CMYK value for skin tone?

Discussion in 'Digital Darkroom' started by todd_phillip, Jul 14, 2007.

  1. I have been trying to adjust the yellow to magenta using curves...but some how I
    am not effecting the ratio between the two...
    My attempt is to increase yellow and maintain Magetna...which seems to me to be
    a simple process yet I am increasing both even though i am just ajusting the
    yellow in cmky mode??

    Any ideas of what I may be doing wrong?
     
  2. i never, never retouched in CMYK, always in RGB.

    But to answer your question, use a curve and go into the yellow section.

    Also make sure your screen is calibarted with a device, so you can judge by eye how the skin look, and if you like it. There is some recipe to get skin tone, but honestly caucasian people for exemple have not the same *recipe* in the flesh tone, so it could be hard to follow one of them by number only.
     
  3. google color correcting by the numbers
     
  4. why are you working in CMYK?
     
  5. He doesn't say that he is working in CMYK...

    There are many reasons why someone might do so and it used to be the norm. He could
    however just be looking for the correct CMYK numbers whilst working in RGB.

    Todd, you can use whatever color correction tool you wish. If you are having trouble with
    curve adjustments to get what you want, try selective color or some such. Keep your info
    pallette open and placed over where you wish to take readings. Also, take the color picker
    off of point sample if you are using it.
     
  6. Yes he does <...i am just ajusting the yellow in cmky mode..>

    ajusting the yellow in CMYK MODE..it seem pretty clear to me?! How could you use a curve in CMYK without being in CMYK?

    ____________________________________________________________________

    it used to be the norm when calibrated screen where not existing and people related on match print ; )

    there are certainly many reason why someone would want to correct in CMYK...but i dont know much that are good enough to convince me not to retouch a RGB file on a calibrated screen, using in need, a preview in CMYK that have been setup to my commercial press, ink and paper type.

    Since that there is not a *standart* CMYK recipe for skin tone, you migth be better to retouch for what you like, for a mood, for what you consider normal etc..using a calibrated screen.

    CURVE

    HUE SATURATION

    COLOR BALANCE

    are the kind of tools you migth need to use...in RGB.
     
  7. I've noticed similar symptoms when color correcting. On all skin images, the magenta is influenced by the yellow adjustment, some more than others. I don't know why this happens, nor do I really care to learn it today, but I have noticed that the effect is less apparent when the sample size of the color sampler tool is increased to 5 by 5 average, and not 3 by 3 average. One other technique is to move the sample point to a different position, near the original position, then making adjustments. It seems to me that with some images, especially underexposed images that have been brought up in processing, you just have to go back and forth on the yellow and magenta adjustments until you get the desired values. Much luck.
     
  8. Patrick, you are right. He is in CMYK. He may not have an RGB file however. Whether or not
    it is the norm anymore, those without CMYK retouching abilities (high end retouchers) are
    lacking very much - a big hole in their skillset. I don't know if this is true for you, but I run
    into quite regularly in junior retouchers here in NYC.

    While there is not particular exact numbers/standard there ARE numbers and values and
    ratios to use as a guideline adjusted for personal taste and mood.

    Anyway, Howard says some very good things here.

    Howard Owen, Mar 05, 2007; 05:11 a.m.
    Correcting skin tones in CMYK is an excellent idea. There are, in fact, numerous color
    corrections that can be accomplished in CMYK (or LAB) that simply cannot be duplicated in
    RGB. However, for skin, there is no need to *convert* to CMYK, you can just use the Info
    Palette with a CMYK readout. Here is a little post from Kevin Breckenridge on the
    percentages:

    Matching skin tones has driven many scanner operators into retirement.

    There is no magic formula or CMYK breakdown, but here are some general rules that have
    worked for me over the years.

    First let me state the obvious, every person has a unique skin tone color, even within
    specific ethnic groups the variety is limitless. Unfortunately CMYK, and offset printing only
    allows us a fraction of choices, and equally unfair you are often forced to stereotype
    people with specific CMYK break downs to trigger those every present memory colors hard
    wired in our brains.

    Take a look around the room, Caucasian, Asian, African American, Hispanic, East Indian,
    and Native American, all in reality don't have nearly the saturation of color we see in
    photographs and publications. So we have to cheat a little to give these images some
    punch, after all who wants a bunch of pasty smiling people on the cover of their magazine
    anyway!

    A good rule of thumb for most skin tones is to have the magenta trail the yellow and the
    cyan trail the magenta, very little black even in African American people. Black should only
    serve to add density to a prominent shadow areas, if you have too much it will neutralize
    what color you have when it hits the press, those pressman always run up the Black so the
    text looks sharp.

    Here come the stereotypical portion of color correcting skin tones:

    When I set up a scan for Caucasian people the Magenta trails the Yellow slightly and the
    Cyan in less than half of the Magenta.

    If I sample a quarter tone area the CMYK might look like this: Cyan: 10 Magenta: 25
    Yellow: 30 Black: 0

    Asian people get a little more of everything plus a slightly higher separation between the
    Magenta and Yellow.

    If I sample a quarter tone - mid tone area the CMYK might look like this: Cyan: 15
    Magenta: 35 Yellow: 45 Black: 0

    African Americans and people with darker skin tones get a slightly warmer treatment with
    enough cyan to keep it from going to red on press.

    If I sample a mid tone area the CMYK might look like this: Cyan: 25 Magenta: 47 Yellow:
    55 Black: 5

    The big trick is to mix it up a bit, I don't shoot for these numbers every time, I like to
    ensure the scan prints as close to the original as possible after all that's what a scanner
    operator gets paid to do, but if I have some creative license or the photo has poor color
    and overexposed, I apply these guidelines. I also watch the 3 quarter tones and shadow
    areas very closely, making sure they don't over saturate and become dominant. The skin
    tones should have a consistent Hue regardless of the values from highlight to mid tone to
    shadow. Don't make the highlight Yellow, the mid tone Brown and the shadow Red.

