MITSUBISHI ELECTRIC DV1248ST - Manual (Page 50)

Image 1 is the original scanned image, while in Image 2 the threshold value is
changed into 56. This means that pixels in the image with brightness level below
56 will all be cut into black, and those with brightness level above 56 are all turned
into white. Therefore, you will find that by setting a lower threshold value, some
details are lost in the new image. However, if there are many unwanted dots in an
image, you can eliminate them.
When you have finished with the threshold adjustment, you can click OK to
confirm, or click Cancel to abort and exit the dialog box. Otherwise, you can click
Reset button and the settings will return to the default 128.
Invert button
You can click the Invert button to get an inverted or negative image:
Mirror button
You can click the Mirror button to get a mirror reflection effect on the
original as if you were viewing the image in a mirror:
Original image Image after Invert
is applied
Original image Image after Mirror
is applied