I have poor vision, need 10 inch high contrast reader

[meeera]

Originally Posted by AnotherCat

I have not seen any well constructed research into environmental exposure compared to that from displays, probably because it is blindingly obvious that environmental exposure is very much greater

I see what you did there...

and, of course, is dependent on season, latitude, time of day, etc. and display. But no doubt they exist because I see estimates (e.g. by Zeiss) that exposure to blue light under an overcast sky is approximately 30 times that from a typical display.

I was just assuming that the OP practises intensive sunlight protection as well (myself, I avoid the outside, wear sunglasses 100% of the time when I am outdoors and a broad brimmed hat most of the time) - so I was giving the most conservative possible recommendation, which is a temperature-adjustable eink display.

[j.p.s]

Originally Posted by AnotherCat

Any lighting on current devices and displays is safe compared to our environmental exposure.

I have not seen any well constructed research into environmental exposure compared to that from displays, probably because it is blindingly obvious that environmental exposure is very much greater and, of course, is dependent on season, latitude, time of day, etc. and display. But no doubt they exist because I see estimates (e.g. by Zeiss) that exposure to blue light under an overcast sky is approximately 30 times that from a typical display.

So, taking that as an example, one would have to read on a typical display for approximately 30 hours to have the same exposure as one hour exposed to an overcast sky. Furthermore, under natural light one is also exposed to the fact that the blue light extends strongly into the ultraviolet and while the jury is out somewhat on what extent UV plays in degeneration, cataracts, pterygium, etc. there is little doubt there is some danger because we know the negative effects of UV on skin (degeneration, solar keratosis, various cancers, and other lesions).

So, if one applies the sensibility test, exposure to blue light from devices is not significant compared to our other exposures to it and those who are concerned about blue light from their device causing eye disease but are fans of E Ink because it enables them to read outside seem to be unaware of the facts.

Those are all good points, especially regarding UV and blue outside versus blue inside. But pupil dilation is likely significantly more inside, so a big chunk of that 30:1 ratio goes away. If the color temperature of the display is significantly higher than an overcast sky, the blue brightness ratio comes down even more, and might even go below 1. So I don't think the 30 hours inside for every hour outside is a good estimate (for blue light).

[Neru]

I just wanted to recommend Note Lite if you wont be taking notes. Its cheaper and it does not have a Wacom layer so I think that it should have better contrast.

[AnotherCat]

Originally Posted by j.p.s

...But pupil dilation is likely significantly more inside, so a big chunk of that 30:1 ratio goes away. If the color temperature of the display is significantly higher than an overcast sky, the blue brightness ratio comes down even more, and might even go below 1. So I don't think the 30 hours inside for every hour outside is a good estimate (for blue light).

The 30 times exposure estimate was referring to the exposure of the eye, not a comparison of the environment intensity. Also, just in case of any other misunderstanding, when I referred to latitude, etc. that was not inferring that the color temperature of the sky changed with it but that the intensity of the light radiation varies with it.

If pupil dilation is more then it means that the intensity of the light radiation is less i.e. the light source is weaker, so the iris manages the light entering the eye accordingly; one can assume under normal indoor and exterior lighting conditions the iris manages the light so that the intensity entering the lens is approximately constant (in the same way as a camera works if speed is fixed and exposure controlled by the diaphragm alone).

It is very unlikely that the color temperature of the display is higher than that of the sky. Because:

The color displays that we are ever likely to employ use the sRGB Color Space and the sRGB White Point is 6500Kelvin and most displays will be set around that when delivered. As most displays are used inside it is more likely that if the user were to reset the color temperature it will be set warmer (say towards 5500Kelvin) than cooler (Note that when talking about displays "warmer" is normally taken to mean towards the red, and "cooler" meaning towards the blue, whereas in fact, in black body color temperature terms, blue is "hotter" which can lead to some confusion). If a display is used outside it may be set at a higher color temperature (say towards 7500Kelvin). All that assuming the user actually enters the display's setup and manually changes the color temperature, something the vast majority of users never do unless the display is on a simple device that just gives a "normal" and a "warm" checkbox selection (rather than the incremental adjustment one has on a monitor, say) in which case they can never set a color temperature greater than around 6500Kelvin. Some months ago I actually gathered up all the tablets and phones around here and with their displays set to normal (i.e. not to "warm" or "blue filtered") they were all almost exactly 6500Kelvin. I also checked 2 monitors and 2 notebooks with the same result (those all were still at those factory settings as they are used for photography).

The color temperature of an overcast sky (as any well versed photographer will know) varies between 6500-7500Kelvin and that of a blue sky may exceed 9000Kelvin. So, it can be easily seen that it is very unlikely that displays in in typical uses will have a color temperature higher than that of the external environment.

[frankrec]

Originally Posted by Neru

I just wanted to recommend Note Lite if you wont be taking notes. Its cheaper and it does not have a Wacom layer so I think that it should have better contrast.

The Note Lite sounds exactly what I need. Thanks