Yeah, I was noticing that myself. I actually have granite in one of my forts, and a bunch of granite doors near a bunch of gabbro doors. So I need to figure out a solution for that too.
[Some time later]
So, yeah, granite has a black background color, where most other stones have a light gray background color. However, doors' colors are also determined weirdly. Doors are using, for the door's FG:BG:FGbright, the stone's color's BG:FG:0, with the exception that if FG and BG are the same color, the FG color's brightness becomes 0 instead of 1.
So I was thinking I could just change granite to be the same color as the other medium-gray stones, but then I realized I couldn't remember actually SEEING any in the past several months... I could've sworn that there were medium-brightness grey stones that weren't dark and weren't light, but I couldn't find any in-game or in the raws except, of course, for bizarre granite. Since I distinctly remembered the 2d version making a distinction between the three kinds of stones, I ended up checking the 2d version. It turns out that the colors of stones apparently changed from the 2d to the 3d versions.
Obsidian, onyx, and jet were 0:0:1 in the 2d version. Dark stones are 0:7:1 now.
Limestone, marble, and moonstone were 7:0:1 in the 2d version. Light stones are 7:7:1 now.
Other light stones were 7:7:1 (talc, pumice, dolomite, chalk, flint),
Gray stones were 0:7:1,
and there were presumably brown stones that were 6:7:0, the same as now.
0:7:1, in the 2d version, was the color of medium gray stones, which is why I couldn't find any - medium gray and dark stone colors got merged at some point for 3d, apparently.
Actually, it looks like all those stones except granite had their BG color changed to 7. (I didn't check the non-gray stones to see if they changed too)
Anyways, veering back from that tangent, the problem isn't that granite reverses its color - it doesn't, it's light grey on black - it's that doors reverse BG and FG colors, and set brightness to 0, resulting in granite doors having a black foreground color because their BG color was black. Similar problems probably occur with things like cages and anything else that reverses fg:bg or anything like that.
Now, possible ways to fix this... Well, the only good ones I've thought of are:
1. Change it to the same color as some other kind of stone, either dark or light.
2. Change all the dark stone back to 0:0:1, and make granite 0:7:1 like normal stone. Problem: Dark stone stuff will be harder to see unless users adjust their init file color scheme (Or maybe I'm the only one with their monitor intentionally set to a very low brightness and contrast).
3. Make granite 0:0:1, which would make its doors look darker than other stone doors. This would work for doors because the identical-color-thing would give it a dark grey FG color - where gabbro etc have light grey. However, otherwise granite rocks and items and such would be just as dark as gabbro etc.
sphr:
I think I'll merge a few of your improvements back into my tileset too, like the black box lines around the X for bins, and the black pixels that you added around the white ON/OFF text which I had added to the levers. (And I just noticed the note you left on my user talk page, so I should look into that too - thanks, I hadn't noticed that mistake)