30D -- Disappointing?

Discussion in 'Digital Photography' started by Bill Hilton, Feb 21, 2006.

  1. I'm a person who has dealt with photography for it a while. About 44
    yrs. now. I have been troubled since digital started that it captures in
    RGB.
    The film industry has used CMYK for all of its color and as far as I know
    all processes and printers still are primary CMYK. Is there some technical
    reason why digitals camera could not capture images in CMYK? RGB is not a
    new thing to me. I worked in television before I retired. I started when
    TV was mostly B&W and can still remember all the problems I encountered
    when my company switched over to color. RGB just could not at that time
    capture colors and display them as a correct color. The hardest colors to
    work with were colors that contained yellow. My biggest client use orange in
    their logo and we had a fit making it look correct on a TV monitor. I would
    get paint color samples and would finally find a color that
    When viewed on TV looked almost like the real logo color. WE found that a
    deep red orange would look close to a true orange when showed on a monitor.
    Digital are just a modification on a TV camera. I still cannot get accurate
    colors when I use my digital. I only shoot B&W with mine and still use film
    when I desire color. I've never seen anything that will approach Chromes in
    color quality. I worked in a photo lab until I retired a year ago. I don't
    ever remember seeing a digital image that was correct and everyone always
    wanted us to correct then out before printing. Even pros who brought in
    Photo Shopped images on CD were not happy how their images came out. They
    didn't understand while it might look great on their computer with an RGB
    Monitor it didn't look the same on a CMYK enlargement. While working at the
    lab I noticed that film when scanned on to a CD was so much easier to
    get a color corrected print. I use digital images all the time but shoot
    on film and just have it scanned to a CD and not printed into proofs. I was
    doing weddings until I quit and was one of a few photographers who still
    delivered a set of color proof to my clients. I found I could take an
    image correct some thing in it and it would match in with the existing
    set of prints. Try it sometime. I think most photographers have have gotten
    cheap and don't want to spend any extra money on their jobs and it shows.
    I seen so many weddings photos that are terrible and I would never deliver
    an Image especially, a wedding photo, that looked that bad.
    I know the photo business has become hard over the last few years and I
    also blame digital for that. People now can buy a digital for under a
    thousand and in a couple of weeks decide they are now a pro and go into
    the business. I look at the photographer's adds in the phone book when the
    new books come out this year they were 31 more photographers than last
    Year in my area. What's sad is a lot of real fine photographers that been in
    the business for a while are no longer there because they can't operated a
    real studio with the overhead and compete with someone working from a home
    with a real full time job and almost no overhead. they will do an eight
    hour wedding for $400 and deliver a thousand or more images to the client.
    Back to the subject. For you technical folks that know a lot more do than
    I do about digital why did digital came out in RGB than CMYK. For you folks
    that
    don't know what CMYK means it Cyan(blue), Magenta (a red), Yellow and the K
    stands for true black. That's why Digital prints always have a slight color
    tint when you do B&W Thank for your time................
    Marshall Thurman
     
    Marshall Thurman, Jul 11, 2006
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  2. Bill Hilton

    Scott W Guest

    First off you have to understand that there is a difference between
    capturing an image and displaying it. The eye sees in RGB so if you
    want to capture an image as it is seen this is what you use. CMYK is
    used for prints and nothing else, it is a subtractive color space where
    you start with a white sheet and subtract the colors you don't want.
    Any time you print to an inkjet printer the photo is converter into
    CMYK before it is sent to the printer, most often by the print driver.
    For monitors CMYK makes no sense since it is an additive display
    device.

    Then there is the whole area of color spaces and color profiles, which
    among other things can help you get the print to look the same as what
    you see on the monitor, or more accurately shows you on the monitor
    what the print will look like.

    Scott
     
    Scott W, Jul 11, 2006
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  3. Bill Hilton

    AZ Nomad Guest

    CMYK is subtractive as would be the case when using dyes.
    RGB is additive as would be the case when detecting/generating light.

    You won't find any video screens that use CMYK either.
     
    AZ Nomad, Jul 11, 2006
  4. Bill Hilton

    Ken Weitzel Guest

    Hi...

    Wonder if it might not be helpful to think of it sort of paralleling
    a slide and a negative; where rgb is the slide, and cmyk is the
    negative :)

    Take care.

    Ken
     
    Ken Weitzel, Jul 11, 2006
  5. Bill Hilton

    George Kerby Guest

    Close. CMYK would be the *print* from that negative. A neg is still a
    transmission of light, whereas the print reflects light that strikes it.
     
