Can anyone explain color management?
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    Cool Can anyone explain color management?

    I'm an advanced PS user, but one concept that I know is important and that I want to comprehend (to the point of an EUREKA! moment) is Color Management / Profiles. I tried to read this page:

    http://www.computer-darkroom.com/ps12_colour/ps12_1.htm

    But it seems to talk more than teach. The go off into analogies and metaphors without giving the user basic information first. To explain 1 concept, they take the 40 sentence approach rather than the short summation for comprehension. I just can't learn this way; the more long-winded it is the less I follow.

    If someone can give me a short analogy maybe that will help me click. Much appreciation for any assistance.

    "Doing something half-assed more than once just makes you more of an ass."
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    Okay, here's the skinny on color management. It is very, very difficult to accurately reproduce colors.

    First you have the monitor. Not all backlights on monitors are the same shade of white, the raw colors on LCD screens differ from model to model (for example all the raw colors on my Cintiq look neutral compared to my Samsung), the brightness and contrast settings on monitors are different, and even the temperature in your room can affect the colors on your screen.

    And then you have printing: different inks can have a slightly different color to them, the pigments might not be colorfast (meaning they fade when they get old), and the paper also influences the way the colors look (shades are made with a half-tone dot pattern, so if the paper has a surface that absorbs the ink differently, you'll get different colors.

    The good news is that you can create a color profile that will act as a middle man between the colors in your Photoshop file and the printer to make sure your colors print the way you want them to. The color profile says which colors need to make lighter or darker so when they print they'll match what you see on your screen.

    For digital artists there's really only one thing you need to worry about: calibrating your display.

    That's it.

    The default color profiles for Photoshop are fine, and most printers that are worth anything (like the Epson Stylus printers) are made so they print colors quite accurately, and are checked against the Pantone standard. Monitors on the other hand are not. Your monitor is the place where you'll get the most inconsistency with your color reproduction.

    In practice I've had the best results with color reproduction simply by calibrating my monitor, leaving Photoshop's color management alone, and turning off color management on the printer driver.

    Sure, if you had advanced enough color management software and hardware, then you can create color profiles for your monitors, for Photoshop, and your printers so that the colors you see on the screen will be exactly to how you see them when printed. But that kind of gear costs a lot of money and is only worth it if you are running a big graphic design studio.

    I recommend getting a Spyder 3 Pro from Datacolor. They have some pretty heavy hitting color management hardware available too, but use that thing and it'll help a lot.

    If you don't want to buy anything, you can try setting up Adobe Gamma or your graphics card might have something, but with both of those you have to eyeball the white point of your monitor, but getting your gamma right will help.

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    OK, that makes sense.

    Also, images in PS are open into different COLOR SPACES, such as sRGB, right? And sRGB is capable of producing a set limited gamut of colors. Other color spaces may have wider or narrower spectrums of colors.

    So I need to calibrate my monitor, and I've heard good things about the Spyder 3 Pro. It will create a monitor profile then, right? So that my monitor better portrays colors properly on screen, right?

    So in PS, under color settings I set my RGB workspace, (sRGB), my CMYK workspace (US Web Coated SWOP v2) and my policies on what PS does in either workspace when a color profile is embedded in the document (preserve it or convert it to the working one)

    Is this right so far?

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    Yeah, the color space determines the color gamut. The sRGB gamut is limited to what a computer monitor can display, so that's why we use it.

    Yup, the Spyder will create a color profile for your video card and automatically apply it for you. The trickiest part is to make sure that your monitor's brightness and contrast isn't clipping your whites and darks while still showing the brightest white and darkest dark. You can use this page to check your darks http://www.lagom.nl/lcd-test/black.php and this page to check your whites http://www.lagom.nl/lcd-test/white.php while you fiddle with the brightness and contrast settings on your monitor if the factory defaults are not doing the trick. You'll want your monitor to show the full range of values before the Spyder software does the rest.

    And yes, use the sRGB and U.S. Web Coated SWOP v2 color spaces. My policies for all three are "Preserve Embedded Profiles." I'm pretty sure those are the defaults.

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    Another well known calibration device is Pantone Eye One Display 2. I've been using the Eye Ones for calibrating lots of monitors in the last 8 years (several iterations of the puck) and can recommend them.

    Of course you need a good display to start with...

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    I never thought about the monitor OSD controls clipping the viewed blacks and whites but that completely makes sense. The Spyder would be able to detect this because it sees from the same perspective I do "outside" the monitor.

