I’m sure you’re familiar with the most commonly used color correction features that Photoshop has to offer. These include Brightness and Contrast, Levels, Curves and Hue/Saturation that are the nuts and bolts of color and contrast adjustment. These features are absolutely critical to produce quality images. If you look at the new Photoshop CS4 Adjustments panel (see Figure 1) however, you’ll see several additional icons including a few new ones. The icons represent specific color alteration methods that when accessed, display the features’ controls in the panel and offer an extended range of color manipulation. In addition, there are features deep within the program that can simplify color correction.   

Figure 1 The new CS4 Adjustments panel displays icons that represent a variety of color correction features.

CALIBRATE AND MEASURE

Although I’ve said it before in other articles, it’s worth saying again: before you perform a color adjustment, scrutinize your image carefully to determine what the colors on your monitor actually represent. First, be sure to calibrate your monitor using hardware devices; a colorimeter and a spectrophotometer to create an accurate ICC profile that displays accurate color qualities of your monitor and your printer before performing any color adjustments.

With a reliable image displayed on screen, view the image’s histogram to determine the range of colors and measure a specific white point or black point with the Color Sampler tool and the Info panel.

 

EXPOSE YOURSELF

One of the most common miscalculations when an image is captured with a digital camera is the exposure. Usually photographers guard against under- or over-exposure by bracketing. Bracketing consists of shooting a series of pictures with a variation of exposure of one half to one full stop. This works well when a picture is planned but isn’t possible for one-of-a-kind candid shots. Indeed, it can be quite frustrating if the picture is taken exactly at the right moment with perfect composition and later realizing that the exposure is too light or too dark.

Enter the Exposure adjustment in the Adjustment panel. It can readily repair a bad exposure within certain limitations. It was originally designed to correct bracketed images being converted to 32 bit HDR, but works equally well on 16 and 8 bit images.

The panel consists of three tonal sliders:

The eyedroppers in the panel adjust brightness values.

You can see the results of an exposure adjustment in Figure 2. This underexposed image was completely  transformed with a fairly robust exposure adjustment and a modest gamma tweak. The results are  dramatic but quite different than applying a simple Levels adjustment because specific areas of  brightness in the overlapping ranges of highlight, midtone, and shadow are be targeted and modified.  Furthermore, when you apply Exposure or any other adjustment with the Adjustment panel, an adjustment  layer is automatically created allowing you to further modify the tonality with opacity or blend modes.

Figure 2 Dramatic results are achieved when the Exposure adjustment is applied to an under-exposed image.

PHOTO FILTER

Warming or cooling an image might be just what is required to smooth its overall tonality. The Photo Filter lets you apply the affects of traditional photographic filters. These filters produce results that are commonly used by photographers to warm or cool the colors of an image, reduce glare or simulate a specific atmospheric environment. Click the icon in the Adjustments panel or if other adjustment controls are currently displayed click the Panel Options menu and choose Photo Filter. In the panel choose a specific filter from the menu or a specific color by clicking the swatch. Control the amount of the application by moving the density slider between 1 and 100 percent. The Preserve Luminosity box, when checked, preserves the brightness values of the image.

Warming Filter (85) and (LBA),and Cooling Filter (80) and (LBB) are color conversion filters that target the white balance in an image. If an image was photographed at a lower color temperature of light it will appear yellow. Cooling Filter (80) moves the colors toward the higher temperature range so that they appear bluer to compensate for the lower color temperature of the ambient light (see Figure 3). Conversely, if the photo was taken with a higher color temperature of light it will appear blue when the Warming Filter (85) is applied.

Figure 3 The before and after results of applying the Cooling Filter 80 at 51% density to an image shot in a very warm light.

Warming Filter (81) and Cooling Filter (82) apply minor adjustments to balance the color quality of an image. Individual Colors apply a hue adjustment to the image depending on the color preset you choose. Your choice of color depends on how you’re using the Photo Filter adjustment. If your photo has a color-cast, you can choose a complementary color to neutralize the color. You can also apply colors for special color effects or enhancements. For example, the Underwater color simulates the greenish blue color cast in underwater photos. Check the Preserve Luminosity box to apply the filter without darkening the image.

 

GOOD VIBRANCY

You can change vividness and purity of color with the Vibrance panel. Vibrance is similar to saturation except that it adjusts the color intensity with minimal clipping as colors approach full saturation. It increases the saturation of less-saturated colors proportionally more than the existing intense colors, and also guards against oversaturation in flesh tones.

Note: Clipping occurs when the color values of a pixel are higher than the highest value or lower than the lowest value that can be represented in the image. Overly bright values are clipped to output white, and overly dark values are clipped to output black. The result is a loss of image detail.

To access the Vibrance controls, click the Vibrance icon in the Adjustments panel.

Drag the Vibrance slider to the left to increase or to the right to decrease color saturation without clipping the colors. To apply the same amount of saturation adjustment to all colors regardless of their current saturation, move the Saturation slider. In some situations, this may produce less banding than the Saturation slider in the Hue/Saturation Adjustments panel or Hue/Saturation dialog box. To decrease saturation, move either the Vibrance or the Saturation slider to the left. You can see the before and after results in Figure 4.

Figure 4 The before and after results when Vibrance  is applied to an image.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SHADOW/HIGHLIGHT
The Shadow/Highlight command quickly corrects over and under exposed areas of an image. This adjustment is not represented in the Adjustment panel and presents a rather formidable dialog  box. Choose Image > Adjustments > Shadow/Highlight to display the dialog box.Shadow/Highlights corrects each pixel adaptively, according to the luminance of the neighboring pixels. This allows image contrast to be increased in the shadows or highlights without significantly sacrificing

 contrast in the other tonal regions, which is essential for bringing out detail in over-exposed or backlit images, as in Figure 5.

Figure 5   Shadow/Highlight adjusts the contrast of overexposed or backlit images.

The sliders represent three aspects of the adjustment:

COLOR ADJUSTMENT

After you’ve applied the Shadow/Highlight command you may find that the image has acquired an undesirable color-cast. Click the Show More Options check box at the bottom of the dialog box and move the Color Correction slider in the Adjustment box to the left to diminish the overall adjustment. Moving the slider to the left decreases the saturation of the image. Moving it to the right increases the saturation.

 

MIDTONE CONTRAST

Increasing or decreasing the Midtone Contrast slider in the Adjustment box produces an overall contrast adjustment that may be just what you need to really pop the image.

The Black Clip and White Clip percentage fields enable you to enter a value for the amount that absolute black and specular white will be altered. By entering a value of 5 percent, for example, the value of 95 percent black will be increased to 100 percent, and all other colors will be remapped accordingly so the image will appear darker.

The techniques featured in this article are direct and easy to perform, and they produce great results. In future articles for Sign & Digital Graphics magazine I will reveal more Photoshop secrets and combination techniques—and believe me, there are a lot of them—that empower you to produce outstanding pictures composed of brilliant color, enhanced contrast and result in knock-your-socks-off impact.