Operation Manual

Likewise, histograms can also depict a lack of contrast in an image. For example, an image
of a rainbow in the fog lacks contrast. Without directional lighting, there aren’t any
highlights or shadows in the image. In this case, the peaks of the histogram are
concentrated in the center and do not come close to either the dark or bright sides.
About Making Adjustments Onscreen
Human eyes perceive color subjectively. It’s difficult to make objective changes to the
colors in an image because the brain is so advanced that it skews the perception of colors
to make them appear as natural as possible. For this reason, it is essential that you create
the best possible work environment for performing color adjustments. Such an
environment excludes extraneous colors that have the potential to throw off your eye.
Creating a Good Work Environment
Before you begin making color adjustments to your images, it’s important to pay
attention to the following:
• Set your display to its highest-resolution setting. This will give you the best view of
your image.
• Make sure you are employing good color management. This means that your displays
and printers are calibrated and their profiles are up to date. For more information
about calibrating and profiling your Aperture system, see Calibrating Your Aperture
System.
• Reduce the ambient light in the room you are working in to prevent the light from
skewing your perception of the colors on your screens, and make sure your displays
are set to their brightest levels.
• If possible, paint the walls in the room in which you perform detailed image
adjustments a neutral gray. Keep bright-colored objects to a minimum to ensure that
the colors on your screens are not altered by the color in the rest of the room.
472 Chapter 16 An Overview of Image Adjustments