I work as a photographer/designer in a hospital. If it weren't for ppt, there'd still be a lot more of us.... but then again 3/4 our time would be spent making copy slides zzzzzzzzzzzzzzzzzzzz (ack - I just realized I cannot for the life of me remember how to make a blue slide with film.... I used to make so many....)

I recently saw some (old I think) research paper about slide shows and information retention. Someone actually made slides in all sorts of colors raging from traditional white text on blue to some rather horrendous and hard to read color combos with serif, san serif and script text styles. It came as no surprise that script wasn't so great, but the color combo that the person determined worked best was noxious.... I seem to remember it was burgundy text on an orange background..... sounds more likely to make your eyes bleed than to help you remember.