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KB 2079

Corrupt thumbnails due to WCS incompatible profile

Last updated: 20-04-2017


My thumbnails appear corrupted, with large solid color blocks affecting parts of the image, but the viewer preview is rendered properly. The images also appear corrupt in other programs, such as Outlook. What's going on?


Capture One for Windows utilizes the Windows Color System (WCS) to include custom monitor profiles in the calculation to render accurate thumbnails. However, it is possible to generate an "incompatible" monitor profile using custom profiling tools, such as i1Profiler, which results in the corruption of the thumbnails. WCS is also used by other applications, such as Outlook, and the same images may appear corrupt in those applications as well. WCS is not used when rendering the Capture One viewer preview which this is why the previews appear properly. 

The most common incompatibility is generated when the profile is set up with the following:

  • Gamma/tone response curve of sRGB
  • Contrast Ratio: Measured Black Point (either set by the user or predefined)

These two parameters overlap somewhat and cause images to be rendered corrupt. Changing one or the other and re-profiling the monitor will resolve the issue.