Paper labs use reflectance spectrophotometers with an integrating sphere, a xenon or filtered lamp and an adjustable UV filter for setting the ultraviolet content. The unit records reflectance in 10 or 20 nm steps from about 400 to 700 nm, then calculates R457, CIELAB values, whiteness and opacity from that curve. Bench instruments are checked against working standards every shift and restandardized against certified ones on a schedule.
Spectro is down for its UV check, so run the reel samples on the backup unit and flag them in the log.
Read every sample with the machine direction pointing the same way; mixed orientation adds scatter to trend charts.
Also heard as
- spectro
Related terms
Integrating sphere
Hollow sphere lined with a highly reflective matte white that bathes a sample in diffuse light from all directions.
d/0 geometry
Measurement setup with diffuse illumination of the sample and viewing perpendicular to its surface.
UV calibration
Setting an instrument's ultraviolet content so fluorescent samples read as they would under the specified illuminant.
Reference standard
Certified material with assigned reflectance values that transfers a measurement scale to a working instrument.
Cal tile
Lab shorthand for the white or colored ceramic tile used to check or standardize an instrument each shift.