We want to do a photo album which we intend to publish in print and also electronically on iPad and Android tablets.
If we want to do a single output (PDF etc.) for all media, which would be the best "average" proportion ratios in order to fill up the screen space as much as it is possible on the most tablets?
Please read the word 'most' above as in 'market share' not as in 'number of tablet models'.
Also, because the most photos come from a dSLR (3:2 ratio) with few text(s) around them, I think that the aspect ratio should be rather closer than farther to 3:2.
Another consideration is the print size/ratio: It shouldn't be an 'odd' one, even if it will be ok for the tablets.
The album will be done in InDesign, if it matters.