Sử dụng photoshop cs5 part 31 potx

ptg Colors & Blending Modes 191 CHOOSING A SAMPLE SIZE ➤ To change the size of the area from which the Eyedropper tool samples, on the Options bar, choose Sample Size: Point Sample (to sample the exact pixel you’ll click on) or one of the Average options (e.g., to sample an average value from a 5-by-5-pixel square area). ➤ You can also right-click in the document with the Eyedropper tool and choose a sample size from the context menu. ➤ The 3 by 3 Average and 5 by 5 Average options are useful for sampling continuous tones, such as skin tones in a portrait photo or the background area in a landscape (we usually use 3 by 3 Average). The 11 by 11 Average through 101 by 101 Average options are suitable for very high-resolution fi les. We’re choosing a Sample Size for the Eyedropper tool from the Options bar. A We checked Show Sampling Ring for the Eyedropper tool on the Options bar, then clicked a color in the image. Using the Eyedropper tool To sample a color from an image using the Eyedropper: 1. Choose the Eyedropper tool (or hold down I to spring-load the tool). 2. On the Options bar, do the following: Choose a Sample Size (see the sidebar on this page). Choose Sample: Current Layer (then click a layer) or choose All Layers. Optional: Check Show Sampling Ring. ★ 3. When you do either of the following, the sampled color will appear in the currently active square on the Tools and Color panels. If Show Sampling Ring is checked, the sampled color will also pre- view on the top part of a large ring and the cur- rent Foreground or Background color will preview on the bottom part. Click a color in any open document. A Drag in any document (the current color square changes dynamically), and release the mouse when the pointer is over the desired color. ➤ Alt-click/Option-click or drag in the document window with the Eyedropper tool to choose a Background color when the Foreground color square is selected, or vice versa. Copying colors as hexadecimals For Web output, you can copy colors as hexadecimal values from a le in Photoshop and then paste them into an HTML le. To copy a color as a hexadecimal value: 1. To copy a color to the Clipboard as a hexadecimal value, do either of the following: Choose the Eyedropper tool (I or Shift-I) and choose Options bar settings for the tool. Right-click a color in the document window, then choose Copy Color as HTML (HTML color tag) or Copy Color’s Hex Code ★ (HEX number). Choose a Foreground color via the Color panel, Color Picker, or Swatches panel. From the Color panel menu, choose Copy Color as HTML or Copy Color’s Hex Code. ★ 2. To paste the color into an HTML le, display the HTML le in your HTML-editing application, then choose Edit > Paste (Ctrl-V/Cmd-V). ptg 192 Chapter 11 Choosing a blending mode e blending mode A that you choose for a tool or layer aects how that tool or layer interacts with underlying pixels. You can choose from a menu of blending modes in many locations in Photoshop, such as the Options bar (for most painting and editing tools), the Layers panel, and the Layer Style and Fill dialogs. In the text that accompanies the gures in this sec- tion, the colors of existing underlying pixels are called the base colors; the color in the upper layer or that you apply with a tool (such as the Brush), and that you choose a mode for, is called the blend color. In all the images, we used the same three color squares, as shown in the rst gure below (Normal mode). To avoid con- fusion, we kept the blend layer opacity at 100% (except for Dissolve mode). ➤ For most blending modes, Photoshop compares the colors of the two layers (or the layer and the paint color being applied by a tool) on a channel-by- channel basis. For example, the lightness of a pixel in the Red channel of the blend layer is compared to the lightness of a corresponding pixel in the Red channel of the base layer. ➤ When choosing an Opacity percentage for a tool (via the Options bar), keep in mind that the impact of the tool is also aected by the opacity of the layer that strokes are applied to. For example, strokes applied with a Brush tool of 50% opacity on a layer opacity of 50% will appear lighter than the same strokes applied to a layer that has an opacity of 100%. CYCLING THROUGH THE MODES To cycle through the blending modes for the cur- rent painting or editing tool, or for the currently selected layer if a nonediting tool (such as the Move tool or a selection tool) is being used, press Shift - + (plus) or Shift - – (minus). Normal All the base colors are modifi ed. (When an image is in Bitmap or Indexed Color mode, this mode is called Threshold.) THE BASIC BLENDING MODES REPLACE THE BASE COLORS Dissolve (50% Opacity) Creates a chalky, dry-brush texture using the blend color. The higher the pressure or opacity of the tool (and the higher the opacity of the layer), the more solid the color. A  e b l e n d i n g modes are grouped according to their function and eect. Basic Darken Lighten Contrast Comparative Component ptg Colors & Blending Modes 193 THE DARKEN BLENDING MODES DARKEN THE BASE COLORS Darken The blend color tints the base color. Multiply A dark blend color produces darker base colors; a light blend color merely tints the base colors. Good for creating semitransparent shadows. Color Burn Increases contrast in the base color by darkening the shadow areas and lightening the highlight areas. Linear Burn Uses the blend color to darken the base colors by decreasing brightness. Darker Color The blend color replaces base colors lighter than itself without affecting darker base colors. The blend color is fully opaque. Could be used to “paint out” light colors on an underlying layer without having to use a selection.  