User guide

Quantity One User Guide
8-12
Fig. 8-9. Options dialog box.
8.6.a Dark Subtraction Type
All CCD cameras accumulate electrons that produce a signal that is
indistinguishable from light. This “dark count” adds to the noise in your
images. In most cases, you will want to subtract this dark count from your
images.
Normal
The Normal option button selects the default dark subtraction type. In this
mode, after you acquire an image, a “dark” image of the same exposure
length will be taken, and this will be subtracted from your image.
The progress of the dark exposure will be displayed in the Exposure Status
bar following the regular image exposure.
Note: In Normal mode, a dark image is only acquired the first time you perform
a scan with particular application and exposure settings. If you perform
subsequent scans with the same settings, no dark exposure will be taken.