-halftone

-halftone value

Turns on the halftone capabilities when acquiring an image.  The value will be the name of the halftone method to use.  Only TWAIN devices that support halftones can use this option.

Halftoning is an aspect of image processing where the solid parts of the image are actually a series of dots (or dithering) that simulates the solid color.  If the image doesn't have to be high-resolution, use this option for reducing the size of the image in bytes,

The value that is used is dependent on the device.  For a list of the various patterns, produce a -details log for your device, and search for the Device_Halftone_Values values.

If the value has embedded spaces, the value must be enclosed in double quotes.

Example:

twainsave -f test.bmp -halftone "Dithering Pattern 1"

The above acquires an image, and uses the "Dithering Pattern 1" halftone.  Note that the name "Dithering Pattern 1" is device dependent.  You should always inspect what the valid halftone names are for your device by producing a -details log.