Need Input Re My Output/Monitor/Color Management

[AndrewRodney]

Originally Posted by ChrisPerry

They are RGB - they don't have a colorspace so to speak.

Of course they do. All RGB and CMYK documents are in some color space. All RGB output devices and CMYK output devices produce some color space within that color model. You may not know what they are in which case you're in trouble. Your color appearance may be way, way off. You'd have to use the Assign Profile command and tell Photoshop or any other application what the color space is. Numbers alone, without a color space don't fully define color appearance.

Once you profile the display, you've defined its color space (that's all ICC profiles do). You define the gamut by virtue of defining the color space.

The reasons CRTs are 'better' for color critical work is more due to how they emit light than their gamuts. More and more of the newer LCD's exceed sRGB by quite a lot. They also produce a much higher luminance which can be an advantage. That you can't adjust anything other than the Fluorescent light in CCFL LCD's unlike the ability to alter the RGB electronics in a CRT is the real short comings of LCD's in comparison to CRTs.

[IraParis]

Thanks for all the responses, but I'm still confused, and frustrated.
Assume that I have three monitors. A cheap LCD, and mid priced LCD, and a $5000.00 "Professional" unit.
I profile each monitor using the Gretag Macbeth Eye One 2 software/hardware. I then "work" my files to get the desired result. Because of the differences in the monitors, there is no way that each display will look the same. I realize that a $5000.00 monitor isn't necessary, but it seems logical that the more accurate the monitor, the more accurate I can work the file.

[AndrewRodney]

A cheap and expensive display when calibrated to the same target values should produce very similar color appearance. There's viewing angle, purity and degree of banding that will separate the units however. Purity alone is a very important quality in any display. The best unit every built to counter this, a Barco Reference V (CRT) was able to adjust the purity of 25 quadrants using its mated colorimeter. Took awhile to do.

[John_Vito]

Most of my clients use cheap to mid range displays....mostly Dell and some Apple. ALL never calibrate/profile their monitors but I take it upon myself to do that for them once and while (six months) for free. I always feel I'm losing the battle with my clients' color management but help them the best I can.

It's very admirable that you want to produce the best possible file (I do also) and willing to spend many dollars on a top notch display and knocking your head against a wall too. I'm getting excellent reproduction and repeatable business using both a Dell and Samsung displays. Not sure what I'm trying to tell you other than send your clients the best possible image...try to help them along the way with color management, if appropriate, and let it go and move on!

[ChrisPerry]

Originally Posted by IraParis

Thanks for all the responses, but I'm still confused, and frustrated.
Assume that I have three monitors. A cheap LCD, and mid priced LCD, and a $5000.00 "Professional" unit.
I profile each monitor using the Gretag Macbeth Eye One 2 software/hardware. I then "work" my files to get the desired result. Because of the differences in the monitors, there is no way that each display will look the same. I realize that a $5000.00 monitor isn't necessary, but it seems logical that the more accurate the monitor, the more accurate I can work the file.

RGB 120,100,150 (or any color) should look the same on all three. Or mine or anyone else's that't been profiled/calibrated.

The issue you're having is that RGB is an additive color model - all three colors at 255 is white, no colors (0,0.0) is black.
CMYK and all printing is a subtractive color model, and uses 4, not 3, colors (CMYK - cyan, magenta, yellow and black). All colors make black. No colors makes white (or the color of the paper/substrate).
IF the monitor is calibrated and the printer is calibrated then you should see on screen what you see on the paper, assuming the white of the paper doesn't shift things (this is one reason you profile your printer for every paper you use).

See RGB color model - Wikipedia, the free encyclopedia and CMYK color model - Wikipedia, the free encyclopedia

Edit it quote from Wiki -

n color theory, the gamut of a device or process is that portion of the color space that can be represented, or reproduced. Generally, the color gamut is specified in the hue–saturation plane, as many systems can produce colors with a wide range intensity within their color gamut; in addition, for subtractive color systems, such as printing, the range of intensity available in the system is for the most part meaningless outside the context of its illumination. When certain colors cannot be displayed within a particular color model, those colors are said to be out of gamut. For example, pure red which is contained in the RGB color model gamut is out of gamut in the CMYK model.

from Gamut - Wikipedia, the free encyclopedia

[ChrisPerry]

Originally Posted by AndrewRodney

Of course they do. All RGB and CMYK documents are in some color space. All RGB output devices and CMYK output devices produce some color space within that color model. You may not know what they are in which case you're in trouble. Your color appearance may be way, way off. You'd have to use the Assign Profile command and tell Photoshop or any other application what the color space is. Numbers alone, without a color space don't fully define color appearance.

Once you profile the display, you've defined its color space (that's all ICC profiles do). You define the gamut by virtue of defining the color space.

There is a difference between color model and color space. RGB is a color model. sRGB and Adobe RGB are color spaces. The difference is the s and Adobe are defined - they specifiy what the actual value of "red" is and it is not necessarliy the same for both (probably isn't). A monitor uses the RGB color model, but may not be capable of displaying the entire defined color space. That is gamut, and not every CRt or LCD can display the entire gamut of a defined colorspace. As last as it's close it works, but for some critical things it may be worth the money to find a display that can output the entire gamut of the colorspace you need.

To pull from Wiki again...

A typical CRT gamut.
The grayed-out horseshoe shape is the entire range of possible chromaticities. The colored triangle is the gamut available to a typical computer monitor; it does not cover the entire space. The corners of the triangle are the primary colors for this gamut; in the case of a CRT, they depend on the colors of the phosphors of the monitor. At each point, the brightest possible RGB color of that chromaticity is displayed, resulting in the bright Mach band stripes corresponding to the edges of the RGB color cube.

pulled from Gamut - Wikipedia, the free encyclopedia

[AndrewRodney]

RGB is a color model. But when you have a device or an editing space (sRGB, ColorMatch RGB, Adobe RGB (1998), etc), you've got a color space DUE to the primaries having a defined scale. That's all a color space is, the scale of primaries within the big mondo color space we call human vision (the gamut of human vision, represented 2D using the CIE chromaticity plot above). Every display has a color space we can define as seen in your plot above. One simply needs to define the scale of the primaries as done here, the result is the color space and thefore the color gamut of the device. We can do the same with RGB working space as they are simply mathematically defined synthetic spaces where someone has provided a set of chromaticity values on the horseshoe shaped plot. The entire horseshoe shape is human vision defined mathematically based on some science done in the 1930's by the CIE.

A monitor uses an RGB color model just like nearly all printers use the CMY or CMYK color model. That doesn't tell us anything too useful. We only know if the color model is additive or subtractive. The monitor produces an RGB color space as defined above in gamut plot because an instrument has measured and defined the three primary chromaticity values (and now we have their scale within human vision and thus a color space). It like all other input and output devices (besides a human) can't capture or reproduce the RGB color model as a color space we humans see. And if we could somehow plot the color gamut of dogs or crickets, we'd see a different plot for which all the other color spaces could be defined by this big mondo boundary of visible colors.

Saying a display uses the RGB color model isn't real useful. Saying a display has 93 percent of the Adobe RGB gamut, then showing us the plot gives us all the information we need to understand the color space and gamut of the device AND tells us its in the RGB color model. Use color space descriptions whenever possible to define a device or editing space, it provides a lot more information.

Saying the speed limit in New Mexico is 75 is only partially useful. But there's no scale (equivalent of color space). You're telling me the speed model not the speed scale. When you tell me the speed limit is 75 miles per hour (or even miles per kilometer), you've provided the scale. Far more useful.