BUG
Concise problem statement:
Steps to reproduce bug:
- Create simple PCB with pad, track and two solder mask apertures:
- View it in Photo View:
- Compare with the (correct) rendering when viewed in Gerber Viewer:
Results:
Photo View renders Solder Mask aperture over copper and over exposed FR4 laminate as copper area.
Expected results:
Photo View should render Solder Mask aperture over copper as copper area but should show exposed FR4 laminate as some other colour (suggest blue-grey).
Browser: All
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Easy to use and quick to get started. 
This is a well-know problem, we don't have a way to fix, but our gerber viewer will make it better