On my 8700 you could brighten the screen (even if it was otherwise set to 100% brightness) by holding down the on/off button for a second. When I do that with my Curve's end-call/on-off button, the button either acts like an escape key or, if I hold the button down much longer, it (not surprisingly) turns the unit off.
When I reset the Curve, and the hour-glass routine appears, the screen brightens at one point considerably over the level of brightness that its settles down to (again, even with the brightness setting in Screen/Keyboard options set to 100%), so I know there's a way to get the screen brighter. What's the button for this purpose if the end-call/on-off button doesn't do the trick?
There isn't. The 8100, 8300 and 8800 have automatic backlighting that can be selectively enabled or disabled. The hard key (like on the 8700) to do this no longer exists. Unfortunately, the brightness level set in Options > Screen/Keyboard remains constant.
Yes it does. What I meant in my post is that the 8100, 8300 and 8800 are all lacking the old "power" button that would accomplish that on the 8700. The only button now is the mute button, which, when held will put the device into standby.