I'm a hawk about typography and readability, so I returned my first Kobo Touch within hours of receiving it - the two fonts offered did not meet my needs, and were nearly unreadable when set to suit my reading.
However, after seeing the huge advance Kobo made with the 1.9.5 software update, I ordered another one, and received it yesterday.
After updating it and loading a few books onto it, I spend most of the rest of the day playing with type, to see what I could do to meet my needs. Here's where I'm looking for, and where I'm at with it.
I am a speed-reader. I was once been tested reading newspaper material at 3000 wpm, with excellent comprehension. I've also developed Postscript fonts and scalable logos for both low-res displays and high-res printers, and have taught classes on the topic. I state this simply to point out that I know a bit about type. I'm also on my third e-reader. I have a K3, a Nook STR, and now a Kobo Touch, so I can easily make comparisons between these three current products.
The major typographic issue in all of these products is the low-resolution of the e-ink screen - roughly the same as a 1984-vintage dot-matrix printer - ~170dpi. This means that a 12-point character is only 28 pixels tall, and a dozen or so dots wide, which cannot support complex typography or display shaded fonts with any visual accuracy at all. For example, a stroke in any character on a Kobo screen is going have a range of 1- to 4-pixels in width, not the 50 or so that would be available for printing on any inexpensive ink-jet or laser printer.
To support my reading habit (average 2-3 novels/week), I use specific settings to make the type suitable for fast reading. When I started looking for typefaces for the Kobo, these are the criteria I used:
This image shows the terminology, and is a perfect example of a typeface that will work badly at 8- to 10-point on a KT screen, for all the reasons below.
- Serif fonts only, San-serif type is rarely used in publishing, because it is not as readable - the serifs contribute a lot to your ability to distinguish between similar characters.
- The serifs cannot be elegant, tapered, pointy, or depend on smooth fillets into the character body. A low-res display cannot display curved, narrow, or tapered serifs, as there are not enough pixels, and rendering commonly errs on serifs for this reason.
- Must be readable at 9- or 10- point size. My eyes are good (with contact lenses), and I want as many lines on a screen as possible, to minimize page-turns.
- Medium stroke width. A one- or two-pixel stroke nearly disappears on the KT screen. For a perfect example, look at the page numbers at the bottom of any screen of a book - that's single-pixel stroke width = impossible to read. To stand out on the screen, the strokes need to be in the 3-4 pixel-width range. While I have no trouble reading small type, the combination of old eyes, contact lenses, and reading glasses reduces visual contrast, so I want a slightly-bolded font.
- Consistent and constant stroke width. Variable stroke width, as in the example, appears blotchy if you don't have enough dots, and this also tends to create dropouts, where there are visible "gaps" in the characters where the width drops to a single pixel. Classical fonts were designed to look great on paper by shading to emphasize letterform shapes, and display poorly at low resolution.
- Rounded characters, with "fat" ovals. A low-res screen cannot show fine gradations in shape, so a rounded body shape displays much better than a condensed font, and oblong shapes turn into flat-sided ovals.
- Tall X-height. The body of lower-case letters should be 65-75% of the cap height for low-res display. This simply makes the characters more easily distinguishable, and speeds recognition. The example is maybe 55% X-height.
- Moderate descender and ascender height vs.cap height. Too-tall characters reduce to permissible line spacing.
So I started by selecting a few typefaces from those supplied with my Mac and with MS-Office on the Mac, but discovered that the selection of TTF and OTF fonts was pretty limited. I could convert from other formats into OTF, but that's more work than I'm willing to invest at the moment.
I wound up going to Google, for the web page fonts they offer, which were specifically designed for low-res display.
So (finally) here's what serif fonts are in use on my KT at the moment:
- First, kudos to the Kobo team for the new-with-1.9.5 Rockwell font. It meets all of my criteria, is quite readable at 8- to 10-point sizes, and is very comfortable for extensive reading. If I could pick only one serif font for the KT, it would be Rockwell. It's not pretty, but is very functional.
- I added Minion Pro from my Mac. It's not ideal, as it is a bit light in smaller sizes, but nice for 11- or 12-point reading.
- From Google (
http://www.google.com/webfonts/) I loaded Arvo, Crimson Text, Kameron, and Kreon. I keep switching, but i'm currently using Arvo, as a slightly less-dense and less-dark choice than Rockwell.
- Kobos Amasis, Delima, and Georgia do not work well at smaller sizes. I find them unsuitable for my purposes.
- Text ghosting remains a significant issue on the KT, but at least 1.9.5 delivered a workaround for the problem.
So that's that - if anyone else has similar needs and finds typefaces that work well at small sizes on the Kobo, chip in.