Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Open Source Color Management Is Broken

lieberbiber.de

Post reply on HN
Print view View original

21–30 of 129 posts

Re: Open Source Color Management Is Broken

#21

Post by HelloNurse »

_trampeltier wrote: post #10
GuiA wrote: post #4

Earlier quoted context omitted.

If you do any professional color work, you want a color calibrated display. This ensures that the colors you see on your screen will be the same as the ones on your designer colleague’s screen, and the same as the ones that come out of the printer’s factory, for instance. Higher end displays are already pretty decently calibrated out of the factory, but if you want to be exact you will need to buy an external piece o…

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.

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.

Re: Open Source Color Management Is Broken

#22

Post by theatrus2 »

_trampeltier wrote: post #10
GuiA wrote: post #4

Earlier quoted context omitted.

If you do any professional color work, you want a color calibrated display. This ensures that the colors you see on your screen will be the same as the ones on your designer colleague’s screen, and the same as the ones that come out of the printer’s factory, for instance. Higher end displays are already pretty decently calibrated out of the factory, but if you want to be exact you will need to buy an external piece o…

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.

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.

Re: Open Source Color Management Is Broken

#23

Post by seba_dos1 »

theatrus2 wrote: post #19
mark-r wrote: post #12

If you write the calibration info to the video LUT, why does software also need to know about it? Isn't your monitor displaying perfectly calibrated sRGB at that point?

This is assuming all the content is sRGB, which is not a safe assumption especially if you care about color management to begin with.

If the content is not in sRGB, don't you need to actually know the contents color profile in order to convert it to sRGB? How does the monitor profile matter at this point?

(not challenging, just asking, I know next to nothing about color correction)

Re: Open Source Color Management Is Broken

#24

Post by ancientworldnow »

GuiA wrote: post #4
gigogkggi wrote: post #2

This all sounds interesting but I have 0 clue about what the author is talking about. Can somebody explain what is being talked about, what color calibration is and all? Not a designer, but a systems programmer. I do understand rgb, hsv colors but that's it.

If you do any professional color work, you want a color calibrated display. This ensures that the colors you see on your screen will be the same as the ones on your designer colleague’s screen, and the same as the ones that come out of the printer’s factory, for instance. Higher end displays are already pretty decently calibrated out of the factory, but if you want to be exact you will need to buy an external piece o…

Displays also drift over time. So even if you have a professional display calibrated at the factory it needs to be recalibrated a minimum of once per year with 6 months being preferred in a professional environment.

This is true with even the highest quality color critical displays like we use in film/tv color correction ($5-$50k+ for 25" panels).

Re: Open Source Color Management Is Broken

#25

Post by pjmlp »

seba_dos1 wrote: post #11

> Except that they only set it for the primary output. Turns out if you have multiple displays, the profile for the first one is put into the _ICC_PROFILE X11 atom, but the profile for the second one in the _ICC_PROFILE_1 X11 atom, for the third display in the _ICC_PROFILE_2 X11 atom, and so on. It’s just that nobody seems to do this. Sounds like an easy thing to fix. I'd suggest the author to try and make some patch…

Not everyone is a developer, and this type of comments is why everyone that cares about UI/UX design professionally, eventually goes back to Windows or macOS.

Re: Open Source Color Management Is Broken

#26

Post by pjmlp »

semi-extrinsic wrote: post #13
_trampeltier wrote: post #10

Earlier quoted context omitted.

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.

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?

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.

Re: Open Source Color Management Is Broken

#27

Post by giovannicarruba »

seba_dos1 wrote: post #20
Accacin wrote: post #7

Earlier quoted context omitted.

He wrote a pretty detailed blog article explaining his issues and how he got around them, this is all very useful information to someone who is looking to do something similar. Spending €100 also isn't an insignificant amount, and for that price I would expect what I'm buying to work properly.

I don't understand that attitude, that's a pretty low price for a niche open hardware device.

What attitude? Paying for something and then expecting it to actually work?

Re: Open Source Color Management Is Broken

#28

Post by wereHamster »

seba_dos1 wrote: post #23
theatrus2 wrote: post #19

Earlier quoted context omitted.

This is assuming all the content is sRGB, which is not a safe assumption especially if you care about color management to begin with.

If the content is not in sRGB, don't you need to actually know the contents color profile in order to convert it to sRGB? How does the monitor profile matter at this point? (not challenging, just asking, I know next to nothing about color correction)

You don't want to convert to sRGB, you want to convert to the display device color space (which in professional displays is often larger than sRGB).

Most desktop environments and applications assume that the source is sRGB, unless specifically tagged (in image metadata).

So you have two points: source (image, video) and reproduction device (display, printer etc). And you convert colors from the former to the later. sRGB may not even come into play if the source image is AdobeRGB and the display is a wide-gammut pro LCD display!

Re: Open Source Color Management Is Broken

#29

Post by serf »

pjmlp wrote: post #25
seba_dos1 wrote: post #11

> Except that they only set it for the primary output. Turns out if you have multiple displays, the profile for the first one is put into the _ICC_PROFILE X11 atom, but the profile for the second one in the _ICC_PROFILE_1 X11 atom, for the third display in the _ICC_PROFILE_2 X11 atom, and so on. It’s just that nobody seems to do this. Sounds like an easy thing to fix. I'd suggest the author to try and make some patch…

Not everyone is a developer, and this type of comments is why everyone that cares about UI/UX design professionally, eventually goes back to Windows or macOS.

That type of comment is also the underlying reason why Linux improves/fixes things at such an astronomical rate compared to either of the choices you listed.

It's not just saying "Hey you, go fix that." , it's saying "Hey everyone viewing this comment on a public page : this exists and needs to be fixed. Someone grab a wrench."

Re: Open Source Color Management Is Broken

#30

Post by serf »

giovannicarruba wrote: post #27
seba_dos1 wrote: post #20

Earlier quoted context omitted.

I don't understand that attitude, that's a pretty low price for a niche open hardware device.

What attitude? Paying for something and then expecting it to actually work?

The attitude that the cost gap between products in the same category will not be accounted for elsewhere in the user experience or product quality.

tl;dr : you get what you pay for.

Post reply on HN