I'm having trouble with tile

I am having trouble engraving on tile

![20210210_233623|375x500] (upload://gqnHati77NCcktSKLLakbU8V8.jpeg) none of my attempts have any contrast. Starting with white tile painted white, and others painted black. Then I did a ramp test to find the best focus length of my lense because I was using auto focus. after finding the best spot I then ran a tile power test and now completely confused because there is no good contrast on my test tile.

I have a c02 150w laguna laser. Ruida controller, and lightburn software