Font Rasterization on E-Readers

Lukas Horn

Hello,

Does anyone of you have nearer Information about the rasterization of type on different e-readers? My only clou is, that kindle uses iType from Monotype but that doesn’t say anything about the rasterization in and of itself. (Apple B&W, Apple Greyscale, Freetype B&W, Freetype Greyscale,  MS B&W, MS Greyscale – maybe for the E-Ink series?)

If you would design a typeface for e-readers, what kind of hinting would you concentrate on to get a nice and smooth result?

Has anyone of you ever done a type project for this kind of device who could say more about it?

Is there a good workflow you would recommend (working with Glyphs or with Fontlab etc.)?

I’m working on this subject for my bachelor thesis and I would be grateful for any information. The typeface I design should be suited for the e-ink display devices with a low resolution (something between greyscale and B&W) and also for the e readers with color screens. 

Thanks a lot!

Lukas

Viktor Rubenko

Indeed, this is a very interesting question.

The problem is that each company uses its own software with its own settings and availability of font formats, so the difference in displaying fonts may depend not only on the brand, but also on the models of one device or system firmware.

It seems to me that it is impossible to make the perfect font for all e-books at the same time. It is necessary to proceed from the needs of the customer, who can give a certain technical task for their devices.

Christian Thalmann

I was just worrying about the same question recently. One of my current typeface projects (Ysabeau) is aimed at body copy, in particular in electronic media, and so I've been test-reading it on my Kindle. It worked really well, so far, except for some baseline inconsistency in the bold. I've switched to TTF fonts in the meantime, and that solved the problem. Looks like Glyphs' autohinter does a good job there.

Viktor Rubenko

Christian Thalmann said:

Looks like Glyphs' autohinter does a good job there.

What is actually ttfautohint library embedded in Glyphs.

Jens Kutilek

I have a Tolino e-reader and use my own OTF font on it. I noticed that the PostScript hinting settings do have a visible influence on the rendering. I suspect it is using the FreeType rasterizer.

Most e-readers have a screenshot function, so you can compare differently hinted versions of a font, and take screenshots to overlay them on the computer which makes it easier to spot changes.

Jens Kutilek

The Kindle is using the Bookerly fonts designed by Dalton Maag. If you can get your hands on the fonts, you will noticed that they are completely unhinted TTFs, so the Kindle must be using some kind of autohinting while displaying the fonts, like macOS does.

Google Play Books also uses a custom font, Literata by TypeTogether. The fonts are on Github though I don't know if it is the same version as used in Play Books. The fonts are also unhinted TTFs.

Mike Duggan

with regards to the Kindle, I would not be at all surprised if it used just antialiasing, and no hinting, as the newer versions offered better display resolution. in my experience, hinting add the best value somewhere in the ranges of 96ppi - 150 or 160, then greater than that, no hints,  antialaising + a good solid typeface with open features will work well on screen.