    Here is another link even mentioned in the same thread (http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00KCEm)

    http://www.smugmug.com/help/skin-tone
     
  9. Using an output color space (CMYK) that isn't what you're ultimately going to use to get
    skintone values is kind of silly. You can do this in RGB, using the working space all your
    images will be using. This CMYK technique is dated, really dated!

    Change the CMYK profile in Photoshop's color settings, your values change. Not real useful.
     
  10. Thankyou all for you help...Ellis I am working in CMYK for much of the reason Anthony had stated...
    I was referred to using Lab to do editing and started to read a book Photoshop Lab color which maintains lab to be a powerful work space to adjust color, contrast and sharpness then convert to RGB,...second being CMYK as it has a more indepth color range....I know this is incongruous to editing in the work space your printing in but Im exploring the different methods...And Anthony that is very similar to what I have been researching...I will take a look at the threads you posted...thankyou...and thankyou Patrick & Christopher
     
  11. Stop reading book....There is no point of retouching in LAB for the reason you state as you have all the tools in RGB to do the same.

    As for the CMYK having more indetph color?! i dont know where you read that, since is the smallest color space use for printing only (or i migth not understand what indepth color range mean?)

    You can explore and loose yourself in the labyrinth of color management...but let me hand you the map and a flashlight;

    Retouched in RGB anytime you can, in really need and if your life depend on it you might try to go in LAB, but if your image is well expose to start with there will be no need. As a professional photoretoucher i never had a chance to go in LAB for the past 12years, i must be lucky : )
     
  12. >As for the CMYK having more indetph color?! i dont know where you read that, since is
    the smallest color space use for printing only (or i migth not understand what indepth
    color range mean?)

    Agreed. Some are under the impression that because CMYK has a fourth color channel
    there' more 'depth' but that's simply not the case. CMYK is an output color space based on
    some CMYK printing device so its highly device independent. That means the numbers are
    solely based on some printing device (which? Is this the device you're ultimately sending
    the numbers to? Probably not). The gamut of most CMYK devices, certainly those
    described by Photoshop for ink on paper output are pretty darn small and vary
    considerably.

    As for LAB, it is a device independent color space. Its based on math done in the 1930's to
    define human vision. There are NO capture and output devices that work with LAB. It is
    useful for some purposes but converting into and out of LAB, certainly in 8-bits is going
    to toss a pretty considerable about of levels out of your original file (depending on the
    original color space). Much of the older techniques for working with LAB can be conducted
    using the Lumanice blend modes in Photoshop on the original RGB document.
     
  13. Anthony, thanks for the smugmug link:

    http://www.smugmug.com/help/skin-tone

    As mentioned in the article, working with cmyk for skin tones is much simpler. The relative values between the channels for each ethnic group are straight forward to understand and remember. This is not the case when working with rgb or lab values. The article credited Dan Margulis for this approach. Two other book authors using this approach are Eismann and Lee Varis (his Skin book is almost dedicated to skin tones). I won't call any of these authors "silly".

    Note that we are NOT necessarily talking about the benefits between working in cmyk vs other color SPACES. Instead, the point is skin tones are easier to understand and achieve with cmyk values. If you do not wish to work in the cmyk color space, you can remain in the rgb (or lab) color space, and still monitor the cmyk values in the Info palette.
     
  14. I respect Dan margulis for what he is, 15 years ago i had the chance (and the money) to attend at a 1 week seminar on color calibration and CMYK color corection, man it was hard and full of good info, thats put me in biz when i was 18! I was one of the few that color management and color correction inpired. Today, i dont see the point of retouching in CMYK with the tools *easily* at our hand, like a Eye1 or Monaco or else to calibrate our screen, therefore being able to see for real whats will come out.

    Robert have a nice trick, one i use to fine tune a file that will end up on commercial press, magazine (95% of my work); work in RGB, and look and the info palette to see what number you get. Also, you can get a preview of you color if you use PROOF SETUP..according you have a good CMYK seting for the job you intend to do.

    I think what you have to understand is it better to work in RGB, have a calibrated screen, and use the histogram and info palette to fine tune your image. But if you dont intend to go on press, i think you loose your time trying to get a *perfect* numbers skin tone, when you can just go with what you feel is rigth and appreciate your work.

    Sometime, the number could be rigth but the image could be boring...a warmer skin tone is not the norm, but it is more pleasing to see.
     
  15. >Today, i dont see the point of retouching in CMYK with the tools *easily* at our hand,
    like a Eye1 or Monaco or else to calibrate our screen, therefore being able to see for real
    whats will come out.

    Exactly! Just look at the display AND use the info palette but use numbers that make sense
    (the original color space or working space NOT some arbitrary output color space).

    As for smugmug article, my rebuttal and other points on this dated approach (and some
    good posts from others about RGB values for skin) can be found here:
    dgrin.com/showthread.php?t=65450
     
  16. Thankyou and points well taken...
    I would like to add that it is true starting with good exposure white balance ...screen calibration all are contributing factors to not needing intense editings but my purpose is to gain knowlege and explore what options are available so I can hone my editing abilities whether it is for subtle skin tone adjustments or more challenging editing problems...
    I am a believer of quality images from camera to print with as little editing as possible...
     
  17. Quick question for you Todd..do you have a calibrated screen with a device? and did your lightning environment is control?

    im curious, thanks.
     
  18. Yes to all the above...i use eye one device to calibrate my screen and shoot raw using GreytagMcbeth color checker...profoto strobes
     

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