How does a monitor display the CMYK color? Is it actually showing the true CMYK color?
Suppose I'm designing something for printing purposes. Then I need to stick with CMYK model. When ever I'm choosing color while designing, I'm setting color based on what my monitor shows me as CMYK. But Monitors don't work on CMYK. So, what my monitor showing is a conversion of that CMYK in RGB.
After reading little bit, now I understood that CMYK and RGB are not exactly convertible and there are always some differences. So, what I'm seeing is not the color I actually set. Right? If that is the case, because of deception by my monitor, am I setting the wrong colors? How are we supposed to design then?
This is based on a question regarding RGB to CMYK conversion.
say, RGB (86,92,214) the color in my image. Then monitor uses same values for displaying (lightning LEDs, LCDs or CRTs). Right?
A monitor can't show true CMYK. CMYK is reflective light, or subtractive color. A computer display is projected light, or additive color. They take up different (albeit overlapping) color spaces.
Your software does its best to emulate the CMYK colors converting them to RGB but it simply can't replicate them exactly.
"When ever I'm choosing color while designing, I'm setting color based on what my monitor shows me as CMYK"
As you're probably found out, that's quite a crap shoot. You can calibrate your monitor, which will help, but it will never be the same.
Your best bet is to get color samples from your printer. Bigger printers will often print out color grids showing you different CMYK mixes on various paper stock. Barring that, you can invest in some Pantone CMYK books that do the same.
If you use a regular printer, and tend to run larger jobs that require cropping/trimming, you can make these yourself by placing CMYK color grids in the gutters of your press sheets. Ask the printer to keep those for you when they trim them all.
It's not so much "how does the monitor display color" as "how does the software think it's displaying this particular color on this particular monitor." As they say on Facebook, "It's complicated."
Color gets to your screen through layers of software called color profiles. A color profile takes the raw numbers and interprets them for display or for printing. (If you're thinking, "Hey, you mean changes them?" you're right.)
Your application software is applying a particular color profile to the numbers, then the OS and/or your graphics driver apply another profile to decide how bright to make all the screen's red, green and blue sub-pixels. When you calibrate your monitor, what actually happens is that you (or the software you're using to do the calibration) creates a custom profile that gets applied by the OS before the image hits your screen. If your monitor doesn't have its own color profile, which many monitors don't, or if you never installed it, then the profile being applied will be "Standard RGB." Which will, in most cases, be wrong.
Applications such as Photoshop, Illustrator and InDesign have additional proofing profiles that you can use to "soft proof" an image. These try to imitate what the piece will look like when printed, even to the point of trying to account for the fact that paper doesn't reflect 100% of the light that falls on it. Corel may have a similar feature, if you dig around.