It looks like especially small texts are drawn too bold since the change of GDI based text rendering to DirectWrite based rendering.

This effect can be seen when text is drawn onto transparent backgrounds like in a QQuickPaintedItem.

The difference can be seen in the attached screenshots (one using GDI, one DirectWrite). Especially on the white background a big difference can be seen in the small texts.

For reproduction, the attached source code snippets can be used. The mode (GDI/DirectWrite) can be switched using the constant UseGDI in testtranspquick.h