If you are seeing a message that your crop marks are not detected in the ColorChecker plugin, try the following steps to troubleshoot your issue.

• Make sure that your ColorChecker Classic target covers at least 10% of your image area. Try cropping in to the ColorChecker if applicable to make sure that you have a large enough image.
• Check for background elements with repeating patterns that may be throwing off the automatic detection.
• Verify that there are no objects in your photo that may be blocking the target.
• Confirm that your target is rotated to be in plane with your camera lens, that the image is properly exposed, and that you have a sharp focus on your target.

In cases where steps above do not resolve your issue, try exporting your image as a DNG and using the ColorChecker standalone software to manually detect the crop marks. Make sure the green mesh is correctly aligned to cover every patch of the target.