Insane.
Methinks a lot of the replies on here are from people who have never used a HD44780 LCD display. Two of mine don't have back-lights so the brightness is entirely irrelevant (black on green work without and some didn't bother with back-lights), but they have contrast pots.
Hehe, just scanned floresta's QR code, he most certainly does know what he's talking about.........
When changing brightness MUCH, it also helps to adjust contrast -- for pretty much the same reason. That being that the pupil of the human eye changes with light level. You don't HAVE to but it can make a difference for the better. Of course wtf do I know?
I always thought the contrast setting was more of an LCD bias adjustment. It seems to be more relevant to viewing angle than ambient light conditions. E.g., I've never adjusted one based on presence/absence of backlight or ambient light, but in my car, my first CD player was unreadable from over 100 degrees above and below on the same contrast setting. Buuuut, I'm far from an expert on this topic.
Thanks guys