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  1. #11
    Lee L's Avatar
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    Quote Originally Posted by srs5694
    I've never used a densitometer before, but I've been getting curious about densitometer measurements as a means of calibrating film speed and development times. I do own a scanner (a Minolta DiMAGE Scan Elite 5400), though, and was wondering if it's possible to get densitometer-style values out of it for this purpose. Any suggestions or pointers?
    See Helen B's first post to this thread for a basic outline of how it would be done. I haven't done this myself.

    The step wedge she's referring to would be something like a Stouffer multiple step wedge (probably a 31 step version preferred?) in whatever format you're going to scan. I think they make a version with 11 steps at one stop intervals specifically for scanners, but finer steps allow finer tuning of the process.

    If you get the same size as the film you're shooting, you could use it in both the scanner and the enlarger for a fixed transmission standard that ties the two processes closely together for calibration and previewing as accurately as you can from a scan.

    Lee

    http://www.stouffer.net/Stoufferhome1.htm

  2. #12
    hortense's Avatar
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    Helen - I'm sure your suggestions are valid. To me however, this seem too complicated (at least for my generation). How about recommending a simpler method?
    [FONT=Times New Roman]MAC[/FONT]

  3. #13
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    I was hoping for something that would get me close to print quality without too much investment in time or money.

    I'm using an Epson Perfection 1660, which is already a couple of years old. I can't justify the expense of high end, nor am I talented enough to write software. My most basic aim is to find a way, through my present set up, to help evaluate my negatives and see where I need to go in the printing process...

    If I had the time, Helen's suggestion really looks interesting. But alas, I'm lucky if I can into the darkroom once per month; and that includes developing exposed film.

  4. #14
    MattKing's Avatar
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    Quote Originally Posted by Helen B
    Therefore what you want is not the best scan you can get, but a scan that is representative of how a piece of paper will respond, or preferably, will allow the paper response to be mimicked in PS.

    I'd do it by producing a standardised file from the scanner - ie one in which a certain transmission density will always correspond to a certain greyscale value (I'm using B&W for simplicity of description, the same system would work for colour). I'd achieve that by using a step wedge with scanning software like Vuescan ($50) that allows you to fix the scanner 'exposure'. Then, knowing the paper's response curve to that step-wedge for each contrast grade, I'd write a little PS filter that applied the paper curve to the film scan file and allowed the choice of paper grade and exposure - ie the ability to select the portion of the film's response curve that would be translated to the paper. Easier to explain with a few diagrams than to put into words, especially as this should be explained at greater length than I've done quickly here. If I'm on the right lines let me know and I'll explain further.

    Best,
    Helen
    Helen, this looks like a great idea for those of us whose access to darkroom time is limited. Any further explanation would be appreciated.

    Quote Originally Posted by Lee L
    See Helen B's first post to this thread for a basic outline of how it would be done. I haven't done this myself.

    The step wedge she's referring to would be something like a Stouffer multiple step wedge (probably a 31 step version preferred?) in whatever format you're going to scan. I think they make a version with 11 steps at one stop intervals specifically for scanners, but finer steps allow finer tuning of the process.

    If you get the same size as the film you're shooting, you could use it in both the scanner and the enlarger for a fixed transmission standard that ties the two processes closely together for calibration and previewing as accurately as you can from a scan.

    Lee

    http://www.stouffer.net/Stoufferhome1.htm
    Lee, thanks for the further explanation, and the Stouffer link. I could see that it would also be useful to combine this with the use of an analyzer or enlarging meter, so as to improve the results on that "1st test print".

    Thanks again, to both of you,
    Matt
    Last edited by MattKing; 08-11-2005 at 09:31 PM. Click to view previous post history. Reason: further thoughts, and reading more carefully further posts

  5. #15
    Lee L's Avatar
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    Joe,

    I understand about time constraints, as I have many of my own. But if you want to calibrate, you'll still need to do the work. Vuescan is $50 for the standard version as Helen mentioned, and it's great software. It does support your 1660, so you don't need to do any coding.
    If the step wedge and Vuescan are too costly and time consuming, you might try making up your own transmission step wedges from negatives from photos of paint chips, the sample cards of a neutral gray scale at a hardware store. If you have a spotmeter or can get in close with no shadows from a reflectance meter, you could get a decent reading of the original scale to use for calibration. Other people have painted a flat board and lit it from one end, marking it with indicators for each stop of light falloff along the length of the board. (That might be a little hard to read densities from on a 35mm frame, but in a print, it's useful.)
    I've found that reading densities of full frame single tone shots on 35mm can be done reasonably well with a reflectance meter, both with a spotmeter and with a Gossen LunaPro and the enlarging meter attachment. The same could probably be done relatively well with any smaller aperture reflectance meter and a diffuse light source. If you only get 1/3 stop resolution, you're still way ahead of not knowing anything.
    PM me if you have questions about how to do this without a scanner.

    Lee

  6. #16
    joeyk49's Avatar
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    Thanks, Lee:

    You've got me scratching my chin and thinking, "...could make this work, yet..."

    I'm glad I posted the question.

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