Add a pixel layer & brush something on it in any color other than grey. This is easy to see from this simple test:Ĭreate a new document with any RGB or CMYK color format. This means the conversion is non-destructive, but the embedded document is still converted to the parent's color space for use in the document it is embedded into. So for the benefit of clarification, you might be able to technically have RGB layers (specifically, embedded documents and placed images) within a CMYK document, but you cannot avoid the colour conversion that is performed to ensure those layers display correctly. A profile by itself, doesn't change the RGB or CMYK numbers it simply gives them a specific meaning, saying, in effect, that these RGB or CMYK numbers represent this specific color (defined in XYZ or LAB).īy the same token, a profile doesn't alter a device's behavior - it just describes that behavior. Raw RGB or CMYK values are ambiguous they produce diffent colors when we send them to different devices. But no matter what it describes, a profile is essentiany a lookup table, with one set of entries that contains device control signal values RGB or CMYK numbers- and another set that contains the actual colors, expressed in the PCS, that those control signals produce.Ī profile gives RGB or CMYK values meaning. Profiles are conceptually quite simple, though their anatomy can be complex.įor now, though, we'll concentrate on their function.Ī profile can describe a single device, such as an individual scanner, monitor, or printer a class of devices, such as Apple Cinema Displays, Epson Stylus Photo 1280 printers, or SWOP presses or an abstract color space. So you should always think of RGB or CMYK numhers as tuned for a specific device. Neither was designed as an accurate mathematical description of color: they're really control siganls that we send to our various color devices to make them produce something that we eventually experience as color. The RGB and CMYK models originated in the analog rather than the digital world. This even happens within the same make and model of television. They're receiving the same recipe but their different characteristics generate different visible results. You'll see 20 televisions all lined up, of various makes and models, all tuned to the same station, and all producing somewhat different colors. You can readily see this in any store that sells television sets. Likewise, if you send the same RGB file to 20 different monitors, or the same CMYK file to 20 different presses, you'll get 20 slightly (or in some cases, more than slightly) different images. If you give 20 cooks the same recipe, you'll almost certainly get 20 slightly different dishes as a result. You can think of an RGB or CMYK file as containing, not color, but rather a recipefor color that each device interprets according to it's own capabilities. Unfortunately, these mathematical models of color are quite ambiguous.
Most digital color is encoded to represent varying amounts of either R, G, and B or C, M, and Y, or, in commercial printing and some (but not all) desktop printers, C, M, Y, and K (for BlacK). With film and printing, we still manipulate red, green, and blue light, but we do so indirectly,using CMY pigments to subtract the wavelengths from a white background - cyan absorbs red light, magenta absorbs green light, and yellow absorbs blue iight - hence the term "subtractive" primary colors. In the case of true RGB devices such as monitors, scanners and digital cameras, we work with red, green, and blue light directly. When we reproduce color on a physical device, whether it's a monitor, a piece of transparency film, or a printed page, we do so by manipulating red, green, and blue light. reflective color models, & so on in different color spaces. I think that can be fully explained by the usual & expected differences in gamut, transmissive vs. So once we learned that, we really were not looking for anything other than an explanation for why the colors in an embedded document might look different from those in a stand alone version of that document. It was obvious that when I clicked Convert, nothing happened." But that turned out to be only because the file name included "CMYK," as mentioned here. The OP wrote here that "that the images are still CMYK, and verified by clicking on an image and seeing the CMYK file name still in the upper left corner. Also don't forget there can be bugs related to this and it's handling, which wouldn't be the first time. Thus we were looking if there is some way to detect then which color space is applied to embedded images and the like. That's right and was also my first thought, but then the OP said for embedded images, which might not be handled the same way here if they contain their own applied/embedded color profile.
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