The roll up mechanisms will not be durable enough. They can't be, unless aided by gravity. Believe me I've tried. Having built roll-top doors for sailboat furniture for a long time, I've built numerous prototypes with all materials available, and so have many collegues of mine.
The main culprit in this application is the "squaring effect". If a user forces one hand up or down in the same plane there will be destroying forces. The only corrective is setting the display between aligning tracks, which totally defeats the roll in practicality.
Then there is the stress induced stop lock at the end of the roll when you get to the end of the motion. I give it no more than 100 roll-in roll-outs before it breaks. Unless the motion is motorized it won't work with careless people, meaning most everybody.
Then there is plastic aging provoking tearouts unless it is bonded to a canvas. (kevlar or natural fibre)
Then an unrolled sheet of plastic has a curvature effect that will be totally annoying. Even with the shape memory training that some materials have, over time they will bend.
I could go on and on...
To the subject of contrasts and lighting. After using eink for a while the only beef I have is making it brighter than the surroundings. Whatever lighting scheme you try, the background always pops out compared to the display itself, even your hands seem brighter(I'm thinking of wearing black gloves
). That makes it tiring after some time, specially if you have a burned spot in the focus center of your retina. One solution is having only the screen available to see. Reading in the dark with a tiny spotlight works best. Or total sunshine!
Eink definitely needs new inks!