    When I calibrate my monitors and make a profile for it, how do I got about embedding ICC profiles into my images to ensure they are set correctly as well?

    I have a 32" Sony Bravia as a monitor right now (which has issues generating seamless dark gradients) and a 22" Wacom Cintiq 21UX (which has issues with low brightness - 250cd/m2) I assume I can go through the calibration for each monitor, making 2 unique profiles to ensure they reflect colors accurately on both.

    "Doing something half-assed more than once just makes you more of an ass."
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    You will probably miss the whole point if you not understand the main concept which is a bit more advanced.

    The color management is a translation system which translates abstract RGB values of any color from a device (printer, monitor, scanner…) to its counterpart from a universal coordinates system which has been made to describe all the color that can see the human eye. So, one unique scale can describe all the colors from any device.

    Let’s imagine we need to see us in real life and you decided of the location where we will meet us. You are the image file and I am the monitor.
    So you described how to go there starting from your house, 50 miles to the north, 188 miles to the east and so on (that’s RGB values).
    My main issue is I am not living in your house, so I have no clue how to reach this location with such limited information. Now, you gave me an ICC profile! In this ICC profile, the position of your house is defined using latitude and longitude which come from a universal coordinate system. This system allows me to locate precisely any kind of point on earth without even thinking where I am coming from. So, with the coordinates of your house and the other information you gave me, I am able to translate the place where we will encounter us to latitude and longitude. Because I am a human being (and also a monitor) I need to translate those latitude and longitude to something I am able to understand, mainly, distance and orientation from the place I am coming from (monitors understand only RGB values). As you, I have an ICC profile that indicate me the coordinates of my house. So, from my location….1500km to the north, 250km to the west and at last (I intentionally used kilometers instead of miles here), you are there! I am able to display exactly the color you requested.
    That’s the way how works color management.

    Now let’s use the real word instead of analogy.
    The file is described by RGB values per pixels. These RGB values does not mean anything in our real world since it is impossible to know using such information what kind of red is a R255 G0 B0 because that’s depends of the color space used. As an example, you can see in a relative way the difference between Adobe RGB and sRGB color space.

    You can see the sRGB pure green (R0 G255 B0) is R144 G255 B60 in Adobe RGB color space. So RGB values are relative!

    Fortunately, the image file comes with an ICC profile which describes the color space used. Photoshop now is translating internally RGB value to real color coordinates using L*a*b* coordinate system (That’s the PCS -> profile connection space) that has been made to give a unique coordinate to any color visible by human eye.
    Now Photoshop needs your monitor to display this unique color, so it will read your monitor specific ICC profile that a hardware calibrator has measured. This ICC profile indicates what RGB value is necessary to get the requested color on your monitor (yes, Photoshop works internally with real color coordinates, Lab colors).
    Just for information, the profile connection space of your monitor profile is not the L*a*b* system, it uses the XYZ system but it is possible to convert coordinates from one system to the other (that why I used miles and kilometers in the analogy). Done!
    That works the same way with any device till they have their ICC profile. Thus, the color management has nothing to do with color correction but color translation.

    (this italic part is not important, it is just a side note)
    If I remember correctly, the main difference between L*a*b* coordinate system and XYZ system is Lab is describing brightness of colors based on human perception, that means with a relative approach instead of the absolute way using Luminance (XYZ). But I am not sure and that’s not important since that’s the job of color management module.
    The name of these 2 profiles connection space comes from their coordinates axis, L*a*b* is using L* from lightness of color, and a* and b* for chromaticity axis and XYZ system uses x, y and z.


    The L*a*b* system is easy to understand with 3D representation. Here two views of sRGB color space, I added some monitors color space for a direct comparison.

    The top view shows the chromaticity, basically, the angle gives you the hue and the length from the center gives you the saturation. The front view shows mainly the lightness, how bright is a color compared to another one.
    So if you take the white line (the Dell U2311H), you can see this monitor is displaying pure magenta too bright compared to real sRGB magenta. Hue is good but it is lacking of saturation. Its pure green is too dark also and the pure blue is too bright and too bluish compared to real sRGB blue.
    These colors are obtained after calibration, that means calibration does not produce right colors, only color management is able to achieve that.

    I wrote before about ICC files which are able to give real color coordinate for any RGB value of a color space (from monitor, from standard color space or anything else). In fact because of obvious technical optimization, it is impossible to measure 16,7 million of colors and describe this huge amount of data inside ICC files. So, ICC files contain only few measures and most of the colors are obtained using interpolation. I have no idea of the number; it depends mostly of the device. Printers need lot of measure since ink interaction is difficult to predict compared to monitor colors. So it is easier with monitor but the prediction depends mostly of how monitor is displaying colors. That is the reason monitor needs to be corrected.

