The Effect on Screen Illumination of Bubbles, Seeds and Striations in the Bulbs of Projection Lamps

In Blowing glass bulbs for projection lamps, there occasionally occurs in the glass small bubbles or slight ridges on the glass known as “striations.” Sometimes, a small mold mark is left in the glass. It seems to be impossible to entirely eliminate all of these little flaws. On several occasions, complaints have been received that blisters in lamp bulbs have been the cause of poor screen illumination. All of these complaints have been indefinite, and no specific data seemed to be available on the subject. In order to determine definitely whether or not there was any such detrimental effect, the authors, conducted a series of tests on lamps of various sizes and in different types of projectors.

Print ISSN

0096-6460

Published

1926-05

Content type

Original Research

DOI

10.5594/J10287