Can't seem to set the brightness with GdTWAIN

[procreator]

I can't seem to adjust brightness or contrast using GdTWAIN (GdPicture Pro package). I am trying to interface with a HP Scanjet G3010.

These are the lines of code take from the demo code, with the exception that I replaced the scroll bar value with a constant.

Code: Select all

Imaging1.TwainSetAutoBrightness (False)
Imaging1.TwainSetCurrentBrightness (-100)


If I return the available brightness values, I get an array ranging in values from -1000 to 1000.

Any ideas?

Thanks!

[MIKES]

Are you scanning in Black/White or Grayscale.
Just tested mine and Brightness has no effect when scanning Black/White.

Are you checking for an Error? Though I have not seen setting brightness fail.

Code: Select all

If Not Imaging1.TwainSetCurrentBrightness(Bright_Value) Then
      Result = CheckForLastError("Failure Setting Brightness: " & Bright_Value)
End If

Is (-100) enough to notice? Try the extremes 1000 and -1000

[procreator]

I installed the full driver package that came with thte scanner, and I no longer get an error code when I try to change the brightness. However, the image itself doesn't seem to be affected when I change.

Any ideas? If this functionality doesn't work on this model of scanner, is there another with which it will work?

Thanks!

[procreator]

BTW - I am scanning in grayscale, and have tried brightness settings ranging from -1000 to 1000.

[MIKES]

I do not have any more ideas, perhaps Loic does.

Are you familiar with the twack_32 application in the Twain Developers TookKit on www.twain.org ?

I have found it useful to check getting/setting a scanners capabilities without having to program for it.

[procreator]

I got the problem fixed. Apparently the scanner driver didn't install correctly the first time. Unplugging the scanner, then plugging it in resolved the problem.

Thanks for all your help!