They are RGB colors, which HTML happens to use
RRGGBB
Red/Blue/Green on a scale of 00 - FF
FF0000 = Red; 00FF00 = Green; 0000FF = Blue; 000000 = Black; FFFFFF = White
However, what's not important is the color you use, but the index of where it's at.
In the colortable, the position of the color is important. Think of the colortable as a 16 x 16 grid. The first row (mostly grass) is 0 through 15, the second row 16 - 31, etc. In the actual scripts you need to use hex.
So if you wanted to use, for example, blue floor tiles, you'd have to modify two files:
groups.txt:
Code:
//*****************************
//1c = blue tile
//*****************************
ae 1c
af 1c
maptrans.txt:
Code:
// (1c) blue tile
ae 000 0210
af 010 0210
Then in the colortable or swatches you use in Photoshop, you could actually use what ever color you wanted to in there, as long as you put it in the correct position. In this example I used the two empty slots after the water 50. It would make sence that you use blue, but you can use whatever shade of blue. Since in this example it's next to the water, I'd make them a very light blue or something.
ae and af (174 and 175) are the position numbers. 000 and 010 are the altitude of where the tile gets placed and 0210 is the (hex) tile ID.
Both of these files need to be changed for it to work correctly. Then you also need to modify the colortable that the bmp uses. In Photoshop you'd need to go to Image -> Mode -> Color table and set a unique color. It would also be advisable to save the color table as something so you can use it in the future. Otherwise it will only work for whatever bmp you are currently working on.
If you don't need transitions for these then you are basically done.