I changed now (in my personal version, not the official one)
SAND_TAN to 200,
SAND_YELLOW to 144,
SAND_WHITE to 178,
SAND_BLACK to 201 and
SAND_RED to 191
and it looks brilliant many thanks for your color table!
Where were you able to change the color values?
For a couple versions at least, my yellow sand has been more magenta than yellow. I normally don't embark in areas with sand, so it didn't really bother me that much until I had a patch of it right at the main entry of a recent embark:
I tried changing the SAND_YELLOW values from the inorganic_stone_soil.txt file from the LNP>graphics>Meph>raw>objects directory from
[INORGANIC:SAND_YELLOW]
[USE_MATERIAL_TEMPLATE:SOIL_TEMPLATE]
[STATE_NAME_ADJ:ALL_SOLID:yellow sand][DISPLAY_COLOR:145:7:0]158:7:0[TILE:141]
[SOIL][AQUIFER][SOIL_SAND]
[SOLID_DENSITY:1710] SCS = 90/5/5
to
[STATE_NAME_ADJ:ALL_SOLID:yellow sand][DISPLAY_COLOR:
204:185:0]158:7:0[TILE:141]
and also
[STATE_NAME_ADJ:ALL_SOLID:yellow sand][DISPLAY_COLOR:
204:185:0]204:185:0[TILE:141]
And it remained unchanged even after generating a new world.
I'm probably just too tired right now, but I looked through the LNP files a few times and didn't see much else I could tweak for how yellow sand is displayed. (My regular sand is more of a lime green, so I'd like to potentially adjust other colors too)
I was looking through the descriptor_color file, and the color codes in question there appear to be accurate when I plugged a few into paint.