X-Rite Passport ColorChecker has been helping me for a while now and I am pleased with its performance as a color-managed workflow tool. I use it indoors or outside shoots and can quickly balance the white value and apply a calibrated camera profile to the images. The results are richer and truer colors. So far, nothing new, many readers know that much.
Use Passport ColorChecker in Scanning
I also use an Epson Perfection V500 Photo scanner to acquire scanned photographs or to directly capture images of objects, like flowers. When I capture an image via the scanner, I am not as sure of the colors as I am when the image comes from my camera. I thought the ColorChecker might come in handy, and I was right. Although its use is not as automated, nor is it necessarily sanctioned by X-Rite, as it is when used with a camera, it certainly makes sense to use it in the scanning workflow.
- Neutralize the scanning environment and start the process by resetting all the adjustments on the scanner software to not interfere with the color or exposure adjustments as we need a “raw” scan. Your equipment will differ from mine, so I am not going into a detailed explanation here. Make sure the scanner does not adjust the color or the exposure. (Click on the thumbnails to see them larger.)
- Open the Passport to lay flat on its face on the scanner glass and scan it with a little area outside. I scanned it at 300 dpi for this experiment and it may be a good idea to repeat this process using a few common settings you may use. Save the result in a TIFF file.
- Import the scanned image into Lightroom. (I must admit following a red herring a little bit. I thought I could create a DNG profile for the scanner as I can for my camera, and it would work like a charm. I converted the TIFF file to DNG and was even able to export to ColorChecker Passport. I even got the message that the DNG profile was created and Lightroom needed to restart. Alas, that profile never loaded for this image probably for some missing EXIF data in the file format.) So I took the long road.
- Use the white balance eyedropper and click on the third square from the left at the bottom of the set. That should give you a good white balance to the image, but it may be weak in the shadows. I noticed that the lighter shades of gray on the bottom rows of both the top and the bottom halves were “more neutral” than the darker shades. I do not have a satisfactory explanation other than speculating that “not all squares represent equal values or RGB.” You can refer to the highly detailed patch values and draw your conclusions. But that is splitting hair at this point (and I do not have much to split!)
- Although the white balance seemed fine, the low-end of the values were not deep enough for my expectations and highs lacked some brilliance as seen in the histogram after the white balance on the right. Using the Passport under an OttLite and observing the histogram behavior, I adjusted the exposure and Blacks on the “Basic” panel of Lightroom until slight clipping of the shadows was indicated. Since some crevices around the hinge did not probably receive sufficient exposure, I allowed them to slightly clip. On my system the exposure needed to go up +0.73 and the Blacks to 18. Remember that these are “eyeball adjustments”.
- When I was satisfied with the look of the Passport on my screen, which is calibrated and profiled with a ColorMunki by X-Rite, I saved the adjustments as a Lightroom Preset, Epson Scanner Profile, using the “profile” loosely.
- Now, the real test was in order. Lacking a flower to scan at the time, I pulled out an old photograph at random. I first scanned it just like I scanned the Passport with no adjustments. After that, I used the scanner controls to produce the best image I could at the scan time.
- After importing the scanned photographs, I simply applied the Epson Scanner Profile preset to the straight scan with one mouse click. The two images are below for you to compare:
Several things are worth noting. First, this is not a sanctioned use of the ColorChecker; it is an improvisation to satisfy my needs. Second, there is some guessing involved; your results may vary. However, working with a known original that you can inspect and compare to the screen image should be reasonably straightforward. Third, the scanner corrected image is not bad and can be tweaked with a little more adjustments in Lightroom. However, the accuracy of color will remain unknown. Fourth, the 1-click corrected image may look a bit too dark in the shadows; but I would rather deal with luminosity issues than color balance. To me, that is a more straightforward adjustment.
Now, if I could find someone to show me how to use the DNG profile I created in my attempts to automate the process I will be a much happy camper. Then, I will be using a color correction that is made by the DNG profiler using the known values of the color patches. That should take most of the guesswork out of this process. How about it X-Rite?
Below are all the images used in this article that you can view as a gallery.