Chapter Ten Essential Image Enhancement

Evaluate the Image Use full screen (press ‘F’) in Photoshop to view the whole image Check exposure (histogram may help) Check color balance (use various eyedroppers) Check focus and sharpness (check Actual Pixels, Ctrl-Alt-0)

Safe image handling First thing to do after download: Backup Either save your images in a ready-only folder, or burn them on a CD Open your JPEG images and save them as PSD files while editing Save different versions of an image as different files Keep your original images as the background copy; all re-touching is done through layers. Use the History palette to undo mistakes.

Global Tonal Correction Adjusting the brightness of your image Potentially destructive to image details Instead of directly adjusting the background image, we apply any adjustment as a layer.

Adjustment layers The “effect” of an adjustment layer can be discounted by lowering its opacity. The “scope” of an adjustment layer can be restricted by layer masks. The “effect” of an adjustment layer can be “blended” into the background image through various blending modes.

Measuring tonal values with Info palette

Color Samplers Select eyedropper Shift-click on image to add color samplers

Levels Very useful tool for photographic images

Adjusting Highlight, Shadow, and Midtone in Levels Shadow Highlight Midtone Levels Eyedropper

Finding the brightest and darkest points in Levels Alt-click the shadow slider and slide it to reveal the darkest points Alt-click the highlight slider and slide it to reveal the lightest points

Using the Levels Eyedroppers to set white and black points Use the shadow eyedropper to set the black point of the image by clicking a point that you think is the darkest Use the highlight eyedropper to set the white point of the image by clicking a point that you think is the lightest

Curves A useful tool for adjustment image contrast.

Identifying tonal values on the curve Ctrl-click a point in the image to find the corresponding tonal value on the curve.

Adding contrast with an S-curve Add a curves adjustment layer Select a bright point for increased brightness Select a dark point for increased darkness Move the bright point up and move the dark point down on the curve

Reducing contrast with a reverse S-curve Add a curves adjustment layer Select a bright point for decreased brightness Select a dark point for decreased darkness Move the bright point down and move the dark point up on the curve Useful for images with too much contrast, e.g. harsh sunlight

Additive and subtractive color models

Color correction with Variations Show simultaneously several different results Not applicable as an Adjustments Layer No “zoom” view of results

Color Balance Add a Color Balance Adjustment Layer Adjust the individual color components