Print Phd thesis in A4 or A5? I would like to ask those in Academia who supervise PhD students and get to read their Phd theses. When checking on previous theses submitted to the library, I found some printed not in the more common A4, but A5 format, half the size of A4.

I was wondering whether is is more comfortable for supervisors to read a thesis of roughly 200 pages (just counting the main matter) in A4 or A5 format? My thesis would contain some "normal-sized" tables and figures.
Firstly, just checking the library is not enough — there might be restrictions on the format and only the relevant office can tell you what those restrictions are (if any).

Secondly, if you find out that you do have a choice (between A4 and A5 paper, for example), the natural thing to do would be to ask would be your supervisor in what format they would like to read your thesis.

(After submitting several printed copies of the thesis for review, you may get some of them back after your thesis defence, which you can submit to the library.)