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Thread: Scanner as densitometer.....

  1. #21

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    Re: Scanner as densitometer.....

    Vuescan will also let you lock exposure. You could scan your wedge, record the density values of the steps you care about, lock the exposure, then scan your negative. That should make the density values it displays comparable.

  2. #22
    Kirk Gittings's Avatar
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    Re: Scanner as densitometer.....

    That seems like it might work Ed.
    Thanks,
    Kirk

    at age 73:
    "The woods are lovely, dark and deep,
    But I have promises to keep,
    And miles to go before I sleep,
    And miles to go before I sleep"

  3. #23
    Kirk Gittings's Avatar
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    Re: Scanner as densitometer.....

    FWIW, my primary seat of the pants method over the years has been a version Picker's proper proof. The key to is a contact sheet with the minimum exposure necessary to render film edge as black. From there it is easy to get a rough idead about the accuracy of your film ISO settings and highlight development with a particular film dev. combination. It actually works quite well on its own without using a densitometer-not precise but it will do. I only used this method for a couple of decades.

    I think I can do something similar by doing a raw preview in Epson 750 software-importing it to PS with no settings and then only setting the black point just high enough in levels to render the film edge as black (K value in the Info panel at 100% output). From there you can get a pretty good idea about your ISO settings and development for the highlights. This gives you some rough information quickly in the flow of things about ISO settings, shadow placement, highlight development/placement, filter factors etc. I think the step wedge idea might tighten this method up.
    Thanks,
    Kirk

    at age 73:
    "The woods are lovely, dark and deep,
    But I have promises to keep,
    And miles to go before I sleep,
    And miles to go before I sleep"

  4. #24

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    Re: Scanner as densitometer.....

    Quote Originally Posted by Kirk Gittings View Post
    FWIW, my primary seat of the pants method over the years has been a version Picker's proper proof. The key to is a contact sheet with the minimum exposure necessary to render film edge as black. From there it is easy to get a rough idead about the accuracy of your film ISO settings and highlight development with a particular film dev. combination. It actually works quite well on its own without using a densitometer-not precise but it will do. I only used this method for a couple of decades.

    I think I can do something similar by doing a raw preview in Epson 750 software-importing it to PS with no settings and then only setting the black point just high enough in levels to render the film edge as black (K value in the Info panel at 100% output). From there you can get a pretty good idea about your ISO settings and development for the highlights. This gives you some rough information quickly in the flow of things about ISO settings, shadow placement, highlight development/placement, filter factors etc. I think the step wedge idea might tighten this method up.
    Can you simply "tape" the step wedge onto the glass next to the negatives. The half-inch 21-step can usually fit for the purpose. Include the image of the step wedge on every scan. No matter what your scanner settings are (you can find mistakes this way). You will always be able to eyedropper the negative's highlight and find the matching step wedge "step" - to know the density range. Or find any density of any spot on the neg this way.

  5. #25
    bob carnie's Avatar
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    Re: Scanner as densitometer.....

    If you are using a Mac and like the L channel then use a colour meter to read all your values. I use a colour meter with my scanner to fine tune density and colour adjustments that the scanner software seems lacking in. This meter is independent to PS and your scanner software and is wonderful to work with.

    On all our computers a Digital Colour meter is set up to CieLab settings with a small apeture so you can get in and get about a three to four reading.
    I find it invaluable. I like Bills idea of including a step wedge for comparison.

    Quote Originally Posted by Bill Burk View Post
    Can you simply "tape" the step wedge onto the glass next to the negatives. The half-inch 21-step can usually fit for the purpose. Include the image of the step wedge on every scan. No matter what your scanner settings are (you can find mistakes this way). You will always be able to eyedropper the negative's highlight and find the matching step wedge "step" - to know the density range. Or find any density of any spot on the neg this way.

  6. #26
    Kirk Gittings's Avatar
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    Re: Scanner as densitometer.....

    Quote Originally Posted by Bill Burk View Post
    Can you simply "tape" the step wedge onto the glass next to the negatives. The half-inch 21-step can usually fit for the purpose. Include the image of the step wedge on every scan. No matter what your scanner settings are (you can find mistakes this way). You will always be able to eyedropper the negative's highlight and find the matching step wedge "step" - to know the density range. Or find any density of any spot on the neg this way.
    That should work IMO.
    Thanks,
    Kirk

    at age 73:
    "The woods are lovely, dark and deep,
    But I have promises to keep,
    And miles to go before I sleep,
    And miles to go before I sleep"

  7. #27
    Tin Can's Avatar
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    Re: Scanner as densitometer.....

    Old thread.

    Is there any newer thinking on this scenario?
    Tin Can

  8. #28
    Andy Eads
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    Re: Scanner as densitometer.....

    In the appendix of my book posted here: http://www.largeformatphotography.in...cles/VIDEC.pdf
    is a means of using a spot meter as a densitometer. I've had pretty good results with this method though it is tedious. Scanning has the advantage of highly localized measurement. In a pinch however...

  9. #29
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    Re: Scanner as densitometer.....

    Hi,

    Can I offer my test results for discussion ? I personally don't see how others cant use these results with a fair amount of accuracy.

    Cheers,

    Steve

    Scanner results from Stouffer tablet.pdf

  10. #30
    Tin Can's Avatar
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    Re: Scanner as densitometer.....

    Quote Originally Posted by swmcl View Post
    Hi,

    Can I offer my test results for discussion ? I personally don't see how others cant use these results with a fair amount of accuracy.

    Cheers,

    Steve

    Scanner results from Stouffer tablet.pdf
    Thanks! That is handy and useful.

    As a hobbyist, I am not concerned with absolute scientific and traceable results but more a personal working index and method, not unlike finding personal EI or chemistry preferences.

    Perhaps others have different results?
    Tin Can

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