The scanner location should have a controlled ambient light situation.
The light scenarios should avoid direct sunlight or spotlight from light
beams. Also, light sources that cause sharp shadows on the document
on the book cradles or high levels of ambient light could negatively
influence the scan result.
The scanner is an open system with a built-in high quality light source.
Open system means that the ambient light is added to the light seen by the
camera. Summary of a recommended location for a scanner: The location
is not exposed to daylight. It is evenly illuminated from the ceiling with
fluorescent lamps with electronic ballasts. The light intensity measured on
the book cradles should be between 300 and 800 lux. The light should not
cause any shadows; therefore, the variation of the intensity across the
scan area should be kept below 20%. Fluorescent lamps, powered by
nonelectronic ballasts, can produce a flicker twice the frequency of the
main power supply (100Hz or 120Hz). The same applies to certain simple
LED luminaires. If the intensity of this light becomes too high, vertical
stripes will be visible on the scan. Direct sunlight will result in overexposed
images. Sunlight can also produce distinct shadows. Light beams from
spotlights will also change the color of the scans. The scanner has an
integrated “White Balance” function. This function will compensate
ambient light influences. A “White Balance” calibration is recommended
when the light scenario has changed.
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