Quote Originally Posted by JBrunner View Post
Newton rings can form between any two surfaces that are not in complete contact with each other. J
Just an observation...the rings can also form from uneven pressure. I packed a contact printing frame with extra padding to increase the pressure and only increased the rings. Areas directly under the springs were under greater pressure. Reducing the pressure by removing some of the extra packing got rid of the rings.

Vaughn

ic-racer -- I have a couple B&S contact printing frames...good quality!