A study was conducted in which the cause of flow pattern, a repetitive mottle-like defect, was investigated. Results obtained indicate that vacuum pressure fluctuations occur at the start of coating by the vacuum flow port that are 367% greater than at the center of coating. These fluctuations decay in time during the period of flow pattern occurrence, and range in frequency from 0 to .10 mm-1. These pressure fluctuations correlate to flow pattern density fluctuation frequencies of the same range. Additionally, it was seen that the decay rate of the ME side of the vacuum chamber was three times the rate of the UME side. No significant pressure fluctuation phenomena was observed by the end seals of the vacuum chamber.

Publication Date


Document Type


Student Type


Degree Name

Imaging Science (BS)

Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Serafino Cardinali


Physical copy is available from RIT's Wallace Library at TR395 .F48


RIT – Main Campus