Increasing Color Saturation

© 2002 Gregory Georges
© 2002 Gregory Georges

ABOUT THE IMAGE

Deep in the Forest Canon EOS D30 digital camera, 28-70mm f/2.8 @ 48mm, ISO 100, f/18.0 @ 1/4, Extra Fine RAW setting, 1440 x 2160 pixels converted to 18.7MB 48-bit .tif

Over time, I have learned that when shooting toward a magnificent sunset or sunrise, you should also turn around and shoot behind you, too. While taking early morning sunrise photos of a foggy swamp, I turned around and shot the photo shown in Figure 9.1.When I looked at the LCD on my digital camera, I was astounded to see the contrast between the rich bright orange and yellow leaves and the deep blues and greens of the forest.

In this technique we look at how you can exaggerate the colors and make an even more color saturated rich, mossy, foggy, deep inside the forest image — one that looks like it would be the perfect place to find a unicorn! To achieve our objectives, we use a combination of the Multiply blend mode, Curves, and Hue/Saturation.

STEP 1: OPEN FILE

■ Choose File ^ Open (Ctrl+O) to display the Open dialog box. Double-click the \09 folder to open it and then click the forest-before.tif file to select it. Click Open to open the file.

■ Choose View ^ Fit on Screen (Ctrl+0) so that you can see the entire image.

STEP 2: IMPROVE TONAL RANGE

Once again, we have the advantage of working with a 48-bit image. But this time, unlike what we did in the last technique, we take full advantage of the extra picture information and make the initial tonal corrections before changing to 24-bit mode (8-bits per color channel).

■ Choose Image ^ Adjustments ^ Levels (Ctrl+L) Quickly take a look at the Red, Green, and Blue histograms by clicking the Channel box and selecting each channel to see if it is optimized to show the best tonal range. You notice that some of the tail ends in some channels are lacking data, indicating that the tonal range can be improved. A good example of such a channel is the Green channel histogram, as shown in Figure 9.3.

■ Click in the Channel box and select Red. While pressing Alt, slide the left slider in toward the middle until you just begin to clip some of the shadow data, as shown in Figure 9.4. When the first Input Levels box shows 25, you have clipped just about all the shadow data that you want to clip.

■ While pressing Alt, slide the right slider in toward the middle until you just begin to clip some of the highlight data. The third Input Levels box should be at about 250 and the Levels dialog box should look like the one shown in Figure 9.5.

Moving the left or black-point slider in toward the middle makes all those tones lower and to the left black. With a setting of 25, all tones between 0 and 25 now become pure black, which makes all the tones

between 26 and 255 stretched between 0 and 255. The result of this stretching is an increased tonal range or image contrast. The same holds true for sliding the right or white-point slider, except in this case you are setting the tones to the right of the slider to white and further stretching the remaining points between 0 and the value you set. After doing this to all three channels, you have an image that has black darks and pure white whites.

■ Click in the Channel box in the Levels dialog box and select Green (Ctrl+2). While pressing Alt, slide the left slider in toward the middle until you just begin to clip some of the shadow data. When the first Input Levels box shows 18, you clipped just about all the shadow data that you want to clip.

■ While pressing Alt, slide the right slider in toward the middle until you just begin to clip some of the highlight data. When the third Input Levels box shows 236, you clipped just about all the highlight data that you want to clip.

■ Click in the Channel box in the Levels dialog box and select Blue (Ctrl+3).

■ While pressing Alt, slide the left slider in toward the middle until you just begin to clip some of the shadow data. When the first Input Levels box shows 5, you clipped just about all the shadow data that you want to clip.

■ While pressing Alt, slide the right slider in toward the middle until you just begin to clip some of the highlight data. When the third Input Levels box shows 239, you clipped just about all the highlight data that you want to clip.

■ Click OK to apply the Levels settings.

The image looks much better with the wider tonal range. Now darken and increase the color saturation to create a deep inside the forest look. To do this, we are going to need to increase color saturation. If you are thinking that we can do that with Levels and Hue/Saturation, you are thinking correctly; but we are going to use an adjustment layer to give us more control. Plus, because we want to make some pretty severe changes in the blue and green colors, we first select the orange and yellow leaves to make sure they don't get bathed in an unwanted color.

■ As none of the color selection commands we will be using are available when editing an image in 48-bit mode, we have to change modes to select the leaves. Also, we can't use adjustment layers in 48-bit mode either so choose Image ^ Mode >-8 Bits/Channel.

As you change from a 48-bit image to a 24-bit image, the size of your image decreases by 50%. This image file decreased from 17.8MBs to 8.9MBs. You can see these changes either by setting the Status Bar to show Document Sizes, or you can choose Image ^ Size to read the file sizes.

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