Automated Uv Control; Retroviewer - HunterLab LabScan XE User Manual

To change the area viewed, remove the magnetic sample port insert by twisting it until it pops up.
Replace it with a port insert that has an opening slightly larger than the illuminated area. The white
mark should be aligned to the front of the instrument. Standardize the instrument. The instrument
automatically detects whether you have the proper port plate installed.
Change to the standard 1.75-inch area and standardize before performing any instrument checks, such as
reading the green tile.
Note: When the zoom lens is moving to a new position, there is a slight delay and the "In progress"
light flashes.

Automated UV Control

A pair of ultraviolet (UV) exclusion filters is available as an option to the LabScan XE. The filter pair
includes a 380-nm UV control filter and a 420-nm UV cutoff filter. The 420-nm UV filter may be
controlled separately, placed in or out of the light path, or the filters may be controlled together using the
UV control options of "Nominal" and "Calibrated." These filter positions are controlled through your
software. The instrument should be standardized in the chosen configuration before measurements are
made. A white fluorescent standard is used in the UV control and checking process.
For the measurement of optical brighteners or UV-induced fluorescence, the calibration and control of
the source UV energy is important. UV-induced fluorescence can vary based on the geometry of the
instrument used, the spectral properties of the simulated source (usually D65), the condition of the
instrument's lamp, and the fluorescent characteristics of the sample. Using the variable UV filter
available on the LabScan XE, the proper ratio of the energy in the UV region of the electromagnetic
spectrum to that in the visible region of the spectrum can be achieved and maintained. This improves
the agreement of the illumination between different instruments.
Transfer standards marked with known values are used to set the correct illumination conditions. These
standards are stable Spectralon traceable to a four-step cotton white scale from Hohensteiner Institute in
Germany. Their use keeps illumination constant as a lamp ages or after a lamp change.
Note: It is important to know what type of fluorescence is involved for the samples being measured.
Some materials fluoresce due to excitation by visible rather than ultraviolet wavelengths. The UV-
absorbing filter does not eliminate this type of fluorescence.
Note: When the UV filter is moving to a new position, there is a slight delay and the "In progress"
light flashes.

Retroviewer

The retroviewer consists of five lamps, a motorized mirror, and a retroscope. It is used to accurately
position specimens at the sample port prior to measurement. When the retroviewer is turned on by
pressing the retroviewer button, the mirror is inserted into the optical path and the lamps are turned on to
illuminate the specimen, which can be viewed through the retroscope. Focus the retroscope by grasping
and turning it gently. When the retroscope is screwed all the way in (clockwise), the position is set for a
1.75-inch area. The area of the sample seen in the scope is what will be measured. The lamps are then
turned off and the mirror automatically retracted prior to taking the measurement.
The retroviewer has two modes of operation:
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Introduction to Your LabScan XE System 2-5