>a control panel

That control panel was really great! Particularly for scanning, it was nice to be able to adjust some of the color curves slightly to correct the scanned image.

However, one thing I REALLY used that control panel for was greyscale images, you could adjust the curve so that things that were barely legible in the image suddenly popped way out. Almost like that trick of rubbing a pencil across a blank page to reveal what someone wrote on the page above it. Or smaller adjustments just to make a greyscale more uniform.

That was really one of xv's superpowers.