    George Kerby, Jul 11, 2006
  6. Bill Hilton

    lubecki Guest

    Yes. It has to do with the way we see colors. The human retina contains
    only 3 types of photosensitive cells (called "cones"). They are
    sensitive to red, green, and blue light. Based on the relative outputs
    of those 3 types of cells, your brain creates a sensation of the full
    spectrum of color. Because of this fact, you can take any color you can
    imagine and "fool" the eye into seeing that color by shining an
    appropriate combination of red, green, and blue light. Digital cameras
    take advantage of this, and capture only the red, green, and blue
    frequencies out of the whole spectrum any scene emits. If they captured
    any other parts of the spectrum, the resulting picture simply wouldn't
    look (to the human eye) like the scene you're trying to capture.

    Besides, RGB requires only 3 sensors per pixel. CMYK would require 4.
    And CMYK is limited. There are colors that you can represent in RGB
    that you just can't print on paper, and can't represent in CMYK.

    RGB is used because of the way humans see colors. CMYK is used to make
    printing easier. Converting from RBG to CMYK is no problem as long as
    your monitor's color profile matches your printer's color profile.
    Again, this is just an issue of color matching the monitor and the
    printer. It's important, and it's a PITA to do, but it's not in any way
    a "flaw" of RGB.
    And that is a problem because...? Technology lowers barriers to entry
    into the business, which is in general a good thing. It gives the
    consumer more choice, and it favors good photographers, rather than
    just photographers with enough capital to invest into an expensive film
    photo studio.
    They shouldn't have any tint if you do your color matching correctly.

    -Gniewko
     
    lubecki, Jul 11, 2006
  7. A good and interesting thread. Thanks to the OP.


    JL
     
    Justus Lipsius, Jul 11, 2006
  8. Bill Hilton

    JohnR66 Guest

    I think Nikon and a few others tried a Cyan, Yellow, Magenta, Green color
    array over their sensors, but these cameras were never impressive and tests
    showed a yellow/purple fringing caused by the array (not the lens). When
    Nikon ditched that array and went RGGB (Bayer), the image quality/color
    fidelity improved.
    I've seen sensor technologies come and go, but the Bayer array seems to be
    the best balance. Foveon looked promising and was good resolution wise, but
    the stacked array didn't let much light to the lower cells, thus lower ISO
    noise was visible and to let any light through of one color meant the upper
    filtering was not as strong. This means heavy color processing is required
    and color fell to pieces in higher sensitivity modes.

    Many digital cameras have excellent color accuracy and post processing can
    improve on that.

    John
     
    JohnR66, Jul 12, 2006
  9. Bill Hilton

    Steve Wolfe Guest

    For monitors CMYK makes no sense since it is an additive display
    Except for LCDs, which start with white light, and subtract from it. :)

    steve
     
    Steve Wolfe, Jul 12, 2006
  10. Bill Hilton

    AZ Nomad Guest

    Except that they don't pile the elements on top of each other.
    You don't have a cyan one on top of a yelow one on top of a magenta one.

    What you have is a blue one next to a green one next to a red one. Being
    in close proximity makes then additive.
     
    AZ Nomad, Jul 12, 2006
  11. <snip>

    You claim to know a lot about color. Hmmm.

    All (electronic) color detection is done in RGB.

    Human vision is RGB also.

    (There is an analogue to Lab color in human
    vision as well, but that's another topic.)

    CMYK is for printing.

    It's the difference between additive color (RGB)
    and subtractive (CMYK.)

    CMYK is 100% device-specific. There is no unique
    representation of any given color in CMYK.

    Change the inks and/or paper, and you have
    a whole new CMYK color space.


    rafe b
    www.terrapinphoto.com
     
    Raphael Bustin, Jul 12, 2006
  12. Bill Hilton

    Jan Guest

    Photo printers (on photo paper, not the inkjet printers) work in RGB. They
    use 3 colour lasers.

    All (most?) devices which emit light work in RGB.
    Slides are in RGB (ever heard about 4 colour/layer CMYK slides?).
    Televisions and monitors are RGB.
    Scanners are RGB.

    Printers are CMYK, they reflect light of which they absorb part of the
    light.

    Jan
     
    Jan, Jul 12, 2006
  13. Bill Hilton

    bugbear Guest

    The film industry uses RGB - 3 colour (assuming you mean film as in movie)

    Only printing-on-paper uses CMYK, and it only uses
    K to overcome the real-world limitations
    of CMY inks and real-world paper.

    Try doing some research on "colour spaces",
    or read the PhotoShop manual on (CIE)LAB
    before arguing further.

