With r_detailtextures you can set the detail of your textures in the game.
/seta r_detailtextures 0
Values: “0” to “1”
Having r_detailtextures set to “0” it gives you extra details on textures, but set to “1” it gives you a very bright effect which almost unsupportable. However in this case you can see the players better, because the contrast between the ground and the players is high.
Many servers restrict to “0”, but the default is “1” so there are lots of players kicked for this by PB.