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  1. #91
    Stephen Frizza's Avatar
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    if its of any interest i have been playing around with screens and films and so far this is as good as I have been able to come up with. do you find too that your screen causes a degradation in fine detail?
    Attached Thumbnails Attached Thumbnails B&WposviaRGBscreen.jpg  
    "Its my profession to hijack time" ~ Stephen Frizza.

  2. #92
    glbeas's Avatar
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    Quote Originally Posted by holmburgers View Post
    Ok, so I got back my latest screen-plates. These I made by photographing a flat-screen CPU monitor. Both good news and bad.

    Since my earlier tests turned out blue, I made a custom color that was a light yellow. What I got back were distinctly green slides. At first I couldn't wrap my head around it; I thought maybe it was a processing error, I thought maybe the film was too old, maybe the heat encountered in mail-order shifted the color.... etc.

    HOWEVER, the lightbulb over my head lit up and I realized that this color shift is due to the fluorescent illumination used in flat-screen monitors. Duh!

    The good news is that under the loupe I can see definition to the RGB elements, however I can't make out the colors. But the lens can render this fine detail and the resolution promises to be excellent with CPU monitors.

    Meanwhile I've taken a picture with my first bluish screen-plate under tungsten light (to hopefully balance it out). That film will be going to dr5 soon.

    So any suggestions on dialing in this color? I've decided that I can't continue using/wasting 4x5" film until I have the right color balance, so I think I'll be running a roll of 35mm with many different source colors to see what comes out the most neutral on the slides. But since I'm dealing with fluorescent illumination, aren't I kind of shooting in the dark? If I add magenta to my source, can I expect that to eliminate the green, or is it going to be more complicated than that?
    If you wanted to spend the money there's a new breed of LCD moniter out that uses white LEDs as a light source, and are brighter with a higher contrast ratio.
    Either way you should be able to color balance the monitor screen to any color you want in spite of the light source.
    Gary Beasley

  3. #93
    holmburgers's Avatar
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    Stephen, that result is stunning. What are you using for the screen? Is that 4x5"? Definitely of interest to me and others I'm sure! I'd love to hear your method.

    As for fine-detail, I can't speak authoritatively as I've still only got one example under my belt. It does stand to reason that there will be a loss of fine detail, due to the fact that a pure green object (for instance) would only be using 1/3 or less of the screen in that area.

    glbeas, that monitor sounds awesome, but I'm in no position to buy one at the moment. At some point I am going to shoot a roll of 36 with different filtration to see what comes out the most grey, and then use the best for my 4x5" screens.

  4. #94
    Athiril's Avatar
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    I'm going to try dye some starch and mix it into a gelatin emulsion and paint it on top of some foma, I dont think it'll hold during processing, but I can re-apply a screen after scanning (or painstakingly on some RA-4 when I get an enlarger).

  5. #95
    holmburgers's Avatar
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    How do you propose to re-apply an identical, stochastic, screen? I think that would next to impossible, as each screen element has to be in exactly the same place during exposure and viewing.

  6. #96

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    The coloured starch grains in the emulsion worked as screen in the original autochromes for both exposure and viewing, didn't they?
    No need then for external masks.

  7. #97
    holmburgers's Avatar
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    Yes, there'd be no other way to do it with a stochastic screen like that.

  8. #98

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    So problem solved by not being a problem.

  9. #99
    holmburgers's Avatar
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    I'm confused... what problem, whose problem?

    This is becoming a problem....

    Problem

  10. #100
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    You cannot use a "screen" process for color photography unless you view using the identical same screen in register with the B&W screen produced positive. It will not work any other way! You cannot remove the screen and generate a new one as the new one, using the method proposed, will not duplicate the original.

    PE



 

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