ptg Adjustment Layer Basics 201 Merging and deleting adjustment layers When you merge an adjustment layer downward, the adjustments are applied permanently to the under- lying image layer. If you change your mind, either choose Edit > Undo (right away!) or click the prior state on the History panel. To merge an adjustment layer: Do either of the following: Click the adjustment layer to be merged downward, A then press Ctrl-E/Cmd-E. B Right-click on or near the adjustment layer name and choose Merge Down. Note: Adjustment layers don’t contain pixels, so you can’t merge them with one another. However, you can merge multiple adjustment layers into an image layer (or layers) by using the Merge Visible command (see page 145) or the Flatten Image command (see page 146). Adjustment layers are as easy to delete as they are to create. To delete an adjustment layer: Do either of the following: Click the icon for an adjustment layer on the Layers panel, then click the Delete Layer button on the same panel or the Delete Adjustment Layer button on the Adjustments panel. Click Yes if an alert appears. Optional: Click Don’t Show Again to prevent the alert from reappearing. Click the icon or layer mask thumbnail for an adjustment layer on the Layers panel, then press Backspace/Delete. (See also the sidebar at right.) A Click the adjustment layer to be merged downward. B e M e r g e D o w n c o m m a n d a p p l i e d t h e L e v e l s v a l u e s from the adjustment layer to the underlying image layer, which in this case is the Background. BYPASSING THE AUTO-SELECT PARAMETER OPTION ★ The new Auto-Select Parameter option (on the Adjustments panel menu) causes the fi rst entry fi eld on the panel to become highlighted automatically when you create an adjustment layer or when you double-click the icon for an existing adjustment layer on the Layers panel. Although this option enables you to quickly enter or change values, it can be an annoyance because it prevents some shortcuts from working (e.g., selecting a tool via its letter shortcut or deleting a layer by pressing Backspace/Delete). If this option is on and you want to shift the focus from the Adjustments panel to the Layers panel, click either the icon or the layer mask thumbnail for the adjustment layer. ptg 202 Chapter 12 Editing the adjustment layer mask By default, every adjustment layer has a blank white layer mask. To limit which area of the image the adjustment aects, you can add black areas to the mask, either by lling a selection or by applying brush strokes, as we show you in the steps below. To edit the adjustment layer mask: 1. Click the mask thumbnail on an adjustment layer. 2. Press D to choose the default colors, then press X to switch to black as the Foreground color. 3. To partially mask the adjustment layer eect, do either or both of the following: Create a selection with any selection tool (e.g., Rectangular Marquee or Lasso), choose Edit > Fill (Shift-Backspace/Shift-Delete), choose Use: Foreground Color, click OK, then deselect. Choose the Brush tool (B or Shift-B). On the Options bar, choose a Soft Round brush, Mode: Normal, and an Opacity of 100% (or a lower opacity to create a partial mask), adjust the brush diameter by pressing [ or ], then apply brush strokes to the image. A–C 4. Optional: To reverse the eect of the mask in specic areas, press X to switch colors (make the Foreground color white), then with the Brush tool, apply strokes to remove the mask. ➤ To remove all black areas from the mask, deselect, click the adjustment layer mask, choose Edit> Fill, then choose Use: White in the dialog. ➤ To conne the eect of an adjustment layer to a small area, start with a fully black mask (click Invert on the Masks panel or apply Edit > Fill, Use: Black), then apply strokes with white. ➤ To create a gradual mask by applying a gradient, see pages 244–245. To rene the edge or density of the mask, see pages 170–171. SHORTCUTS FOR LAYER MASKS View the mask by itself in the docu- ment window Alt/Option click the layer mask thumbnail (repeat to restore the normal view) View the mask over the image as a Quick Mask (the default color is red) Alt-Shift/Option-Shift click the layer mask thumbnail (repeat to restore the normal view) Deactivate or activate the mask Shift-click the layer mask thumbnail (Layers panel) or click the Disable/Enable button (Masks panel) Convert the unmasked area into a selection Ctrl/Cmd click the layer mask thumbnail (Layers panel) or click the Load Selection from Mask button (Masks panel) B We used Curves to correct the color, then with the mask for that adjustment layer selected, we applied brush strokes to the top part of the image. Now the adjustment is visible in only the bottom half of the photo. A i s o r i g i n a l p h o t o l o o k s t o o p i n k . C Our brush strokes are rep- resented by black areas in the adjustment layer mask thumbnail. ptg Adjustment Layer Basics 203 Using the Histogram panel e Histogram panel displays a graph of the current tonal (light and dark) values in an image, which updates dynamically as the document is edited. e panel is always accessible, even while the Adjustments panel is being used or an adjustment dialog is open. You can better judge how adjustment edits are aecting your document if you monitor the changes in its histogram. After opening a photo into Photoshop — but before you begin editing it — study the histogram to evaluate the existing distribution of tonal values in the image. e horizontal axis on the graph repre- sents the grayscale or color levels between 0 and 255, the vertical bars represent the number of pixels at specic color or tonal levels, and the contour of the graph represents the overall tonal range. To choose a view for the Histogram panel: From the Histogram panel menu, choose one of the following: Compact View (just the histogram), A Expanded View (the histogram plus data and access to individual channels), B or All Channels View (all the features of Expanded View, plus separate histograms for each channel). To display document data in the latter two views, check Show Statistics. For Expanded or All Channels view, choose an option from the Channel menu: RGB, C a specic channel, Luminosity, or Colors. To display the individual channels in color, check Show Channels in Color on the panel menu. While a large le is being edited, Photoshop main- tains the redraw speed of the Histogram panel by reading the data from the histogram cache — not from the