ok i have no idea how to access that so can you tell me where i can find it in the blockland folder?
navigate to here
(ignore the crossed out folder name - i have multiple blocklands in the blockland folder. yours will be under config/server.)
now make sure your server is closed (otherwise when you save and restart BL, it will overwrite the changes you made to your colorset)
when you open up your colorset.txt, you'll see something like this:
the numbers represent R G B A and the DIV's represent the color column name.
values are on the 0 to 255 scale; A stands for alpha e.g. transparency. 255 is opaque while 0 is 100% transparent.
just change all 255 values to 254, then save and start up bl.