Originally Posted by ndaa75
OK thanks for this Doug.
I get most of what youre saying, however the problem occurs when I have to set saturation. For example, if im trying to set the colour RED correctly im generally having to increase the red slider in order to increase the saturation level to the target point, however the consequence of doing so increases the luminance. Not sure how to get past this.
As I said in the original post, sometimes moving one control causes some other parameter to change. So you have to adjust another control (or all 3) every time you make one adjustment. You have 3 primary colors, red, green, and blue and 3 complimentary colors... magenta, cyan, and yellow. Each color has 3 controls (at least I've never seen a Samsung display with CMS and less than 3 controls per color). Those controls control hue (the color), the saturation (what you are trying to change), and luminance (how bright the color is). Sort of... as mentioned, those 3 controls may interact. So if you adjust saturation and luminance goes up, you have to adjust the luminance control lower to keep the color from getting too bright. When adjusting red, the hue control will likely move the measured red point closer to green when you move it in one direction or towards blue when you move the control in the other direction. The saturation control... sounds like you know what that does. The Luminance control will move the brightness of the color in question up or down.
So... let's say you adjust the saturation control to get red closer to the Rec709/HDTV coordinates for red, but red gets brighter while the saturation improves. You then lower the luminance control to get red brightness correct again. But that causes red to de-saturate again. So you make another move with the saturation control and again, you improve saturation, but red is too bright again. So you use the luminance control to make it dimmer, but that, again, de-saturates red. You are stuck in this cycle and can't get the saturation and luminance correct at the same time. This is where the "art" of calibration comes into play. Your TV is simply not capable of making the red point accurate. So you have to decide whether the saturation error or the luminance error is more obvious and live with one or the other. Another option is to leave half the error in saturation and half the error in luminance and live with that... I'd probably do the latter.
The other thing about errors, luminance errors in particular, tend to be more problematic if there are large swings in luminance errors... say red, green, and magenta are too bright while cyan, blue, and yellow are too dim... that's a bad scenario for image quality. You want them all within 10%-15% of each other (less if possible). So if you end up with red being too bright and there's nothing you can do about it, you should make all the other colors too bright also... not by a crazy amount, but you definitely don't want a situation where red is 30% too bright and some other color is 30% too dim. If I had a problem where red was going to have to be 30% too bright, I'd probably try to get the other colors to be about 15% too bright.
Using the Color control in the user menu MIGHT help with red saturation---or not. You won't know until you adjust it and re-measure and see if increasing Color allows you to get closer to the ideal red point while maintaining a more accurate luminance level. Color controls do different things in different displays so you'll want to measure ALL the colors after an adjustment of the Color control because the Color control might help you fix one problem, but it could create a problem with some other color. Our vision is most sensitive to Green so you want green to be as accurate as you can make it. Cyan and Yellow should be the next most accurate colors. Red and magenta should be next in line for accuracy, and blue errors would be the least-obvious errors. But large errors in any color will be visible so you have to keep things in balance (again, part of the "art" of calibration that you can't learn in descriptions of how to calibrate).