Here are two posters from the same conference, photographed at roughly the same distance. (Identifying information has been slightly pixelated.)
This poster is not using its available space well. The board is half empty. But although I cannot read virtually anything at this distance except maybe the headings and title, I can see that there are bar graphs on the poster. I can see blocks of colour.
This poster is about the same size the one above, and suffers from not using its available space well. But it’s suffering in so many more ways. The content of the poster has faded away in the distance like disappearing into a fog. There are no blocks of colour; everything has turned to gray. You can make out that there are columns of text, but you can’t make out anything about the figures.
I am not sure either of these posters would pass the “arm’s length” test. But while both posters are far from ideal, the top one succeeds in that at least at these long distances, you can make out something that is recognizable.
The smaller and further away you can get from your poster and recognize something on it, the more successful your poster is likely to be. Even if that is just blocks of colour.
On the Nature of Things
2 weeks ago