Strange problem with base of print

[dangre]

It looks like you have good exposure for the first layers then underexposure thereafter. mUVe3D has published some code to transition from the initial layer exposure to 'normal' layers:
Advanced Peel Control - Change Peel Settings For Effortless First Layer Adhesion
Using some of the advanced features built-in to Creation Workshop it’s possible to start a print with very slow peel speed and also a very tall peel distance. Then once adhesion has been guaranteed say 10, 20, or 100 layers in it is possible to speed that peel up to keep print times to a minimum. It’s also helps with parts that have a very large footprint that create a lot of suction, or with non-stick coatings that aren’t as “non-stick” as the others. Such as when comparing FEP to QSil.
Code can be found here:
http://www.muve3d.net/press/dlp-printer ... echniques/