> Maybe I'm just an old grouch.
Yes.
Reading on iPad is great.
Yes.
Reading on iPad is great.
I think tablets are a decent secondary substitute for print-form only for publications like this with figures and images, and where the activity is more browsing rather than linear.
For general reading (eg fiction) I think print is optimal, followed by e-ink with normal tablets considerably down the list.
The ease of access to a library bumps up the utility of the ereader and tablet considerably.
Interesting that my impression is more or less the opposite: I can read on a tablet all right, but leafing through is annoying and switching back and forth between three or four places in a big (thousand-page) reference book is so annoying as to be nearly impossible. The first, because rendering PDF pages (understandably) takes time, and the second, because I’ve seen no bookmarks interface as seamless and convenient as leaving a loose sheet of paper or even just your finger in the necessary place—they’re all much too fiddly.
I haven't found anything better than paper for technical docs, but getting a PDF and printing the few pages I need is amazing.
E-ink is mechanical [1] so also relies on reflected light rather than being a light source.
More energy would mean more stimulation?
The eye was designed to look mainly at reflected light?
There is potential damage from consistant over stimulation?
Maybe its not a great idea to constantly shine light directly into your eyes?
Correct!
> but I have a hunch that the light hitting your eye from a direct light source is higher energy than that from a reflected light source?
Incorrect!
There's no concept of photons that have or have not been bounced, or are "direct" or "indirect". Also, you probably want to talk about intensity, not energy. Energy has to do with frequency (the color of light), intensity has to do with the amount of total light.
> More energy would mean more stimulation?
As it stands this says that blue light is more stimulating than red. Amusingly, this is true! But not in the sense that you meant it. It has to do with how our rods and cones work and how your circadian rhythm is calibrated. People use red light not to screw up their night vision so much.
Perhaps you mean more intensity? That's actually false!
Sunlight is incredibly strong. Far stronger than any artificial light you have normally.
> Maybe its not a great idea to constantly shine light directly into your eyes?
I'm sorry to say this would require the removal of your eyes.
But seriously. What matters is not "direct" or "indirect" light, which is a meaningless concept. What matters is relative contrast. E-ink feels better because the contrast in intensity between it and the background you're on is lower.
A few years ago, I wanted a photo near a window with one half on sunlight and the other half in shadows. I tried to adjust the camera, the distance, direct or indirect sunlight, the illumination inside the room to illuminate the "shadow". It was impossible, the sun is too bright compared with usual light sources. I finally gave up and faked it with gimp :) .
How many times researchers go find article PDF on notnamed site, then print it for reading and annotating, just as one would do with a copy from a printed journal.