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Thread: Proper use of a Color Densitometer for B&W Negatives

  1. #1

    Proper use of a Color Densitometer for B&W Negatives

    Greetings,

    When using a color transmission densitometer that has red, yellow, blue and whit e channels, what is the correct way to read density on B&W negatives? I've hear d that Pyro negs should be read on the blue channel - why? What difference does it make to read between one of the color channels or the white light channel? Thanks!

    Regards,

  2. #2

    Join Date
    Oct 1999
    Posts
    34

    Proper use of a Color Densitometer for B&W Negatives

    Pete, where did you get those colors from? Is this a Macbeth unit and you're stating the color of the dots on the turret or something? Those units would typically have cyan, magenta and yellow dots to signify the color of the dye you would be reading. If you didn't know this, you might figure they are blue, red and yellow respectively.

    The dot that is NOT colored would typically be what they call a "visual response" mode; it gives a broad spectral coverage and is what should normally be used for B&W negs.

    When you use one of the colored responses, they are typically very narrow spectral bands, depending on the "status" of the response. Status M is for color negatives, Status A is for slides or reflection prints. However, since silver (in B&W) is not very spectrally selective, you should get very nearly the same density readings with any of the response functions.

  3. #3

    Proper use of a Color Densitometer for B&W Negatives

    Thanks Bill. Yes, it is an older Macbeth densitometer and the colored dots could very well be cyan, magenta and yellow. They're faded now and appear red, blue, etc.

    Regards,

  4. #4

    Join Date
    Nov 1998
    Posts
    339

    Proper use of a Color Densitometer for B&W Negatives

    Use the plain or visual mode for most negs. If you're reading negs developed on pyro or that otherwise have a strong yellowish stain you'll notice a significant difference between the visual and blue/cyan filter readings; actual printing de nsity on VC paper will fall in between.

  5. #5

    Join Date
    Dec 1997
    Location
    Baraboo, Wisconsin
    Posts
    7,695

    Proper use of a Color Densitometer for B&W Negatives

    My Macbeth densitometer has red, green, and blue looking dots on the left and right side of the knob that selects the channel. At the bottom, in between these two rows of dots, there is an orange looking dot. On mine (which obviously may be a different model from yours) the instructions say to use the orange dot for black and white.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  6. #6
    Kevin Kolosky
    Join Date
    Jun 1999
    Posts
    801

    Proper use of a Color Densitometer for B&W Negatives

    make sure that you calibrate it first with a known density calibration negative. I purchased mine as a step wedge from a company called Stouffer. There should be a button on the back of your unit that will allow you to calibrate to the known density wedge. Kevin

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