> While there maybe some merit to your comments about dust in the air masking
> flaws in the slide being projected, I had the actual surface texture of the
> projection screen in mind as well as the actual viewing distance independent
> of any dust.
Haven't been following this thread all that closely so this may have
been covered. But what lens are you using for your projections? If it is
a lens supplied with most projectors the poor quality might be a masking
factor. The difference between one of these lenses and a Buhl or similar
projection lens is pretty substantial.