Dear all,
I`m dealing with a photosensitive film (non commercial PR) deposited on
a reflecting substrate.
I'm using contact photolithography (Hg lamp) to print the film. The film
is patternable but problems arise when the pattern to be transferred is
an array of squares. In this case I observe phenomena due to light
diffraction (Fresnel type). All the literature I found `till now discuss
the interference phenomena when using shadow printing (in this case
Fraunhofer theory applies), but no information are given for contact
printing.
Can you suggest me some good readings about it?

Thanks alex