Is there any empirical data on the comparative contrast between the words and the screen background on the various readers? I've read that the new Sony Reader has better contrast than the older model, but how much better? Is it possible to compare the displays with a densitometer or something? I'd be curious to how the various devices fare in this test. Does anyone have solid information on which (ePaper) display has the best contrast? I have a Sony Reader PRS-500, and as much as I like it, I'd like it a lot more if the background were closer to actual white paper in appearance.

Jim

Is there any empirical data on the comparative contrast between the words and the screen background on the various readers? I've read that the new Sony Reader has better contrast than the older model, but how much better? Is it possible to compare the displays with a densitometer or something? I'd be curious to how the various devices fare in this test. Does anyone have solid information on which (ePaper) display has the best contrast? I have a Sony Reader PRS-500, and as much as I like it, I'd like it a lot more if the background were closer to actual white paper in appearance.

Jim

Nobody's done a test like this.

However, may I point out that the older eInk devices all pretty much use the same older display and the newer ones all use the, newer, Vizplex display. As both these are from the same OEM source, you're not going to get much (shouldn't have *ANY*) difference between retail sources for Vizplex-based eInk readers. And I'm quite positive I read *somewhere* that PVI is working on creating a newer generation of eInk displays (available by late 2008/early 2009) that will be even closer to a white paper background - although I have both the PRS500 and the Cybook Gen3 and I'd equate the PRS500 to the gray of a really crappy Trade Paperback text while the Cybook is closer to the color of a good-quality newspaper page.

Derek

The older screens reflect about 35% of ambient light, the VizPlex screens about 40%. ie the VizPlex screens appear about 15% "brighter" than the older ones. It may not sound much, but it's a very definite visual improvement.

There is an interesting post over on the iRex blog (http://i-to-i.irexnet.com/2007/11/09/what-makes-our-electronic-paper-displays-different/) which discusses how the iLiad is different from other eink screens, but promises a comparison of the current iLiad screen, and a prototype VizPlex iLiad screen, so there might be some good comapariative data soon.

There is an interesting post over on the iRex blog (http://i-to-i.irexnet.com/2007/11/09/what-makes-our-electronic-paper-displays-different/) which discusses how the iLiad is different from other eink screens, but promises a comparison of the current iLiad screen, and a prototype VizPlex iLiad screen, so there might be some good comapariative data soon.

Visually, I'd put the iLiad screen on a par with the VizPlex screens. The iLiad (or at least my iLiad) has a dramatically better screen than my older Sony PRS500.

I'm enjoying reading with my 505 more then I did with my 500. That is due to the better contrast the Vizplex screen gives. It's not due to any other changes made in the 505 vs the 500. I was very well used to how the 500 handled and didn't have a problem with it. Vizplex screen don't fade in sunlight and they don't need as mch light to read with.

The older screens reflect about 35% of ambient light, the VizPlex screens about 40%. ie the VizPlex screens appear about 15% "brighter" than the older ones. It may not sound much, but it's a very definite visual improvement.

Brightness and contrast are two different things. I do not dispute you view that it is a visual improvement but interestingly the specs for e-ink original said the contrast was 8:1 and for the visiplex is is 7:1 so maybe the black isn't as black or something. iLiad is seen by people to be as good with the old screen so there may be more differences that we think that influences this.

Dale

On the 505 the blacks are definitely darker, in addition to the background being lighter.

On the 505 the blacks are definitely darker, in addition to the background being lighter.

Interesting. Maybe the original e-Ink specs lied and the revision was only to make the spec more accurate. I wonder how we can measure the contrast ratio?

Dale

There is more to it, than just specs. iRex seems to have managed a technology, which allows for waveform specifically made for certain eink batches. Those seem to result in much better contrats than standard waveforms.

Then, there seems to be some degredation of the eink screen after a few weeks of usage.

And there seem do be differences in contrast depending on the eink batch.

And there could be production steps which influence the contrast.