Bio-Rad Model 680 Microplate Reader Accessories - Manual (Page 35)

Chapter 4. Protocols
27
Figure 17. Measurement wavelength settings in the Protocol dialog box
(Benchmark Plus version shown).
For the Benchmark Plus, you can adjust the monochrometer by clicking on the up-
down arrows next to each filter field, or you can enter values from 340 to 800 nm
directly in the fields.
For microplate readers other than the Benchmark Plus, the available filters are listed
in the pulldown menus. (See page 11 for instructions on how to set the filter
wavelengths for your microplate reader.)
Single and Dual Wavelength Readings
If you select the Single button, one measurement wavelength will be used for reading
each well.
If you select the Dual option, you can also select a reference wavelength. The
reference wavelength will not capture any data, but will provide a baseline reading
for the wells in your microplate.
If you perform a reference reading, you can subtract that reading from the
measurement reading by selecting Subtract from the pulldown menu. Alternatively,
you can divide the measurement reading by the reference reading by selecting Ratio
from the pulldown menu.
Note that subtracted dual wavelength readings will generate data measured in ODs,
while ratioed dual wavelength readings will report a simple ratio
(measurement/reference) with no units.