Dichroic Safelights

The majority of laboratories handling color positive films use a filter in their printing and processing areas which has a bandwidth that overlaps areas of high emulsion sensitivity; therefore, the light intensity must be kept low. Some laboratories have tried sodium vapor lamps, with filters to absorb unwanted side radiation. These provide high-intensity monochromatic light at wavelengths where the film has low light sensitivity. Unfortunately, this type of lamp has a high initial cost and a relatively high maintenance cost, making it impractical. A special fixture using a dichroic filter and a prefocused lamp has been designed. The output of this lamp successfully matches the filtered sodium vapor lamp and provides the illumination in a more efficient method requiring lower initial cost and considerably lower maintenance expense.

Print ISSN

0361-4573

Published

1967-01

Content type

Original Research

DOI

10.5594/J09206