actual image. When this is occurring, a Cached Data Warning icon appears on the panel. Remember to keep updating the panel, as we instruct you here (even while editing the settings for an adjustment layer), so it will continue to reect the current tonal values of the image. To update the Histogram panel: Do one of the following: Double-click anywhere on the histogram. Click the Cached Data Warning icon. Click the Uncached Refresh button. ➤ To specify a Cache Levels value in the Preferences dialog, see page 391. C With RGB chosen on the Channel menu, the current tonal values in the image are represented by black areas on the graph. B Here the panel is in Expanded View. By default, the Channel menu is set to Colors. A i s H i s t o g r a m p a n e l i s i n C o m p a c t V i e w . ptg 204 Chapter 12 Interpreting the Histogram panel To focus on tonal values when using the Histogram panel, choose Expanded View from the panel menu and choose RGB from the Channel menu. Pixels are represented by vertical bars in the graph, with shad- ows on the left, midtones in the middle, and high- lights on the right. For a dark, low-key image (such as a night scene), the bars will be clustered primarily on the left side of the graph; for an average-key image with more balanced lights and darks, the bars will be more uniformly distributed across the graph; and for a very light, high-key image containing few or no shadow areas, the bars will be clustered primarily on the right side. If an image has a wide tonal range, the bars will be more uniformly distributed in all the tonal zones, and will stretch fully from one end of the graph to the other. Also, the graph will be mostly solid and will have a relatively smooth contour rather than a spiky one. A If an image lacks detail in a particular tonal range, on the other hand, the graph will contain gaps and spikes, like teeth on a comb. e following are some graph proles that you might encounter: ➤ For an average-key but underexposed image that lacks details in the highlights, pixels will be clus- tered primarily on the left side of the histogram. B ➤ For an overexposed image that lacks details in the shadows, pixels will be clustered mostly on the right side of the histogram. C ➤ For an image in which pixels were clipped (details discarded) from the extreme shadow or highlight areas, a line or cluster of pixels will rise sharply at the left or right edge, respectively, of the histogram. D ➤ If an image has lost details as a result of editing (such as from lters or adjustments), the histo- gram will have gaps and spikes. E e gaps indicate a loss of specic tonal or color levels, whereas the spikes indicate that pixels from dierent levels have been averaged together and assigned the same value (the bar becomes taller at that level). A few gaps and spikes are an acceptable result of editing, whereas large gaps signify that posteriza- tion has occurred and too many continuous tonal values have been discarded. On the other hand, a lousy-looking histogram doesn’t always signify failure — the graph can be thrown o by some- thing as simple as adding a white border. If you like the way the image looks, ignore the histogram! A e t o n a l r a n g e s i n t h i s i m a g e a r e w e l l b a l a n c e d . B e h i s t o g r a m s h o w s t h i s i m a g e i s u n d e r e x p o s e d . C i s i m a g e i s o v e r e x p o s e d . D i s g r a p h s h o w s t h a t s h a d o w p i x e l s a r e c l i p p e d . E i s g r a p h c o n t a i n s g a p s a n d s p i k e s . ptg adjustments in depth IN THIS CHAPTER Correcting tonal values using a Levels adjustment layer . . . . . . . .206 Applying a Brightness/Contrast adjustment . . . . . . . . . . . . . . . .208 Applying a Photo Filter adjustment . .209 A quick and dirty method for correcting under- or overexposure .210 Dodging and burning small areas . . .211 Converting layers to grayscale via a Black & White adjustment . . . . .212 Applying a Vibrance adjustment . . . .214 Applying a Color Balance adjustment .217 Applying a Hue/Saturation adjustment . . . . . . . . . . . . . . . .219 Applying an Auto Color Correction . . .220 Correcting the color using Curves . . .222 Applying the Shadows/Highlights command . . . . . . . . . . . . . . . . .227 Applying a tint via a Solid Color fi l l l a y e r . . . . . . . . . . . . . . . . . . 2 3 1 Screening back a layer using Levels . .232 13 Upon opening a photograph into Photoshop, take a few minutes to study it and see if it has any tonal or color defects. Is it over- or under- exposed? Does it have a color cast (does it look ghostly blue or sickly green)? To some extent, the subject matter of the photo will dictate what kind of adjustments it needs. For instance, we might rebalance the skin tones in a portrait to make it look more natural, but apply a tint or photo lter to a photo of an abstract texture or to an extreme closeup for an artistic eect. If you capture your photo as raw les or in the JPEG or TIFF format, you will be able to rectify many of their defects in Camera Raw. If you can’t use Camera Raw for your les or they need further correction, not to worry: Photoshop oers a smor- gasbord of adjustment controls. Each adjustment type has a specialized function (see the icons below). Some are easy to get the hang of, and others may take longer to master but oer more power or more nuanced controls. In the preceding chapter, we stepped you through the mechanics of creating and working with adjust- ment layers. In this chapter, we delve into their specic features. e good news is that by the end of this chapter, you will have mastered most of the key Photoshop commands! BUTTONS ON THE ADJUSTMENT PANEL Invert Posterize Gradient Map Selective Color r e s h o l d Vibrance Hue/ Saturation Black & White Channel Mixer Photo FilterColor Balance Brightness/ Contrast Levels Curves Exposure Continued on the following page . D to choose the default colors, then press X to switch to black as the Foreground color. 3. To partially mask the adjustment layer eect, do either or both of the following: Create a selection. choose a Soft Round brush, Mode: Normal, and an Opacity of 100% (or a lower opacity to create a partial mask), adjust the brush diameter by pressing [ or ], then apply brush strokes to the image. A–C 4 color, then with the mask for that adjustment layer selected, we applied brush strokes to the top part of the image. Now the adjustment is visible in only the bottom half of the photo. A i