The HSL/ULO (formerly HSE/NPL) Phase Shift Test Slide was developed to provide a reproducible phase object to check microscope system performance prior to counting asbestos fiber samples.
Phase Shift Test Slides consist of a conventional glass microscope slide with seven sets of 20 parallel lines in each band. Each band progressively decreases the line width and dept from 1.1um (Band 1) to 0.25um (Band 7).
During manufacture, phase contrast test slides are evaluated and grouped into one of three categories:
- Band 4 Slides (Red Certificate) - Band 4 fully visible / Band 5 partially visible (500x)
- Band 5 Slides (Green Certificate) - Band 5 fully visible / Band 6 partially visible (500x)
- Band 6 Slides (Yellow Certificate) - Band 6 fully visible / Band 7 partially visible (500x)
The slides that Zefon provides are Band 5 Slides (Green certificate). In the US, Band 4 slides (Red certificate) have been required until recently. Band 4 slides have proved very difficult to manufacture and are not being manufactured anymore. In response to this, NIOSH has collaborated with ULO Optics and agrees that Band 5 slides still meet the intend of US asbestos standards when used as directed by the manufacturer. Please see the Phase Shift test Slide Fact Sheet for more information.
Additional Information Available
Phase Shift Test Slide Instructions
Phase Shift Test Slide Fact Sheet