Passing any RGB string it seems that at least one R,G or B must be above 216 otherwise the pixel goes out.
Testing shows:
This works "217,0,0" = red background.
This gives blank background "216,0,0"
This gives blank background "216,216,0"
This gives green background "217,217,0"
Passing any RGB string it seems that at least one R,G or B must be above 216 otherwise the pixel goes out. Testing shows: This works "217,0,0" = red background. This gives blank background "216,0,0" This gives blank background "216,216,0" This gives green background "217,217,0"