Probably more a monitor thing than anything. I got to 24.
Same here. The colors changed substantially depending on my viewing angle. The later tests looked like a gradient test pattern.
I got to 29. The entire top row looked dark. Then I sat up a bit, and half of the blocks changed color.
Sometimes I really miss my good old 21" Trinitron CRT. :\
I've not yet used an LCD that compares to it in image quality or pixel response rate, but I
don't miss its 70lbs of glass. (That is to say, I'm sure I
could get a nice IPS that would match its color and pixel response rate, if I allocated a full month's salary toward the purchase.)
Edit: Checked the specs on my monitor. 6-bit, so I guess I'm limited to 262k colors on static images. (They claim 16M with frame rate control dithering....I don't know how well that'll actually work though, at least for something like this.)
72% NTSC color gamut.
I'll have to give it a shot on my tablet. I think it uses an IPS screen.