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8 bits and 16 bits questions (Photoshop)

Discussion in 'Image Processing' started by rossi46, Dec 4, 2012.

  1. rossi46

    rossi46 Mu-43 Regular

    141
    Mar 1, 2012
    Hi All,

    I am fully aware of the advantages of 16 bit mode in RAW files.

    My question is this -
    I was using 8 bit mode to perform all my editing (curve layers, level layers, etc).

    If during halfway processing all the editing in 8 bit mode, I decided to switch to 16 bit mode -
    What happens?
    All my adjustments will not be affected, and has more data and more smooth transitions?
     
  2. clockwise

    clockwise Mu-43 Regular

    38
    Apr 23, 2012
    New York, NY
    Brian R
    If your original image wasn't opened as a 16-bit file, you've essentially thrown away much of the pixel data that your camera initially recorded. Changing back to 16-bit after you've processed the Raw file won't bring that information back. If you want to squeeze out every last bit of your camera's performance you'll need to go back to the original file and open it as a 16-bit image.

    I've never tried switching from 8- to 16-bit after opening a file, but I'd be surprised if it affected your prior adjustments.
     
    • Like Like x 1
  3. flash

    flash Mu-43 Hall of Famer

    Apr 29, 2010
    1 hour from Sydney Australia.
    Gordon
    Like Clockwise said. Once the data's gone you can't get it back. Changing up to 16 bits from 8 bit will just fill out the extra bits with useless "0"'s so you're just adding to the file size and acheiving nothing else. If you've started in 8 bit just leave it there.

    However, although working in 16 bit is ideal, often the differences are subtle, in the final product so don't stress too much about it. It's likely reworking the file will bring only small improvements that may not even be noticable. If you do start to see posterisation in colour bands (say large sections of sky) of sudden and severe clipping then maybe go back and redo the file. Otherwise don't worry about it.

    Gordon
     
    • Like Like x 1
  4. rossi46

    rossi46 Mu-43 Regular

    141
    Mar 1, 2012
    How do we open up the file in 16bits? During the Acrobat Raw Conversion stage we have to perform the settings? Or before we open up the DNG, we have to use photoshop to switch it to 16 bit image mode?
     
  5. clockwise

    clockwise Mu-43 Regular

    38
    Apr 23, 2012
    New York, NY
    Brian R
    It has to be done when you have the Raw file open in ACR, before you process the file and open it in Photoshop or Lightroom. Click on the blue line of text under the main image window in ACR, and a dialog will pop up where you can choose your processing settings. At least that's how it's done in ACR 6, not sure about the new version but I suspect it's a similar process.
     
  6. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
    Export your file from your RAW converted as a 16 bit TIFF, for example.