    There is 2 parts in ICC file:
    1- Correction- The first part is used only by device which need color correction like monitors (this part is empty on device independent color profile like sRGB or Adobe RGB color space). It is based on gamma curve, luminance and color temperature. If this part is not accurate, the prediction made using the second part will be approximate.
    2- Description- The second part is used in every color profiles, it describes the color space. That’s the part the color management module will use for color translation. This part has no effect outside color managed programs. Contrary to the first part, it is impossible to get this one without hardware calibrator like colorimeter or most expensive, spectrophotometer. If the first part is used in the ICC file, the data of the second part is based on the device after correction.

    So, monitor calibration does not allow displaying right colors on two monitors but it allows your monitors to display correctly the colors according to their own color space. You can see in a relative way the native colors displayed by the monitor previously quoted:

    As you can see, there are some differences with sRGB.
    But, using color management, it will be possible to get the right colors. Here the result after activating color management.

    There is still difference because of colors out of monitor gamut (look at the image of monitor color space comparison). Colors are identical on intersection between monitor color space and target color space (here sRGB). For this reason, it is highly recommended to avoid color space too different from monitor color space.

    In my example, there are two wide gamut monitors which are able to display correctly Adobe RGB, for the others you need to stick with sRGB.
    Just a side note, but wide gamut mode from these two monitors will allows to get 100% sRGB colors in this example since their color space fully cover the sRGB color space.
    Quote Originally Posted by AegisKleais View Post
    When I calibrate my monitors and make a profile for it, how do I got about embedding ICC profiles into my images to ensure they are set correctly as well?

    I have a 32" Sony Bravia as a monitor right now (which has issues generating seamless dark gradients) and a 22" Wacom Cintiq 21UX (which has issues with low brightness - 250cd/m2) I assume I can go through the calibration for each monitor, making 2 unique profiles to ensure they reflect colors accurately on both.
    They are multiple ways to work with profiles:
    -If all your applications are able to use color management, you can use a standard working space like sRGB. sRGB is a device independent color space, that means in practice you can work easily on the same image using multiple monitors. So the colors you will see will not be the native colors of your monitor but the sRGB colors (or colors close enough your monitor can display). As non native monitor colors, some banding can appear in gradient but these artifacts are not located in the file but on your monitor only.
    Since sRGB is standard, it will not be an issue if you forgot to embed a profile with your image. You can add it later if necessary.
    -If you are using a program that is unable to use color management, that will not be an issue also because what you need for a color managed workflow is a way to translate RGB data to visible colors coordinates. So the translation can be obtained using your monitor profile (the description part). You will need to convert your image once it is done to an sRGB image (or an image using another device independent color space). The conversion is not lossless, that is one of the issue. The other issue is you cannot work accurately displaying your image on multiple device using the same colors.
    I am not sure if that what you were asking anyway.

    (the image posted here has been made for a future thread explaining color management and calibration if I am still motivated writing it lol )

    Last edited by hecartha; February 7th, 2011 at 12:06 PM.
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    hecartha-

    So you're saying that the sRGB colorspace dictates the color, but does so in a relative manner. With the embedded ICC profile, we now have a starting point and can use an absolute form of measurement in order to ensure the proper color that was intended was presented, right?

    If so, that really clicks and makes sense. It seems color spaces were not standardized (where 1 method to determine color was used to rule everything) - probably so because, as we were saying, monitors are but 1 form of output and each screen's production may result in different variations of the intended color (whic is why we'd calibrate monitors, correct?)

    I get what you mean by the device independence. I embedded a profile into an image, and then presented the photo in Firefox. i then went into Firefox's config and disabled color management and sure enough, the colors shifted. Before, it looked dead on, if not SLIGHTLY darker (but I think this is due to me not having calibrated my monitors)

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    Quote Originally Posted by AegisKleais View Post
    I never thought about the monitor OSD controls clipping the viewed blacks and whites but that completely makes sense. The Spyder would be able to detect this because it sees from the same perspective I do "outside" the monitor.
    Actually the Spyder won't "detect it" per se. There's only two things the Sypder will help fix: white point (the shade of white on your screen) and gamma (the value curve for each channel). If your black and whites are clipped then the Spyder will detect those colors as the pure blacks and pure whites that your monitor can output and nothing else. Also the Spyder only tests 8 (or so?) shades of gray, red, green, and blue, so clipping will still mess up your gamma on the black end and the right end because the Spyder only corrects those values (not every single value because it would take too long to run the calibration otherwise) and then interpolates the in-between values. Meaning that if your monitor is clipping the gray at 16,16,16, and the Spyder only checks 0,0,0 and 32,32,32, then you'll still get clipping.

