Problem with Tile engraving


I started today with Tile engraving.

Yesterday I painted Tiles (100mx100mm, matt White) with Glossy white.
Today I focussed my Laser first (Orthur Laser Master 2 20W Version) on a Black Paper and the I do Burning tests with 1200mm/min and 12% Power to fine Tune the Laser.

Then i printed a Test tile and here are some Problems It seems okay at 85% when I go under 77,5% the laser often didn’t not engrave the hole “test square”.

I don’t get any darker Squares so I “took the best” and Engrave a Picture of my Son but this came out very terrible.

Do you guys have any suggestions how I can improve. The main problem for me is that I can’t get any “dark” Engravings.

Did I use to less spray paint on the tile maybe?

It doesn’t take much of a paint coat to work. Plus, I’m wondering about a “matte” tile vs. a glazed.

Use Rustolium 2X flat white paint.
I put down two light coats and make sure that the tile is wet all over.
Don’t use gloss paint. It has a tendency to reflect the beam.
If a tile turns out too light, I simply repaint it and burn it again.
For picture engraving I have been using 60IPM 80% power (J-Tech 7 watt) and 231 DPI