A client has just asked about the on-screen legibility of
Verdana vs. Arial at small sizes on platforms where the text
will be aliased, so I thought I'd quickly mock it up in html/css
to see the result. Most modern browsers have anti-aliasing capability and so text will render with smooth edges. To give an idea of how copy set in 10pt renders for users browsing without an anti-aliasing engine, here's a screenshot:
Verdana was designed to be read at small sizes, and its wide proportions make it a good choice for body copy, but is it more legible? Both the Verdana and Trebuchet bold text stand out much more than the bold text set in Arial and Arial certainly looks smaller in comparison. Type choice will always be a personal preference, but in terms of legibility at small sizes, I think Verdana is a clear winner over Arial, especially if bold headings are to feature within the typographic hierarchy.