    Again, the Spyder 3 Pro only corrects gamma, which may help some of the clipping, but not all. And it can't tell if the white could be whiter or the black could be blacker because your monitor's brightness and contrast is messed up.

    When I calibrate my monitors and make a profile for it, how do I got about embedding ICC profiles into my images to ensure they are set correctly as well?
    The profile that is created for your monitor only goes into your video card to change the colors you see on your screen. The idea is to get your monitor to be as close to the sRGB color space as possible.

    I have a 32" Sony Bravia as a monitor right now (which has issues generating seamless dark gradients) and a 22" Wacom Cintiq 21UX (which has issues with low brightness - 250cd/m2) I assume I can go through the calibration for each monitor, making 2 unique profiles to ensure they reflect colors accurately on both.
    Yeah, you can run the software on both. But again, the Spyder can only change the white point and gamma curves on your monitor (and actually, to change the white point your screen will get even darker to compensate). Even with both of my screens calibrated the raw red, green, and blue colors on my Cintiq look neutral and even have slightly different hues compared to my Samsung. When painting in Photoshop I go to Window > Arrange > New Window for [filename] and then move that window to my good Samsung screen, occasionally looking at it to make sure my colors are good because the Cintiq has mediocre color reproduction.

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    OK, so I need to max out my brightness on the monitor; that ensures that the monitor is putting out the brightest white it can, so Spyder can set it as the purest white and then adjust the gamma from that point forward.

    I wonder if Spyder help detect RGB values (ie, I detect a hint of red in colors, so we need to lower it) I have my monitors set to 6500K daylight.

    I hear ya on the Cintiq screen not being as vibrant as a Samsung; that's a darn shame

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    Quote Originally Posted by AegisKleais View Post
    So you're saying that the sRGB colorspace dictates the color, but does so in a relative manner. With the embedded ICC profile, we now have a starting point and can use an absolute form of measurement in order to ensure the proper color that was intended was presented, right?
    Right for the second sentence but I don't know where you think I wrote about sRGB color space which dictates the color...in a relative way? Huh? I could fix my explanation if you point me where you understood that.
    sRGB color space doesn't dictate anything, it is just a standard color space created by HP and Microsoft as a solution to make general consumer life easier when printing something. So most of monitors are aiming such color space.
    The main issue of this color space is it is unable to cover the whole gamut of standard printer color space for cyan (especially), magenta and yellow, that's the reason Adobe RGB has been created (or one of the reason).
    But standard printer color space is unable to reach the purest red, green and blue of the sRGB color space so when Adobe RGB introduces a wider gamut, it adds more color out of printer gamut color space.
    Anyway, Adobe RGB is a useful mode for monitor if you plan to use a printer color space has your working space because it will allows to display almost all colors available by your printer contrary to sRGB mode.
    Quote Originally Posted by AegisKleais View Post
    If so, that really clicks and makes sense. It seems color spaces were not standardized (where 1 method to determine color was used to rule everything) - probably so because, as we were saying, monitors are but 1 form of output and each screen's production may result in different variations of the intended color (whic is why we'd calibrate monitors, correct?)
    What do you mean by that? Color spaces are standardized. Are you talking about profile connection space like CIE Lab or CIE XYZ?
    Quote Originally Posted by AegisKleais View Post
    I get what you mean by the device independence. I embedded a profile into an image, and then presented the photo in Firefox. i then went into Firefox's config and disabled color management and sure enough, the colors shifted. Before, it looked dead on, if not SLIGHTLY darker (but I think this is due to me not having calibrated my monitors)
    That proves only one thing, the profile you added on the image uses a different color space than your system profile.
    Now I don't know how you get your system profile. Some monitors come with generic profile or you created one using your OS. In any case, it is probably inaccurate without using a hardware calibrator.
    Quote Originally Posted by Metsys View Post
    The profile that is created for your monitor only goes into your video card to change the colors you see on your screen. The idea is to get your monitor to be as close to the sRGB color space as possible.
    Not sure if I am taking this sentence out of context but the profile created with a spyder3 or any other colorimeter doesn't modify only the display. As I said in my previous post, it creates a specific description of the monitor color space and this description is used to display the right colors based on CIE XYZ coordinates.
    Now it is impossible by color correction using a colorimeter (or anything else) to get your monitor closer to the sRGB color space. The calibration process does not allow to edit color space. Such operation can be done only by the hardware of your monitor if your monitor allows that. That's the reason when you are using wide gamut monitor outside of color managed application, you get those over saturated colors even using calibrated monitor.
    Quote Originally Posted by Metsys View Post
    Yeah, you can run the software on both. But again, the Spyder can only change the white point and gamma curves on your monitor (and actually, to change the white point your screen will get even darker to compensate). Even with both of my screens calibrated the raw red, green, and blue colors on my Cintiq look neutral and even have slightly different hues compared to my Samsung.
    It is needed to calibrate every monitor and again, the calibration software creates a specific description of available colors. You can load ICC profile and observe what the calibrator has done using for example such online application (ICCView). Colorsync on MacOS has a pretty viewer also. Windows XP with its Color Control Panel Applet has such a tool but it has been removed in Vista and Windows 7.
    Could you please post the profile made for your cintiq, I am curious about its color space.
    Quote Originally Posted by AegisKleais View Post
    OK, so I need to max out my brightness on the monitor; that ensures that the monitor is putting out the brightest white it can, so Spyder can set it as the purest white and then adjust the gamma from that point forward.
    hum, what are you trying to do exactly?

