Scan brightness/contrat adjustment

In the graphic tools in the MATE menu, there is one entry for scan (not sure about the name in English) and it works. In the preferences, it is possible to select the resolution in dpi and adjust brightness and contrast.

If one is adjusting the brightness and contrast there, one needs to scan the document again, it is rather slow (about 10 seconds), and if the outcome is not good enough, one needs to try again, so it can take really long.

Is there a way to do a scan, see the outcome, then as one adjusts the brightness/contrast have immediately a preview of what it would look like, then when one is happy with some settings, do the scan again?

I am asking because my aunt is used to that feature in windows and is rather frustrated not to have it in Trisquel.