RAW file (NEF) color management in Photoshop

Discussion in 'Digital Photography' started by E. Hand, Oct 16, 2003.

  1. E. Hand

    E. Hand Guest

    I am new to shooting in RAW files with my digital camera. I would
    like to get ideas on how to color manage these files in Photoshop. I
    have noticed that the Nikon driver automatically tags RAW files with
    Nikon sRGB 4.0.0.3000. Here are some of the questions that I'm looking
    for answers to.

    1. Do RAW files have their own color gamut that is different from the
    one that Nikon has assigned and if so what is it?

    2. If I tell Photoshop to ignore the tagged profile what would be a
    good profile to assign to a RAW file that would allow me to have a
    wide latitude for editing my image. Please keep in mind that my
    output is usually ink-jet and sometimes traditional chemical
    processes.
     
    E. Hand, Oct 16, 2003
    #1
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  2. E. Hand

    MSD Guest

     
    MSD, Oct 16, 2003
    #2
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  3. E. Hand

    Quinn Keleq Guest

    I am also struggling to understand the color management
    issues in PS.
    1. The RAW format records image data as captured by the
    camera's CCD without further processing. This must be
    camera specific. Compression is reversible. Choose any
    color management format and save it as different files
    if you want for comparison.
    2. What profile you choose depends entirely on what you
    are going to do with a file. I think I would just choose
    PS default unless you have other specific purposes in
    mind.
    Quinn
     
    Quinn Keleq, Oct 16, 2003
    #3
  4. E. Hand

    Bill Hilton Guest

    From: (E. Hand)
    The camera has its own device-specific gamut and no doubt it's wider than sRGB,
    which is fine for the web but has the smallest gamut of the commonly used
    working spaces.
    AdobeRGB is a better choice for ink jet printing if you're starting with film
    scans or RAW files.

    Easiest way to set this up in Photoshop is Edit > Color Settings and in the top
    box for "Settings" select "U.S. Prepress Defaults". This will default to
    AdobeRGB as your working RGB space. (The default "Setting" for Photoshop is
    "Web Graphics Defaults", which uses sRGB as the working space).

    Bill
     
    Bill Hilton, Oct 17, 2003
    #4
  5. E. Hand

    Hecate Guest

    For printing, Adobe1998 converts to CMYK better than sRGB. (And your
    printer will convert internally - you don't have to do that).

    For web sites/monitor viewing then sRGB is a better colour space as it
    reflects the monitor colour space. However, because Adobe1998 copes
    with both viewing *and* printing, it's better to use that as your
    working colour space. Just remember that it has a wider gamut than
    sRGB.
     
    Hecate, Oct 17, 2003
    #5
  6. E. Hand

    Flycaster Guest

    [snip]
    Just out of curiosity, why is that? Is the gamut a better match, or does it
    have something to do with a "grey-balanced" RGB colorspace?
     
    Flycaster, Oct 17, 2003
    #6
  7. E. Hand

    MSD Guest

    i
    -----
    Not wishing to speak for Hecate
    (she certainly does that well enough for herself)
    --
    There are profiles for input and output
    these are basically "storage spaces" defining a device.
    --
    Then there are working spaces
    they are written to facilitate the "moving" / converting of files
    from one profile to another.
    --
    There is a science there - where each part does its particular task.
    Not unlike applications used for printing where you have
    vector design apps - bitmap manipulation apps - layout apps.

    The idea is to use the correct tool for the job.
    (Grey balance would be part of that equation)

    MSD
     
    MSD, Oct 17, 2003
    #7
  8. E. Hand

    E. Hand Guest

    Thank you, very helpfull.
     
    E. Hand, Oct 17, 2003
    #8
  9. E. Hand

    Flycaster Guest

    Boy, Mike, I normally follow you pretty well but you kinda lost me on this
    one. I'll re-read it in the morning!
     
    Flycaster, Oct 17, 2003
    #9
  10. E. Hand

    Quinn Keleq Guest

    This is what I just read about Photoshop CS - the new ps for mac:
    a.. Integrated digital camera raw file support - Get truer, higher quality
    output by working with the complete raw data files from most major digital
    camera models.
     
    Quinn Keleq, Oct 17, 2003
    #10
  11. E. Hand

    Flycaster Guest

    Never mind, I looked it up this morning over a cup of coffee. You threw me
    with the "storage space-working space" part - as I already knew, neither is
    a device profile, they are both working spaces, and they are both
    grey-balanced (this last part, however, I was unsure of.)

    Rather, as I suspected, the issue is *gamut.* Per Blatner/Fraser, from "RW
    PS 6", pg. 153:

    "sRGB has a serious mismatch with the gamut of offset printing. It clips
    the cyans, and those blues and greens adjacent to cyan, quite drastically.
    With a typical sheetfed printing setup, you'll never get more than 75% cyan
    ink when you convert an RGB image in sRGB to CMYK."

    Anyway, thanks. I now know something I have already read 100 times, and am
    very likely to forget again. ;)
     
    Flycaster, Oct 17, 2003
    #11
  12. E. Hand

    Hecate Guest

    As I was about to say...oh, never mind. Yes, that's the answer. If you
    use the Adobe 1998 you get less clipping as the colour space is a
    better match for CMYK. Which is what MSD said...I think ;-)
     
    Hecate, Oct 17, 2003
    #12
  13. E. Hand

    Mike Russell Guest

    [re Adobe RGB and CMYK gamuts]
    It's interesting to note that Bruce RGB, takes the opposite tack, and
    occupies a smaller gamut to better match the overall footprint of
    inkjet-based CMYK better. The object of this strategy
    is reducing the number of unprintable RGB color values, which makes sense
    for an inkjet that can accept only RGB data.

    BTW, there is an entirely different tactic to using more of the CMYK gamut:
    do your color corrections in that space, rather than correcting in RGB and
    using a profile that is based on a compromise. This is how the very best
    printed images are done.

    If you want a quick comparison of the gamuts of the various color spaces
    installed on your system, you may be interested in this downloadable "gamut
    viewer" Lab image from curvemeister. Using it, you can easily compare the
    relative footprints of profiles such as Adobe RGB, sRGB, and SWOP Coated
    CMYK:
    http://home.pacbell.net/geigy/tutorials/gamutviewer/index.htm


    Mike Russell
    http://www.curvemeister.com
    http://www.zocalo.net/~mgr
    http://geigy.2y.net
     
    Mike Russell, Oct 24, 2003
    #13
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