Changing contrast of a text layer works as preview, but not after confirming

[X3nion]

Hey and Thanks for all your replies!

I will try your options as well. Finally, it worked out pretty well following the idea of PixLab, however with higher resolution, keeping the original picture size though. So one pixel is not that much anymore and hence I'm able to "dose" the resulting thickness.

Kind regards,
X3nion