What really is R-YR, R-YB, G-YR, G-YB ?

[Sorry if these are basic questions, but I have not been formally trained in video where this may be taught in Video Systems 101.]


I got back into calibrating my Sony KDS-60A2020 this week while the wife is away on vacation. I got things looking pretty good according to the software using AVSHD and HCFR with an i1-D2. I did grey scale and CMS calibration.

I have questions that have bugged me for years whenever I get the chance to get into a calibration of CMS. What are the definitions for R-YR, R-YB, G-YR, G-YB? As an engineer, I want to know what is really being controlled by these adjustment, not just how to adjust them.

What I have learned from searching the net, including AVS Forums, is to adjust:

Color for Blue Luminance

Tint for Cyan position

R-YR for Red Luminance

G-YR for Green Luminance

R-YB for Magenta position

G-YB for Yellow position

Is R-YB defined as Red Luminance minus Blue Luminance? This works since Magenta position is along the Red-Blue side of the triangle. But then this logic doesn’t work for G-YB. Yellow is along the Red Green side.

Is G-YR a difference between Red and Green?

Is the “-“ not a minus sign? Is "Y" not Luminance? Am I over thinking this?

So what are these controls really adjusting? Or, how are they making the adjustment?

I am talking in general terms. The adjustment of a color decoder commonly refers to adjustment of these items. Sometimes written RYR RYB GYR GYB.

I would like to forget the brand and labling in a sevice menu and talk generic.

When I read a general CMS calibration article and it states
"Just to be clear, RYR is a red gain control and RYB is a red tint control, primarily affecting the hue of magenta. GYR is a green gain control and GYB is a green tint control primarily affecting the hue of yellow.

From this type of statement I conclude G-YR is adjusting the Lumance of Green by adjusting the gain of the Green amplifier (if we have an analog system) thus pushing the Green gun harder (if we have an CRT). But let's ignor the technology.
Am I correct that GYR controls the Luminance of Green?
Why is it designated G-YR and not just GY or GYG (like RYR ?)

Here is where my first confusion comes in. "GYB is a green tint control primarily affecting the hue of yellow." Is the GYB control moving the xy position of Green. I thought the position of Green (and all primaries) were determined by the hardware characteristics and not adjustable with a CMS. Am I wrong here?

If G-YB is adjusting the ratio of Green/Blue, why is Yellow primarily affected? Why not Cyan?


I imagine these designations are carry-overs from CRT analog TV days, but I am think the concepts are the same today.
I am trying to understand the concept of these controls, not what menu item in a service menu to use.

Thanks for any education here.

OK. Spent some time reading about Vectorscopes, but I still don't see coorelations. I'll keep looking.

OK, I have studied about Vectorscopes and now have more questions::

Does RYR adjust the lumanace or the Saturation of Red ? Since the vectoscopre is only reading chroma, I am now thinking it is saturation. Same for GYR.

But I still do not understand these designations. I have not seen G-Y on any scopes yet. And I don't know what the YB inducates.