Help, I'm new :) -- shading too dark on some games in MAME

[n8cermak]

Hi everyone, a number of my MAME games for my Arcade cabinet are too dark, like the shading has been cranked up to 11!  It isn't all of the games that are impacted, just some important ones like the X-Men arcade game.  Is there a way to fix shading issues (if that is indeed the problem) on select titles/roms?  I don't even know where to start.  Thanks in advance.  I have attached an example picture, the shading issue is even worse in real life than the picture shows.