e l i g h t b l u e s t r o k e s were applied to a blank layer above the image layer. e layer that contains the brush strokes has a blending mode of Darker Color. Continued on the following page ptg 194 Chapter 11 THE LIGHTEN BLENDING MODES LIGHTEN THE BASE COLORS Color Dodge A light blend color lightens the base colors by decreasing the layer’s contrast; a dark blend color tints the base colors slightly. Linear Dodge (Add) A light blend color lightens the base colors by increasing the layer’s brightness; a dark blend color tints the base colors slightly. Screen A light blend color produces lighter, bleached base colors; a dark blend color lightens the base colors less. Lighten Modifi es only base colors that are darker than the blend color, not base colors that are lighter than the blend color. Lighter Color The blend color replaces base colors darker than itself without affecting lighter base colors. The blend color will be fully opaque. Could be used to “paint out” dark colors on an underlying layer without having to use a selection.  e l i g h t b l u e strokes were applied to a blank layer above the image layer. Lighter Color blending mode is chosen for the layer that contains the brush strokes. ptg Colors & Blending Modes 195 Linear Light Burns (darkens) the base colors by decreasing their brightness if the blend color is dark; dodges (light- ens) the base colors by increasing their brightness if the blend color is light. Pin Light A light blend color replaces the base colors; a dark blend color merely tints the base colors. Vivid Light Burns (darkens) the base colors by increasing con- trast if the blend color is dark; dodges (lightens) the base colors by decreasing contrast if the blend color is light. Hard Light Screens (lightens) the base colors if the blend color is light; multiplies (darkens) the base colors if the blend color is dark. Increases contrast in the blend color. Good for composite effects or for painting glowing highlights. THE CONTRAST BLENDING MODES INCREASE OR DECREASE THE OVERALL CONTRAST Overlay Multiplies (darkens) dark base colors and screens (lightens) light base colors while preserving luminos- ity (light and dark) values. Black and white pixels aren’t changed, so details are preserved. Soft Light Softens the base color by applying a light tint. Preserves luminosity values in the base colors. Continued on the following page ptg 196 Chapter 11 THE COMPARATIVE BLENDING MODES INVERT THE BASE COLORS Difference Inverts the base and blend colors. The lighter the blend color, the more saturated the resulting color. Exclusion Grays out the base colors where the blend color is dark; inverts the base colors where the blend color is light. Lowers contrast. Subtract ★ A light blend color darkens the base colors; a dark blend color tints the base colors with the invert value of the blend color. Divide ★ A light blend color tints the base colors; a dark blend color preserves dark tonal values in the base color and whites out all other colors. Hard Mix Posterizes (reduces) the base colors to approximately 5–8 fl at colors. A dark blend color produces more black in the base colors; a light blend color pro- duces more white in the base colors. Contrast blending modes (continued) Hue applies just the hue of the blend color; satura tion and luminosity values (and whites and blacks) in the base colors are preserved. Saturation applies the saturation of the blend color without changing hue and luminosity values in the base colors. Color applies the saturation and hue of the blend color but preserves luminosity values (details) in the base colors. This a good mode to use for tinting. Luminosity replaces luminosity values in the base colors with luminosity values from the blend color; hue and saturation values in the base colors are unchanged. THE COMPONENT BLENDING MODES APPLY A SPECIFIC COLOR COMPONENT . the sampled color will also pre- view on the top part of a large ring and the cur- rent Foreground or Background color will preview on the bottom part. Click a color in any open document. A Drag. as hexadecimals For Web output, you can copy colors as hexadecimal values from a le in Photoshop and then paste them into an HTML le. To copy a color as a hexadecimal value: 1. To copy. interacts with underlying pixels. You can choose from a menu of blending modes in many locations in Photoshop, such as the Options bar (for most painting and editing tools), the Layers panel, and