[Typo3] Image with 'nicetext' to blurry

[Maurice Zeijen]

I am generating a number of header images with text that is renderd with 
niceText. The problem is that the text is to blurry and I don't seem to 
get it more crispy (the sharpen property doesn't do anything). I use GD 
   version "bundled (2.0.28 compatible)" and ImageMagic version 6.1.6. 
Does anyone know how I can get the text crispy without losing the 
quality that nicetext provides?

Maurice