I have a peculiar problem - in FBS or albumin containing media my cells (preadipocytes) are very easy to image (and therefore quantify using a combination of ilastik and CellProfiler).
However, in animal component/serum free media their boundaries on our phase contrast microscope become very faint, pretty much invisible. So we're unable to quantify the cell confluency in our well plates/cultures.
Why are cells in serum free media harder to image? And are there ways to address this (e.g., differential interference contrast microscopy)?