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Thread: Too good to be true?

  1. #1

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    Too good to be true?

    A friend shared this with me: http://jakubkotrc.com/paper-exposer

    I won't dwell on why I think this is impractical for all but the most casual darkroom use. But what I do think is interesting is the use of a tablet as what amounts to an additive multi contrast enlarger light source. IF the light is even enough across the screen and IF the color output (to adjust contrast) is accurate and repeatable. Essentially just lay this on top of your existing condensers (granted, need to address light leakage). With all the effort some have put into building LED light sources, this seems too good to be true.

    The app has been out for almost a year but I could not find any mention of it here. Or on apug/photrio.

    Thoughts?

  2. #2

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    Re: Too good to be true?

    Good question. I wouldn’t have thought you could get enough light, but what do I know.

    Coincidentally, I’ve been wondering about a potentially even more attractive alternative in electroluminescent panels, since IC-racer posted about the inner workings of an X-Rite sensitometer which employed one. With an ELP, theoretically one could do away entirely with everything above the negative stage since the ELP itself (which does indeed put out uniform light) could simply be the top glass of a negative carrier.

  3. #3
    Tin Can's Avatar
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    Re: Too good to be true?

    Bought it

    will try next week

    grinding gg today
    Tin Can

  4. #4
    Eric Woodbury
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    Re: Too good to be true?

    This is only my two bits...

    It is unlikely any tablet would emit enough violet light to give the highest of contrast possible with VC paper. I'm using an LED light source made with "green" and "royal blue" LEDs. Royal blue is the key here and what gives grades near and above #5. You wouldn't want 'royal blue' on a tablet. Working with mine in the open (during testing) mandated the use of special flip-down arc glasses or I developed immediate headaches from the near UV emissions. Also, not sure about the overall brightness. An LED source is blinding in the open, but then again, it is more light that necessary by a couple of stops.

    -e-

  5. #5
    (Shrek)
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    Re: Too good to be true?

    I wonder if you could do contact printing, assuming your tablet is large enough? Photograph the negative, work out an alignment system, adjust contrast as desired, then it would be powerful enough to do a contact print and probably could time the exposure as well.

  6. #6
    ic-racer's Avatar
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    Re: Too good to be true?

    People have been putting iDevices in enlargers for years. I'm not sure this is better to us a camera in stead of an enlarger. I may be missing something of what the device does. Either way, where would one put the negative?

    Click image for larger version. 

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  7. #7

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    Re: Too good to be true?

    Quote Originally Posted by Jody_S View Post
    I wonder if you could do contact printing, assuming your tablet is large enough? Photograph the negative, work out an alignment system, adjust contrast as desired, then it would be powerful enough to do a contact print and probably could time the exposure as well.
    I hadn't thought about contact printing. But for LF, I'm thinking just use the tablet as a light source on top of the negative or a few inches above. The benefit is to allow the use of multi contrast paper.

  8. #8

    Re: Too good to be true?

    Quote Originally Posted by HMG View Post
    The benefit is to allow the use of multi contrast paper.
    You can use filters below the lens. I don't see benefit at all.

  9. #9

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    Re: Too good to be true?

    Quote Originally Posted by ic-racer View Post
    People have been putting iDevices in enlargers for years. I'm not sure this is better to us a camera in stead of an enlarger. I may be missing something of what the device does. Either way, where would one put the negative?

    Click image for larger version. 

Name:	iPhone-iPad Enlarger.jpg 
Views:	47 
Size:	40.2 KB 
ID:	211354
    I don't think the developer intended this as a light source for an enlarger. If you look at his videos, it''s intended as a device to effectively turn a camera into an enlarger. He discusses how to address the negative. As I mentioned in my post, I see drawbacks in doing that. My interest is the concept of a tablet (or other inexpensive lcd screen) as a tunable light source for an enlarger. If people have been doing that for years, then I missed the discussion.

  10. #10
    Tin Can's Avatar
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    Re: Too good to be true?

    Yes, I have been testing and using LED lamps after I got my 10 X 10 FOTAR without a head, about 7 years past

    I posted my progress in LFPF DIY, at that time, I would have to search for it also

    and as is usual here, I got a lot of ridicule from the usual suspects

    I also use cheap LED tracing panels for showing off LF slides and internegs aka positives

    sharpshooters should now load up



    Quote Originally Posted by HMG View Post
    I don't think the developer intended this as a light source for an enlarger. If you look at his videos, it''s intended as a device to effectively turn a camera into an enlarger. He discusses how to address the negative. As I mentioned in my post, I see drawbacks in doing that. My interest is the concept of a tablet (or other inexpensive lcd screen) as a tunable light source for an enlarger. If people have been doing that for years, then I missed the discussion.
    Tin Can

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