What an excellent article. I can't think of anything (except the very esoteric) that it did not cover.
If I had to criticize, I wish it had talked a bit more about printer color profiles (although in this paperless, web-world we live in, perhaps printing is in fact esoteric).
Unlike displays, a printer can't be simply defined with three primaries and a white point. Printer profiles can be quite large as they rely on someone having printed out a copious number of swatches on a given paper type and then measured (with some kind of colorimeter) device independent color values for each swatch. Those are used to build a large table for mapping from device independent color spaces to the printer's gamut.
Those large tables make the profile so large. And then of course interpolation is still required when mapping from a device independent color space to the printer profile. (Now imagine too that you need a different profile for each type of paper you might want to print to since each can represent color differently — plain paper unable to get the levels of saturation that a coated paper can.)
What was shocking to me was just how small the gamut of a printer typically is when seen alongside that of a decent display.
Consider that, in print, you'll never see an image as vivid as you can display on a nice, modern display. (And then consider that there are colors in nature so vivid that even a modern display cannot represent them. Just look at how much color is outside the triangle on the CIE "shark fin" color representation.)
Also not touched on (did I miss it?), all the math presented to map from one color space to another, also allows for "soft proofing" — where in fact you might match to a printer ICC profile but then take the result and match again to the user's display to give you a "preview" of what will be lost when going to said printer.
jimnotgym · 14m ago
That reminded me of a time when a printer manufacturer approached my old team with this problem. They needed a custom driver for a certain region of the world. In this region in a certain industry they liked the highly saturated 'bad' colours from a competitor, and wanted theirs to match. Much paper and ink was spent on this.
pessimizer · 1h ago
> What was shocking to me was just how small the gamut of a printer typically is when seen alongside that of a decent display.
What was a nightmare for me when I worked in prepress was how hard it is to get a convincing purple out of a $20K printer. I used tricks which basically produced nothing like purple in a way that gave customers a good purple impression because the things with a closer actual resemblance to purple always looked awful.
fidotron · 41m ago
Purple and orange were/are common spot colours for that reason.
My father used to work on all sorts of R&D involving things like how much K to use in substitution of CMY without getting desaturated etc. It's a real rabbit hole, especially if you want to reduce the amount of ink used to prevent soaking the paper.
monster_truck · 57m ago
One of the tricks we used in situations that allowed it was to get paper that matched the most important color, this has other downsides but they are more manageable. They were always the last run before everything was taken apart and cleaned for maitenance.
jimnotgym · 40m ago
This is a great primer. I used to work in this field, but not as a colour scientist.
> So why do we have so many different color spaces?
I think there was a missing piece here. Different representations of colour are useful for different things. I'm not going to give any secrets away but...if your trade involves finding out how close one colour is to another, then something that represents colours as points in space could make the maths easier. Then if you wanted to know if one colour was brighter than another, then something that represents a colour with a separate 'brightness factor' would make that trivial.
evaXhill · 2h ago
Really great introductory article on color space in general, I really appreciate that they touched on perceptual uniformity and how we all perceive colors differently. It’s great to find out that applications like Oklab came out recently to fix this by manipulating the distances between colors to try compensate for human perception while also being more straightforward to calculate so that it can be used in real-time applications. Also the UI of this blog post was so aesthetically pleasing, that it was worth burning my retinas with the light mode
ChrisMarshallNY · 2h ago
That's a terrific article!
I spent the majority of my career at an optical equipment manufacturer, and we wrote a color management system to handle 48-bit color, before any OS manufacturers had it.
Non-trivial stuff, but powerful.
I know of at least one technology that works by converting to an esoteric color space, messing with image data there, then converting back.
jimnotgym · 9m ago
Indeed... and it was always a huge amount of fun to find that converting from one space to another was not always reversible without distortion!
tuzemec · 1h ago
Such an amazing article.
Hope the author continues with the rest of the content in the same manner.
If I had to criticize, I wish it had talked a bit more about printer color profiles (although in this paperless, web-world we live in, perhaps printing is in fact esoteric).
Unlike displays, a printer can't be simply defined with three primaries and a white point. Printer profiles can be quite large as they rely on someone having printed out a copious number of swatches on a given paper type and then measured (with some kind of colorimeter) device independent color values for each swatch. Those are used to build a large table for mapping from device independent color spaces to the printer's gamut.
Those large tables make the profile so large. And then of course interpolation is still required when mapping from a device independent color space to the printer profile. (Now imagine too that you need a different profile for each type of paper you might want to print to since each can represent color differently — plain paper unable to get the levels of saturation that a coated paper can.)
What was shocking to me was just how small the gamut of a printer typically is when seen alongside that of a decent display.
Consider that, in print, you'll never see an image as vivid as you can display on a nice, modern display. (And then consider that there are colors in nature so vivid that even a modern display cannot represent them. Just look at how much color is outside the triangle on the CIE "shark fin" color representation.)
Also not touched on (did I miss it?), all the math presented to map from one color space to another, also allows for "soft proofing" — where in fact you might match to a printer ICC profile but then take the result and match again to the user's display to give you a "preview" of what will be lost when going to said printer.
What was a nightmare for me when I worked in prepress was how hard it is to get a convincing purple out of a $20K printer. I used tricks which basically produced nothing like purple in a way that gave customers a good purple impression because the things with a closer actual resemblance to purple always looked awful.
My father used to work on all sorts of R&D involving things like how much K to use in substitution of CMY without getting desaturated etc. It's a real rabbit hole, especially if you want to reduce the amount of ink used to prevent soaking the paper.
> So why do we have so many different color spaces?
I think there was a missing piece here. Different representations of colour are useful for different things. I'm not going to give any secrets away but...if your trade involves finding out how close one colour is to another, then something that represents colours as points in space could make the maths easier. Then if you wanted to know if one colour was brighter than another, then something that represents a colour with a separate 'brightness factor' would make that trivial.
I spent the majority of my career at an optical equipment manufacturer, and we wrote a color management system to handle 48-bit color, before any OS manufacturers had it.
Non-trivial stuff, but powerful.
I know of at least one technology that works by converting to an esoteric color space, messing with image data there, then converting back.