Dunno, after you know what it is it looks obvious, but prior to that it looked like a semi-solid block that only got worse if you zoomed in. I could confidently make out one radical between the two. Maybe I just need to work on my kanji reading skills.
The second one is quite clear, even at normal zoom. I might not have been able to read the first one at first (at first glance it looks vaguely like η¨ to me, but with another column somehow :P ), but at least I can see the ζ radical there, which would make it easy enough to find the entire word in a dictionary. :) But yeah, it is pretty small...