3 ms·

I could understand you have to calibrate a display if the connection between PC and display would be analog. I don't understand it in the digital age.

semi-extrinsic 9y ago
I also have this question. I mean, the ones and zeros that get sent over your DisplayPort/whatnot cable for some specific color in your favorite color space should be identical for all computers everywhere. Why don't we then just calibrate the monitors themselves, rather than the whole OS?
- dljsjr 9y ago
  Monitors aren't often calibrated from the factory or they are calibrated to be "subjectively" nicer looking, e.g. high contrast and slightly cool white balance to account for show-room floors. In addition to that the built-in options for configuration are often very simplified and have a coupling. Low resolution control plus simplified options means that you often can't dial in perfect color reproduction. Hence ICC profiles.
- lostapathy 9y ago
  We essentially are calibrating for the monitor’s version of the color not being 100% accurate. Yo’re right, in a perfect world the monitors would just be correct from the factory. In practice, monitors change color over time (much mire common in ccfl backlit monitors, i think) and even shift with brightness, so we have to do it “at runtime”
- pjmlp 9y ago
  Because light is analogue, our eyes are analogue and the light conditions of the living room is analogue, the paper where images are printed is analogue and so on. It is physically impossible to get an unique colour space across all surfaces.
grzm 9y ago
The display at the end of it is an analog device. The calibration confirms that the actual light coming out of the screen is an accurate representation of what the digital information thinks it should be.
dljsjr 9y ago
It's not about the signal it's about the physical display. Displays aren't calibrated at the factory. To use an LED-backlit display as an example, not every single LED in the world is created equally. Not every LED is going to give off the exact same wavelength for the same current value. Extrapolate this out to all the other components and this is the reason that your monitor has built-in physical controls for changing RGB/contrast/brightness values to begin with. Calibration accounts for this. As for why ICC profiles are used instead of just changing settings on the monitors, the OSD options usually don't offer enough fine-grained control to get things just right. Display makers are typically targeting main-stream consumers so they provide simple adjustment controls.
HelloNurse 9y ago
A digital communication channel allows faithfully sending an image to the display. Turning that data into colored light is another thing. Standard values of the voltages, currents, timings etc. that are applied to LEDs, liquid crystal pieces and other electronic components of the display in order to get the desired colors are only a starting point; a calibration that measures the differences between devices and compensates them is needed because of manufacturing and accidental differences.
theatrus2 9y ago
To add to all the comments here: the range of physical colors a monitor can display intentionally also differs (a low gamut, sRGB gamut, or one of several wide gamut standards). The video pipeline sends just 8 or 10 but values at the display, but the actual color seen can differ dramatically.

semi-extrinsic 9y ago

I also have this question. I mean, the ones and zeros that get sent over your DisplayPort/whatnot cable for some specific color in your favorite color space should be identical for all computers everywhere. Why don't we then just calibrate the monitors themselves, rather than the whole OS?

dljsjr 9y ago
Monitors aren't often calibrated from the factory or they are calibrated to be "subjectively" nicer looking, e.g. high contrast and slightly cool white balance to account for show-room floors. In addition to that the built-in options for configuration are often very simplified and have a coupling. Low resolution control plus simplified options means that you often can't dial in perfect color reproduction. Hence ICC profiles.
lostapathy 9y ago
We essentially are calibrating for the monitor’s version of the color not being 100% accurate. Yo’re right, in a perfect world the monitors would just be correct from the factory. In practice, monitors change color over time (much mire common in ccfl backlit monitors, i think) and even shift with brightness, so we have to do it “at runtime”
pjmlp 9y ago
Because light is analogue, our eyes are analogue and the light conditions of the living room is analogue, the paper where images are printed is analogue and so on. It is physically impossible to get an unique colour space across all surfaces.

grzm 9y ago

The display at the end of it is an analog device. The calibration confirms that the actual light coming out of the screen is an accurate representation of what the digital information thinks it should be.

dljsjr 9y ago

It's not about the signal it's about the physical display. Displays aren't calibrated at the factory. To use an LED-backlit display as an example, not every single LED in the world is created equally. Not every LED is going to give off the exact same wavelength for the same current value. Extrapolate this out to all the other components and this is the reason that your monitor has built-in physical controls for changing RGB/contrast/brightness values to begin with. Calibration accounts for this. As for why ICC profiles are used instead of just changing settings on the monitors, the OSD options usually don't offer enough fine-grained control to get things just right. Display makers are typically targeting main-stream consumers so they provide simple adjustment controls.

HelloNurse 9y ago

A digital communication channel allows faithfully sending an image to the display. Turning that data into colored light is another thing. Standard values of the voltages, currents, timings etc. that are applied to LEDs, liquid crystal pieces and other electronic components of the display in order to get the desired colors are only a starting point; a calibration that measures the differences between devices and compensates them is needed because of manufacturing and accidental differences.

theatrus2 9y ago

To add to all the comments here: the range of physical colors a monitor can display intentionally also differs (a low gamut, sRGB gamut, or one of several wide gamut standards). The video pipeline sends just 8 or 10 but values at the display, but the actual color seen can differ dramatically.