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    Quote Originally Posted by hecartha View Post
    Could you please post the profile made for your cintiq, I am curious about its color space.
    It's attached.

    Attached Files Attached Files
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    Wow, what a bad color space!
    In fact it is as bad as cheap laptop screen.
    Here is what it looks like:

    There is color shift almost everywhere and lot of problem with color brightness.
    That's normal than even the cheapest desktop monitor can do a better job.
    Concretely, here is how looks the same pure color compared to their sRGB


    For such difficult case, color management can help a little bit but it can't make miracles since there is too many colors out of sRGB gamut.


    Without color management, Photoshop will use the same RGB values for displaying the colors

    But with color management, Photoshop will try to preserve as many colors it can (colors located on the intersection between the two color space).

    The colors out of gamut will be wrong and mostly it will add banding and weird artifacts.

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    hecartha-

    Relative meaning it's relational to itself. For example if you had 2 folders, Folder A and Folder B, and in each was a file called hello.html, to get to the hello.html RELATIVELY from Folder A, the path would be ../Folder B/index.html. (The '..' says 'go up a directory from where you are, then go into the 'Folder B' folder, then the 'index.html' file.)

    This "relative path" only works for files in Folder A. An ABSOLUTE path doesn't care where you're starting from, it looks like "/Folder B/index.html". The '/' says "start at the top (a uniform starting point) and then go into Folder B and then index.html. That's "absolute".

    What I meant by "color spaces are not standardized" is that they don't relate the color they represent in a global language. They use different coordinate systems or means to express the color that's chosen in their gamut; so it's "non-standardized" in that manner.

    I'm merely wanting to go through the process of getting as accurate color representation as possible on my monitors.

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    I know what means relative since I used many times in my first post (remember my analogy about two persons trying to reach the same place...).
    But I still don't understand what you mean by sRGB dictates colors in relative manner. Since that's what you think I have written, it is a bit annoying to not be able to understand...anyway, if that's not important, that's not important~
    Quote Originally Posted by AegisKleais View Post
    What I meant by "color spaces are not standardized" is that they don't relate the color they represent in a global language. They use different coordinate systems or means to express the color that's chosen in their gamut; so it's "non-standardized" in that manner.
    After reading a lot about all the attempts to create the ultimate model, you may think differently. The reason of many systems comes from different needs.
    I am not sure since it is just a supposition based on something I remember vaguely but it is maybe one of the reason of XYZ and L*a*b* system:
    -XYZ is used for screen profile because it is precise just like a colorimeter measuring wave length of light. When you calibrate a monitor, the colors are measured considering a white luminance. That means if you change the luminance increasing brightness of your monitor, you will need to calibrate again your screen because our technology are far to be perfect. The relationship between colors can variate a little bit changing brightness (there is gamma stability test that show how reliable is a screen when changing its brightness).
    So, colors are defined considering an absolute luminance.

    -Now, Lab system is closer of what we are seeing because a stable luminance does not make sense when talking about printed work. The luminance will change according to the amount of light is bouncing on the printed image so it uses a relative approach.

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