Comparing Carta and Kaleido E Ink tech

April 15, 2024

Ever since I got my first Kobo e-reader, I have been keeping up-to-date with the latest e-ink devices and technologies. In fact, a totally embarrassing fact is that I probably have spent far too much money on various Kobo devices and too little time reading on them.

Oh well, it’s something I’m trying to rectify. I happen to have plenty of Brandon Sanderson books to read, as well as a selection of Warhammer books I previously bought from Black Library. I also still need to finish The Hitchhiker’s Guide to the Galaxy omnibus, the first e-book I purchased, and, regrettably, never finished.

As a technology nerd, I have been really enjoying using my Kobo Libra 2: it is easily my favorite Kobo device to date. Previously, I’ve had a few older models, too, all of which I’ve been able to give new owners. I was wondering what would be next, as there were rumblings about Rakuten releasing new color e-ink devices, and that sounded cool.

PocketBook InkPad

After doing some research into various other brands, I stumbled upon PocketBook. I looked at the various devices on offer and eventually purchased a PocketBook InkPad Color 3, which sports a dual-layer approach to coloring in the form of the so-called Kaleido screen. It was this review that convinced me to pull the trigger.

I have a few digital comics, various programming books and a few ebooks that I always had to sideload onto my Kobo. All of these are more fun to read on the PocketBook. I also love that you can set up KOReader as first-class reader on the PocketBook device, unlike on Kobo where you are reliant on the NickelMenu mod.

Reading a book about async Swift on the InkPad. This device, at 7.8 inches, has a good screen for reading and small comics, but I still think my Libra has the perfect sized screen with 7 inches.
Reading a book about async Swift on the InkPad. This device, at 7.8 inches, has a good screen for reading and small comics, but I still think my Libra has the perfect sized screen with 7 inches.

The PocketBook devices are easy to customize, and armed with KOReader reading on this device is an actual delight. The built-in reader is pretty mediocre with only few customization options, unfortunately. The OS is very tweakable, though, and doesn’t send all of your data to the cloud. Good news for us privacy conscious folk!

I’m not sure if I’ll be keeping the PocketBook, given the new Kobo lineup is a more close match to what I’m looking for in a device, but it has provided me a good early glance at what to expect from these new screens.

Frankly, it’s a bit of a mixed bag, to be honest: the screens are darker and there’s an apparent grain due to the way these screens work.

Examining Kaleido 3

And then a couple of days ago, Kobo revealed their new Kobo Clara Color and Kobo Libra Color devices, which are going to be using the same Kaleido technology. To be fair: this is awesome technology.

These screens are significantly darker compared to their older Carta siblings. Here’s a macro shot of my PocketBook’s similar screen that shows the persistent RGB layer which can be found below the “ink” layer:

The resolution of the color layer is 150 DPI. The resolution of the ink layer is twice that, which allows it to block individual red, green or blue pixels on the color layer, thus simulating color. If all colors are allowed to come through, the color is “white”.
The resolution of the color layer is 150 DPI. The resolution of the ink layer is twice that, which allows it to block individual red, green or blue pixels on the color layer, thus simulating color. If all colors are allowed to come through, the color is “white”.

It’s subtle from afar, but when it comes to text-only books I strictly prefer the Carta screens, if only because they are lighter and don’t have this “grainy” look which is caused by the color layer. For comparison, this is macro shot of the Carta screen, the surface of which definitely looks a little bit more like paper:

The Carta 1200 display on my Kobo Libra 2. Please note that due to zoom level of the image typography here looks less sharp, which is not representative of the device. Please note the surface, though, which looks very paperlike.
The Carta 1200 display on my Kobo Libra 2. Please note that due to zoom level of the image typography here looks less sharp, which is not representative of the device. Please note the surface, though, which looks very paperlike.

I suspect that the new Kobo color devices will look the same, which is definitely going to be a little bit of a disappointment for me. The colors using this display technology certainly look okay, but they are still quite pastel-like, and the trade-off is worse text rendering for normal books.

I’m certainly going to be hanging on to my Libra 2, that’s for sure, as I personally find the Carta display a bit nicer to read on.

Curiously, Kobo will be offering a cheaper black and white variant of their smaller device, a Kobo Clara BW. This will be available alongside the Kobo Clara Color variant, which I think is a good move.

I hope they consider a similar Libra model with a Carta display in the future, with equivalent hardware upgrades internally. The new Libra Color seems to have received more memory and a faster processor, too. A welcome upgrade.

Tagged as: Reading Hardware