> The reason for this is that most fonts have been designed for gamma-incorrect font rasterizers, hence if you use linear space (correctly), then the fonts will look thinner than they should.
That's not true at all -- fonts are mostly designed for high-resolution printing where gamma is essentially irrelevant.
Fonts in small sizes can look overly thin on computer screens when rendered "correctly" as black-on-white because 1) bright white surrounding a black letter can "bleed" into it in our vision, 2) we've become accustomed to comparatively bold fonts in computer interfaces and so fonts designed for print look thin by comparison, and 3) when stems are less than a pixel wide and therefore render as gray, this also introduces contrast problems (less of a problem on retina screens).
None of these have anything to do with gamma. However, changing the gamma used in rendering actually does work as a "hack" to make letterforms darker with more contrast -- but it's actually entirely incorrect.
Also with regarding small fonts, font designers have long known that the smaller a font is, the thicker its strokes should be proportionally, so some fonts come in optical sizes. "Text" or "book" weights are "normal", while "display" designed for larger sizes is thinner, and the occasional "small text" size is even thicker (often intended for classified listings, historically).
If you look at typefaces actually designed primarily for computer screens rather than print, like Georgia and Verdana, you'll see they are indeed thicker, much like "small text" fonts.
> The reason for this is that most fonts have been designed for gamma-incorrect font rasterizers, hence if you use linear space (correctly), then the fonts will look thinner than they should.
That's not true at all -- fonts are mostly designed for high-resolution printing where gamma is essentially irrelevant.
Fonts in small sizes can look overly thin on computer screens when rendered "correctly" as black-on-white because 1) bright white surrounding a black letter can "bleed" into it in our vision, 2) we've become accustomed to comparatively bold fonts in computer interfaces and so fonts designed for print look thin by comparison, and 3) when stems are less than a pixel wide and therefore render as gray, this also introduces contrast problems (less of a problem on retina screens).
None of these have anything to do with gamma. However, changing the gamma used in rendering actually does work as a "hack" to make letterforms darker with more contrast -- but it's actually entirely incorrect.
Also with regarding small fonts, font designers have long known that the smaller a font is, the thicker its strokes should be proportionally, so some fonts come in optical sizes. "Text" or "book" weights are "normal", while "display" designed for larger sizes is thinner, and the occasional "small text" size is even thicker (often intended for classified listings, historically).
If you look at typefaces actually designed primarily for computer screens rather than print, like Georgia and Verdana, you'll see they are indeed thicker, much like "small text" fonts.