>>3656986>What makes me wonder about the gui is how I set the dpi. It lets me choose ppi (maximum of 600) and the resolution slider just changes the image size. Am I stupid?The ppi you're choosing (the one with maximum option that says 600 - Typesetter) has no effect on the image resolution. It's only used to calculate the maximum print size.
That's why you see the print size changing while you're moving the resolution slider (and also the file size). The resolution slider is the one actually controlling the scanning resolution. It must have a dpi value next to it, but if it doesn't, all the way to the red is 7200dpi, orange (start of red) is 3600dpi, yellow is 2400dpi.
Can't you see the value next to the slider?