Preparing fonts for eInk devices

[GERGE]

I have noticed long ago that when I put font files from my typeface library to my Kobo, I usually get terrible results, only few of them work really well, some more work somewhat blurry, rest are terrible.

After years of using them like this and sticking to some nice ones that work well, I thought something I should have thought of the first time I got my hands on an eInk device: What if their pixel alignment are different? Then of course my typefaces wouldn't work as ACCESS and RMSDK read hinting instructions (I don't know about Kindle at all). Those instructions are prepared for LCD and LED screens after all.

So, I checked the screen; it appears it is way more than simply being different, it is completely weird: https://www.mobileread.com/forums/sho...56&postcount=3

It is the same with newer models too.

Learning this, I told FontForge to render font files with old style kerning (for Kobo's ACCESS) and to discard hinting instructions. All the typefaces that seemed so terrible are as beautiful as they should be now.

I think most of you would already know this, but there might be some slow people like me who haven't noticed yet, so I thought I should tell you.

[roger64]

I know nothing about this and do not know how to strip kerning instructions. But it sounds pretty interesting.

I stick to Kobo because it allows me to use my default font of choice with a little added font-weight (thanks TypeGenius).

Could you upload a font optimized for e-ink (if it's free of course)?

[GeoffR]

I tried removing the hinting on a few fonts, the only one so far that improved as a result was Gentium Basic. It was awful before, and the improvement was dramatic.

However I suspect this is just because the hinting in the original font was so very badly done, it looks better without hinting on my LCD laptop screen too.

Here are screenshots of Gentium Book Basic from my Glo (epub reader), with and without hinting:

[GERGE]

So, maybe this is because most free typefaces' and old typefaces' hinting instructions are not up to par. Most of typefaces I own are old, and I tried with free ones too.

Charter I have improved too, for example.

Maybe this is just something to check when type renders terribly.

[GERGE]

I did more testing, if the hinting is done for the single purpose of rendering small sizes, it usually ends up with bad results on eink, while eink renders general hinting for pixel alignment much better. It probably does some sort of conversation for its weird pixels. Therefore, bad hinting (which might not be evident in LCD screens but mucks up the conversation, I think) or hinting specifically for small sizes render badly.

There is a simple test to see which one your fonts have: if the font file you use greatly changes the shapes of the rendered glyphs in different sizes, you might be better of removing the hints. If the shape changes but difference isn't that great (you will understand what I mean when you see it) you might want keep it but hinting doesn't create much of a difference in eink.

Also, if the type seems unusually thin compared to LCD rendering, remove the hintings.

Font files prepared for web (which is much different than web enabled font files) are usually works well with eInk, but font files for printing are usually are not.

[GERGE]

By the way, FontForge's Change Glyph option sometimes helps greatly. Here is an example of its use with its default settings:

This is without any editing: http://drop.muratcansimsek.com/Scree...2010.29.12.png

This is after using it: http://drop.muratcansimsek.com/Scree...2010.30.24.png

Difference seems very minimal but it is actually very sane (in this example) and does sometimes much better work than device-side weight changing. What it does is making finest details of the glyphs more rough. It does not damage the typeface but eliminates finer details that cannot be accurately produced on eInk screens, details which are there for high quality printing.

Of course, it will make many typefaces worse, source glyphs must be very detailed for it to work, like the great Adobe Text (I don't think Robert Slimbach is capable of producing anything even slightly bad) in my example.

But it should never be used to change the weight, because then it also changes the height.

[GERGE]

I took some sreenshots, difference can be seen better.

This is without hints: http://drop.muratcansimsek.com/wh.png

This is with hints: http://drop.muratcansimsek.com/h.png

I think one without hints are infinitely better than the other one.

[fjtorres]

Check this from the digital reader blog:
http://the-digital-reader.com/2015/0...d-equal-video/

[GERGE]

This post from hvas illustrates my point nicely:

Originally Posted by hvas

You might not like unhinted Literata but it's objectively closer to the glyphs of the actual font. The hinted version is weirdly squished to align to a different kind of screen than e-ink.

Again though it all comes down to personal preference. Also it's a lovely new font that I hope ends up replacing Georgia on e-readers.

[kacir]

Originally Posted by GERGE

I took some sreenshots, difference can be seen better.

This is without hints: http://drop.muratcansimsek.com/wh.png

This is with hints: http://drop.muratcansimsek.com/h.png

I think one without hints are infinitely better than the other one.

The one without hints has the xheight of letter 'i' a pixel shorter than letter 'r' and 'v' in the word "drive".
That would drive me nuts, because my eye stumbles when it finds such irregularity. This is exactly what hinting is supposed to prevent.

[GERGE]

It doesn't look like that on the screen, screenshot feature isn't working perfectly:



Sorry about the bad focus =)

This is the same type, but I took a better photo: http://drop.muratcansimsek.com/IMG_20150520_144417.png

[PeterT]

@Gerge: If these shots are from your Kobo why not enable the Screenshot hack?

Originally Posted by davidfor

You add the following to the configuration file:

[FeatureSettings]
Screenshots=true

Then using the power button will take an screenshot. The side-effect is that you can't use the power button to put the device to sleep or turn it off.

The screenshots are saved in the root of the main memory.

[GERGE]

I did, i was weird. Don't know why. Look at the #10.

[howyoudoin]

I have removed hinting from all my side-loaded fonts. In some cases the result is a much sharper font. Some fonts appear thin and spindly with hinting removed, and I rectify that by adjusting the weight and sharpness of the font on the device (I have GeoffR's patch installed to permit this).

[John F]

Is a "screen shot" (a direct image dump) sufficient for evaluating font quality for high dpi eink screens? I see "font designed for eink screen", but what does that mean?