A second method to do color balancing was tested to see if it produced a more accurate color rendition without the necessity of me doing a color balance by eye. I placed a Kodak gray card behind and around the gemstone. I then captured the image as usual. This (unretouched image) is shown in Photo 8.

Photo 8.

Histogram 2

Photo 9.

Photo 10.
Going to the Image menu and selecting Adjust Levels produced the histograph shown in Histogram 2. Notice the red-box at the lower right, this is an eye-dropper tool which can be used to sample the original image. It has the particular property, that when the image is sampled at a given point, that point is color corrected to true gray, and the entire image shifts accordingly. The resultant image is shown in Photo 9.

That final image, after background blurring, is shown in Photo 10. The image, although, corrected for a neutral gray background remains far too red-magenta in color. Notice also the difference between the non-blurred tweezers, and the final image with blurring. The tweezers become much less a focal point.

As a comparison I captured one additional picture of the original stone without the microscope and in real sunlight. It is shown in Photo 12 without any color correction. The final version done with eye correction Photo 11 and with the gray-card correction Photo 13 are shown too. The eye-corrected version is closer to the "real" color.

The preceding methods were tested before creating the images in the gemstone and mineral gallery. I ended up using eye-correcting for the images after capture, so although not 100% accurate, they are better representations than the non-corrected original versions.

Side by side
comparison ...
Photo 11

Eye Corrected
Photo 12

Photo 13

Gray Card
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