Thursday, May 31, 2007
Calibrate Your Camera
To get complete predictability, consistency and control, it's important to calibrate your entire system. We used to do it with film, now we do it a little differently with digital gear.
Once you have this LAB file, you can set up Photoshop to compare the HSB numbers for the patches on both the real target and the "ideal" LAB target. Set up Color Samplers for the Red, Green and Blue patches, then change the readouts to HSB numbers. You can do this by clicking on the little eyedropper icon next to the numbered sampler readouts in the Info palette and selecting from the flyout menu.
Place samplers in both the real-world file and the LAB reference file and compare the numbers.
The difference between the values will give you a clue for how to adjust the sliders in ACR to bring the values in the processed file closer to the values of the ideal. Start by entering the differences in H and S as slider values in the ACR Calibrate tab for Hue and Saturation in Red, Green and Blue. You'll have to process the file out and remeasure to find out if you hit the values. You'll probably have to do this a few times before you arrive at the best slider settings because the ACR sliders don't quite behave in a linear fashion.
Ideally, calibrating the Red, Green and Blue patches should cause the other colors to fall into place, but certain color patches may look slightly off.
It's useful to calibrate for the skin color patch, as skin tone is often the most important color and the most difficult to get right. Compare samplers for the light skin patch (second from the upper left) and readjust if necessary. You usually have to settle for a more orangelooking red patch to get the skin tone to match up properly.
Once you have a calibration you're happy with, you can return to the Adjust tab and set the other sliders to get the look you're after for a good default.
Think about how you prefer your color.
More contrast? More saturation? Put these into your calibration. Don't go overboard with creative adjustment because you can always tweak images on a case-by-case basis—you're just looking for a good starting place for the bulk of your photography.
After you're happy with the overall settings, change the white balance setting back to As Shot using the dropdown menu. ACR is now set up the way you want to see your default capture. As Shot allows for different white balance, depending on the shooting environment, and any incamera white balance or auto white balance for a particular scene.
Once you're happy with the settings, it's a simple matter of saving your adjustments and making them the defaults. You're calibrated!
Now, save your new camera default setting for all future captures from this camera. Select Save New Camera Raw Defaults from the Settings flyout. All the current slider settings are now saved as the new default.
For a more detailed examination of this camera-calibration procedure, check out Lee Varis' book Skin: The Complete Guide to Digitally Lighting, Photographing, and Retouching Faces and Bodies, at www.varis.com.
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