One reason that Matte Pigments fail as a pressed powder is because they need a texturizing base which will help them be loose enough to give color payout, but also help them bind and stay pressed. In the following image, you will see a recipe which is a good base for pressing matte powders.
In addition to the dry base, you will also need to wet your pigments as usual before pressing. You may use TKB's MyMix Clear Pressing Medium or Jojoba Oil, or a medium of your choice.
