Question about color spaces

[onurbey]

Is color space information is sent to the monitor or just the bit depth? For example how does a monitor know when to display srgb or dci-p3? And if you are only limited to 8 bits per channel will you lack out of some colors if displaying dci p3 or bt2020? Like how does the monitor know the difference between srgb and bt709 if they have the same possible amount of colors?

[Glenwing]

6 hours ago, onurbey said:

Is color space information is sent to the monitor or just the bit depth?

Color space information is not transmitted, generally speaking.

6 hours ago, onurbey said:

For example how does a monitor know when to display srgb or dci-p3?

It doesn't, you have to tell it what to do manually, through the monitor menu.

6 hours ago, onurbey said:

And if you are only limited to 8 bits per channel will you lack out of some colors if displaying dci p3 or bt2020?

The full color range is determined by your color space settings and is not affect by the color depth. If you set the display to DCI-P3 gamut, then the 8-bit value 255 for red will correspond to the maximum red intensity defined in the P3 gamut. If you set the display to sRGB mode, then red 255 will correspond to the maximum intensity of red defined in sRGB. Lower color depth will result in few steps between 0 and maximum intensity, so less granularity in selecting colors. But the range (minimum and maximum intensity) of each color is not affected by color depth.

6 hours ago, onurbey said:

Like how does the monitor know the difference between srgb and bt709 if they have the same possible amount of colors?

The color space setting in the monitor menu controls how the RGB values 0 to 255 are mapped to what output colors.

[Mihle]

Monitor can't detect what colour space what it detects is supposed to be.

 

Either you can set settings on the monitor that fits with what the device connected to it is sending.

Or you tell the PC that input to the monitor makes what colour, with something called a colour profile. But even then the monitor does not know if you are using a colour profile or not.

 

And, 8 vs 10 bit is not directly connected to colour space. A monitor can be 8 bit have and wide colour space, or 10 bit and not have a wide one. 

 

I do believe the monitor can detect if it receives 8 bit or 10 bit signal tho if I remember right. But that is not the same as colour space.

[onurbey]

14 hours ago, Glenwing said:

 

The full color range is determined by your color space settings and is not affect by the color depth. If you set the display to DCI-P3 gamut, then the 8-bit value 255 for red will correspond to the maximum red intensity defined in the P3 gamut. If you set the display to sRGB mode, then red 255 will correspond to the maximum intensity of red defined in sRGB. Lower color depth will result in few steps between 0 and maximum intensity, so less granularity in selecting colors. But the range (minimum and maximum intensity) of each color is not affected by color depth.

But for example in wide gamut test website I can do view both srgb and dci p-3 just by adding a dci p3 color profile to windows color management. So you say that srgb will never be 100% correct when dci-p3 mode is added to Windows color management or by selecting dci-p3 mode through monitor menu.

[Glenwing]

1 hour ago, onurbey said:

But for example in wide gamut test website I can do view both srgb and dci p-3 just by adding a dci p3 color profile to windows color management. So you say that srgb will never be 100% correct when dci-p3 mode is added to Windows color management or by selecting dci-p3 mode through monitor menu.

Color management will adjust images before transmitting to the monitor to remap colors onto their equilvalent values in the larger gamut, with the assumption that the monitor is set to display the larger gamut. For example, if sRGB red 255 were equivalent to red 245/green 10 in P3 (I don't know what it actually is), and you had images tagged as sRGB in metadata with a P3 profile loaded in Windows, it will convert the RGB values to whatever the closest equivalent value are in P3, based on the ideal representations of each gamut. Then it sends those RGB values to the display. What shows up on the display is up to the monitor, if you don't set it to P3 mode, and all the RGB values have been converted to their P3 equivalents based on your color profile loaded in Windows, then the output will simply be incorrect.

[xg32]

On 8/12/2023 at 3:29 PM, onurbey said:

Is color space information is sent to the monitor or just the bit depth? For example how does a monitor know when to display srgb or dci-p3? And if you are only limited to 8 bits per channel will you lack out of some colors if displaying dci p3 or bt2020? Like how does the monitor know the difference between srgb and bt709 if they have the same possible amount of colors?

disclaimer: not 100% sure on any of this,

 

8bit or 10bit on the monitor affects gradient and can affect image quality and accuracy, an 8bit monitor can be wide-gamut, but not something i'd use outside of some old hdmi 2.0/dp1.4 without dsc limitations. my ps5 is on a hdmi 2.0 port with 4k 60hz hdr 8bit.

 

Monitors have an internal LUT that determines the exact colors it can display, this isn't advertised as much as it doesn't matter for low/mid range and worse, consumers don't care. Though in my experience, monitors with higher LUT has slightly better imagine quality even displaying srgb sources.

 

LUT is also seperate from the color space the monitor can actually cover. I've had the pleasure to work with a hdr monitor that had completely unlocked settings (x27) and i can force colors that were out of its range by enabling hdr (something like a gamma adjustment by windows and in-game) twice or even 3 times.

 

The monitor doesn't have to "know" the color space of the source, if it's sent something that's only in the 2020 space, it should be able to display it unless it's out of range.

 

Despite all this about color space, bit-rate, LUT and color coverage, contrast can easily distort the colors, which is why an oled panel with near-full p3 coverage and unclamped colors is preferred, mini-led does have more (excessive?) color coverage, higher brightness but comes with blooming issues.

 

Looking forward to 32inch 4k oled panels.

[onurbey]

On 8/14/2023 at 12:10 AM, Glenwing said:

Color management will adjust images before transmitting to the monitor to remap colors onto their equilvalent values in the larger gamut, with the assumption that the monitor is set to display the larger gamut. For example, if sRGB red 255 were equivalent to red 245/green 10 in P3 (I don't know what it actually is), and you had images tagged as sRGB in metadata with a P3 profile loaded in Windows, it will convert the RGB values to whatever the closest equivalent value are in P3, based on the ideal representations of each gamut. Then it sends those RGB values to the display. What shows up on the display is up to the monitor, if you don't set it to P3 mode, and all the RGB values have been converted to their P3 equivalents based on your color profile loaded in Windows, then the output will simply be incorrect.

Hmm, got it. Color managements job is to convert the actual color values according to the monitors color values. I have both dci-p3 and srgb under the icc profile in WCM.