9. #69
    Mustafa Umut Sarac's Avatar
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    Ron ,
    I am thinking inkjet RGB and more inks - like rose bengal may be - to the paper.
    Does its result be different than autochrome ?

    Umut

    Istanbul

  10. #70
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    Well, your resau would be R/G/B in a defined pattern, and inkjet R/G/B is quite good for an additive system so it should work.

    Technically, it is not the random starch grains of Autochrome with that hue, it is just about exactly like Dufay. So, they will look subtly different.

    That is about all I can say from a professional POV as a Photo System Design Engineer.

    PE

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