ArtixScan 4000t, SF 5.5 slow using other lightness

[waltavista]

i try to adjust the lightness (brighter) of the scanner (options -> special). the scanner works very slow in this mode. i think it takes the double time.
why?

thank you.

walter.

[LSI_Kratzenstein]

If you set the lightness brighter, then the scanner use the light on each row longer, to get brighter data. That slow down the whole process. The lamp brightness don't bright up the lamp directly.

kind regards