Adobe After Effects Motion Tile on adjustment layer is gray not black

[mirrors]

I've never had a problem like this but i started a new edit a few days ago and i noticed that when i made an adjustment layer and put the motion tile over it to get the black bars effect it came up with gray bars, i didnt think anything of it at first but once i rendered the clip i realized that still there were gray bars instead of black. How could i change the motion tile effect to create black bars instead of gray bars.The adjustment layer with the motion tile effect

[Michael Bullo]

Could the problem be that your comp background colour is grey, not black?