    BugBear
     
    bugbear, Jul 12, 2006
  14. Although the paper itself uses CMY dyes to form the image, because it's
    a subtractive process.
    No, they are not. Slides are CMY, though there is no 4th black layer.

    Dave
     
    Dave Martindale, Jul 12, 2006
  15. Film is *not* CMYK, it is just CMY. There is no 4th black component.

    Printing *conventionally* uses CMYK because the colour characteristics
    of the CMY inks are not ideal, and the black you get from CMY
    overprinted does not look very good. So the printing plate creation
    process carefully removes some of the density that would have been
    produced by CMY and substitutes true black ink instead. But some colour
    halftone printing uses more than 4 inks for better colour.

    Anyway, both printing and photography are *really* working in RGB at
    some fundamental level. The colour you see is determined by the
    relative strength of long, medium, and short visible wavelengths of
    light. In a sense, your eye *sees* in RGB (after some internal
    processing).

    In the case of CRT or LCD displays, or a colour projector, the image is
    actually produced by adding red, green, and blue light that are
    controlled independently. This is additive colour synthesis, and for
    these devices you just use red, green, and blue light sources and
    control the intensity of each pixel. It's easy to think about.
    To control red intensity, you just control the red light source and
    don't worry about greeen and blue because they have separate paths to
    the screen.

    But film and printing use *subtractive* colour synthesis. You start
    with white light, then pass it through 3 (or 4) layers of dye or ink
    that are stacked one on top of each other, instead of being separated.
    In order to control red light, you need to use a dye that *absorbs* red
    but leaves green and blue unaffected - in other words cyan. Similarly,
    magenta is actually the green-controlling dye, while yellow is the
    blue-controlling dye. There's also an inversion involved, since to get
    more red light you need *less* cyan dye.

    Still, in a very real sense, film and printing *are* working in RGB,
    because they are controlling red, green, and blue independently (or as
    independently as flawed real dyes allow). It's just that the
    subtractive process forces the actual dye colours to be cyan, magenta,
    and yellow.
    TV colour reproduction is compromised in a bunch of ways that digital
    cameras are not. Some of this is for historical compatibility, some to
    keep the receivers cheap.

    By the way, I might have responded to more of your article if it had
    been written in paragraphs. But it's all run together in one block, and
    it's just too much work trying to tease the separate ideas apart before
    replying.

    Dave
     
    Dave Martindale, Jul 12, 2006
  16. Bill Hilton

    NerveGas Guest

    For monitors CMYK makes no sense since it is an additive display
    What? Proximity doesn't change the additive vs. subtractive nature.
    They start with white light from a cold-cathode lamp, and indeed
    subtract from it by altering their polarization.

    steve
     
    NerveGas, Jul 12, 2006
  17. Technicolor prints were CYMK. They printed the CYM on top of a faint black
    and white K image. See any technical description of Technicolor for example
    http://www.reelclassics.com/Techtalk/technicolor-article.htm for details.
    Current color positives are all CYM as far as I know.
     
    Harlo Peterson, Jul 12, 2006
  18. Bill Hilton

    sid derra Guest

    no answer to your questions, as they have been answered in mutiple
    variations already... i just wanted to tell you that i really enjoyed
    reading the opinion and some of the stories of someone who has been living
    that business for longer than i have been alive ;-)

    rock on.
     
    sid derra, Jul 13, 2006
  19. In each individual cell in the display, you start with white light and
    pass it through a red, green, or blue filter. That is indeed a
    subtractive operation, but it's just used to produce the raw light.
    Then the LCD cell controls the brightness of the light passing through,
    which might be considered subtractive but I think is better called
    modulation. However, this all takes place within each primary-colour
    cell.

    But the colour mixing process is additive. Each photon of light
    reaching your eye has gone through only one of the red, green, or blue
    paths, and other colours are produced by mixing those light sources in
    your eye. So the LCD is an additive colour display, no matter how it
    produces those colours.

    Subtractive colour displays pass each photon of light through all three
    colour-modulating layers before it reaches your eye, so the LCD panel is
    not a device that uses subtractive colour mixing.

    Dave
     
    Dave Martindale, Jul 13, 2006
  20. Well, OK. I was talking about modern "integral tripack" single-strip
    colour film, not Technicolor.

    By the way, I wonder how the Technicolor print "K" image was produced.
    I'd guess from the green B&W negative, since green is closest to
    luminance perceptually. You *could* produce more accurate luminance
    for the K image by a triple exposure from the three RGB negatives, with
    relative exposures adjusted, but it would be awfully complex to keep
    everything in register.

    Dave
     
    Dave Martindale, Jul 13, 2006
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