Digital Photography Hacks [Electronic resources] نسخه متنی

Hack 71 Intelligent Auto Color Correction

Photoshop CS includes a helpful Auto Color
function. The problem is that it needs to be calibrated.
Here's a calibration how-to that reveals the secret
to fast color correction.

Our everyday world is a mishmash of
lighting. We read at home by tungsten lamp, ride to work under
overcast skies, and toil at the office beneath fluorescent tubes. We
normally don't think about all these different
lighting situations, because our eyes and brain automatically
correct what we see. Our environment, at least
in terms of lighting, appears relatively consistent.

This isn't the case for digital cameras. As
wonderful as their little computer brains are,
they're not as powerful as our human brains; they
have a more difficult time rendering the world in a consistent light.
As photographers, we can assist our digital cameras by taking care to
set the white balance as accurately as possible. But even with our
best efforts, we sometimes need to correct the color in
postproduction, to render skin tones and the overall environment in
the same light that our eyes perceive.

Color correction is one of the most difficult tasks in digital
photography. You can spend a lot of time fiddling with it and still
not get the results you want. This hack will change all that. By
combining two handy functions in Photoshop CS, you can correct color
quickly and accurately, enabling you to process an entire folder of
images in short order.

The secret starts with opening the Curves dialog box
(ImageAdjustmentsCurves). Click the Options
button to reveal a second dialog box. Enter the settings shown in
Figure 6-19 and be sure to check the
"Save as defaults" box. Click OK to
close both dialog boxes, and save your image.

Figure 6-19. Setting your auto color defaults in the Options dialog box

Open another image from the same batch of photos. This time, choose
the Auto Color function (ImageAdjustmentsAuto
Color). Photoshop will use the settings you established earlier to
correct the picture. Many times, you'll be finished
at this point, because the color correction will be close enough for
most tastes. If so, save the image and move on.

If, however, the Auto Color function overcorrected your picture,
making it too cool or too warm, you have a nifty option to back off a
bit. After you run Auto Color but before you do anything else, enable
the Fade command (EditFade). Fade
is one of those magical tools that, once you discover it,
you'll use for a variety of purposes. Fade allows
you to back off the last adjustment you madein this case,
color correction.

If you move the slide indicator all the way back to 0, the image will
return to its original state (before you applied the color
correction). If you leave the indication at 100, the full correction
stays intact. But, if you move the indication to the left, from 100
toward 0, you'll see a percentage of the color
correction that has been applied. So, if the original shot was too
warm and the Auto Color correction was too cool, using the Fade
command to back off the correction to 70% might be just right, as
shown in Figure 6-20.

Figure 6-20. Using the Fade command to back off the intensity of the last correction

Once you find that sweet spot, use Save As to indicate in the
filename that the color in the picture has been corrected. Once
again, your world appears as it should.