Silly idea for calibrating printers...

Discussion in 'Beyond the Basics' started by freixas, Aug 14, 2018.

  1. freixas

    freixas TPF Noob!

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    Let's say you have a tool to calibrate your camera under some specific, reproducible lighting conditions, something like xRite's ColorChecker Passport.
    1. Take a photo of the CC Passport under the reproducible lighting.
    2. Run the CC Passport tool to create a color profile for the camera. Viewed on a calibrated monitor, the photo of the CC Passport pattern should match the CC Passport (within the limits of the monitor's color space).
    3. Print the image on your printer without using a printer color profile (the color profile produced in step 2 should be embedded in the image).
    4. Take the resulting print, place it under the lighting in step 2 and take a photo of it.
    5. The tricky part is that you need to run the CC Passport tool on this photo after the camera color profile is applied. If the tool ignores the previously created camera profile, it will correct produce a screwy color profile for the camera, rather than one for the printer.
    6. Print the image in step 3 using the color profile produced in step 5.
    Will the final print now match the CC Passport pattern (within the limits of the printer's color space)? Have I just calibrated my printer without needing a calibrator such as the ColorMunki Photo? It seems unlikely it would be this easy.

    The CC Passport requires a DNG. DNGs (like other RAW files) don't have color profiles—you are working with the raw sensor data. For my method to work, you have to correct for the camera sensors' linearity problems—you need a "raw" file that the CC Passport would think needed no adjustment at all if the photo was of the CC Passport. But if the photo were of a printer's version of the CC Passport, then it would generate a color profile that would correct just printer.

    Does anyone know of any clever ways of producing a "color-corrected" DNG? Does anyone have any other clever work-arounds to spending $500 for a Color Munki Photo?

    My use case is hobbyist, not professional. It would be nice to be able to get color profiles for various ink, paper, printer combinations without yet another major investment in gear.


     
  2. BrentC

    BrentC Been spending a lot of time on here!

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    Just pay $40 for an online provider to create the profiles for you. A lot cheaper than buying a calibrator and will save you headaches.
     
  3. freixas

    freixas TPF Noob!

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    Thanks. I'm aware of the online profile providers.

    One other problem that occurred to me with my approach. Printer calibration is probably performed relative to some standard light source, so the lighting in steps 2 and 4 might need to be carefully calibrated. On the other hand, I had a vision of creating a color profile for ink/paper/printer and lighting, so that if I planned to put a photo in a particular spot, I might be able to print it so it looks optimal under that specific lighting condition.

    I know there are some tricks used for exhibition photos where they are printed darker but displayed under bright lights. As I understand it, this makes the image seem more intense than a lighter image in less light, so there must be some way to determine how to print a photo for varying light levels.
     

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