Photoshop cs5 cho nhiếp ảnh gia part 30 ppt

and you cannot eliminate them using the subtract From eyedropper, the Fuzzi-ness slider, or the Range slider, use any of the other selection tools such as the Lasso or Magic Wand tool to

Figure 4.34 The Localized Color Clusters option makes

it possible to limit the area that’s selected when the color appears in multiple parts of the image

white area into a selection

and you cannot eliminate them using the subtract From eyedropper, the Fuzzi-ness slider, or the Range slider, use any of the other selection tools (such as the Lasso or Magic Wand tool) to remove them from the selection

Note: You can use more than one color as the basis for your selection by selecting the middle eye-dropper and clicking an additional color in your image Similarly, you can use the farthest-right eyedrop-per to click a color range to remove from your selection

the Color Range tool tends to create selections with slightly blurry edges, whereas the Magic Wand creates more definite selections with anti-aliased edges of course, any selection can be modified using the Refine Edge tool

the Masks panel uses the Color Range tool to help create and adjust layer masks We’ll talk more about that in Chapter 6

Combining Tools

We’ve covered some of the key selection tools here to help you build a foundation for the use of tools within Photoshop as well as get you started on creating selections you’ll use to apply targeted adjustments to your images in Chapter 8, “Composites,”

we’ll explore additional, more advanced ways of making selections However, we want

to stress here that you can mix and match any of the selection tools or methods in

Photoshop to create the perfect selection it’s fine, and often helpful, to begin a selec-tion with one tool and use another tool to refine it, as you saw earlier with the combi-nation of Quick select and Refine Edges (Figure 4.31)

in the workshops we teach, we often see participants getting stuck on a single selection tool for a given task For example, if they’re trying to create a selection of the sky, they naturally start with the Magic Wand tool if that tool isn’t providing a good solution in a particular portion of the sky, we often see the person struggling to find just the right tolerance setting and just the right pixel to click in order to get the

selection perfect the result is a lot of frustration as the photographer has to repeatedly

undo a step in the selection process and then redo that step with different settings

You can avoid (or at least minimize) this sort of frustration by combining vari-ous selection tools to create a selection For example, when selecting a sky, you might

start with the Magic Wand tool to create a basic selection and then employ the Lasso

tool to clean up that selection and the areas the Magic Wand tool wasn’t able to select

effectively always keep in mind that every tool or method for creating a selection in

Photoshop can be utilized in building a selection add or subtract from the selection as

appropriate, using the means most appropriate for each given area of the selection as

you work to create the final result

Saving and Loading Selections

after you’ve created a selection, particularly if it was time-consuming and/or

challeng-ing, you probably want to save it for future use, just in case once you save a

selec-tion and then save the image file in an appropriate format (such as Photoshop Psd or

tiFF), the selection is then saved as part of the image file, so you can always reload

the selection in the future if needed

Note: Selections are saved as alpha channels As you may know, RGB images are composed of

individual channels that describe the amount of red, green, and blue light that should be combined to produce the color value for each pixel An alpha channel is a special channel in addition to these RGB channels, and it is generally used to store selections for an image

to save a selection, choose select > save selection from the menu, which opens the dialog shown in Figure 4.35

Figure 4.35 The Save Selection dialog box

allows you to specify a name (as well as other settings) for the selection you are saving

although you can save selections in different documents with the same dimen-sions, it’s generally best to save your selections within the image for which you’ve

cre-ated the selection therefore, leave the document setting to the default value, which is

the name of the current document

the Channel drop-down list should be set to new so the selection is saved as

it is if an existing selection has been saved, you can also choose that selection from

the Channel drop-down list and merge the current selection with the previously saved

name is the key setting (and generally the only one you need to change) in the save selection dialog box Be sure to save the selection with a descriptive name that will make sense to you in the future when you need to load a selection, since you may

be choosing a selection from a list of names when you load it

if you’re using the new option from the Channel drop-down list, the operation section of the dialog box has only a single option to create a new channel otherwise, you’ll have the same options as you have for each selection tool to create a new saved selection: add to Channel, subtract from Channel, or intersect with Channel When you click oK, the selection is saved as an alpha channel, which you can view on the Channels panel

Note: Saved selections aren’t truly saved until you save the image in which you stored them If you save a selection but then close the image without saving it, the selection isn’t saved

in the future, you can “load” the selection—that is, select the same pixels once again—by choosing select > Load selection from the menu and choosing the name from the Channel drop-down list, as shown in Figure 4.36

Figure 4.36 The Load Selection dialog box allows

you to recall previously saved selections

For Photoshop Elements Users: Saving and Loading Selections

The Save Selection dialog box in Elements, seen here, is simpler than the one in CS5 because Elements only lets you save (or load) the selection within the current document Keep in mind that when you save a selection within a JPEG image, you will have to resave the image as a PSD

or TIFF file

Note: Not all image file formats allow you to save selections, because they don’t all allow you to save alpha channels, which is how a selection actually is stored If you’re going to save a selection, it should be part of your master image file saved as a Photoshop PSD or TIFF image file

Brush Tools

as a nature photographer using a camera to produce artistic images, you may not

think you’d need to utilize the Brush tool in Photoshop after all, if you capture an

image with a camera, you certainly don’t need to draw an image from scratch

How-ever, there are actually many situations where you’ll use the Brush tool while

optimiz-ing your photos For example, we use the Brush tool extensively with safe dodgoptimiz-ing

and Burning layers and for painting on masks to identify areas where we want

tar-geted adjustments to apply (We’ll cover both of these topics in later chapters.)

Note: The Quick Selection tool we just covered is actually a form of a Brush tool, and the Clone Stamp and Healing Brush tools are advanced types of Brush tools that allow you to clean up your images We’ll cover those in Chapter 5, “Workflows and First Steps.”

the Brush tool allows you to paint pixels with great flexibility this comes

in handy for a number of different adjustments you can make by painting on a layer

with special properties or for painting on a mask (which you’ll learn about in later

chapters)—to change where adjustments will apply to your image, for example By

learning how to work with the Brush tool, you open up many opportunities for

mak-ing more advanced adjustments and takmak-ing full control of your images

to get started, create an empty document by choosing File > new from the menu the new dialog box appears Choose 5 × 7 from the Preset drop-down list,

make sure Color Mode is set to RGB, and click oK then select the Brush tool either

next, look at the color swatches on the tools panel (see Figure 4.37) the large squares indicate the current foreground and background colors (represented by their

relative positions) For painting, think of the foreground color as the color you’ll

actu-ally be painting with and the background color as an alternative color you have quick

access to when you need it if you want to change either of the colors, simply click the

corresponding box to open the Color Picker dialog box (shown in Figure 4.38) Click

(or click and drag) the vertical color bar to define the basic color you want, click the

large area to select a specific color to paint with, and then click oK

Figure 4.37 The Color Picker area on the

Tools panel shows you the current status

of your foreground and background colors

Figure 4.38 The Color Picker dialog box allows

you to select a specific color value to use

to set the colors back to the default values of black and white, click the smaller thumbnail at the bottom-left corner of the color swatches on the tools panel You can also set these defaults by pressing d on your keyboard

since the foreground and background color options are mostly a way to have two colors readily available when working with the Brush tool, you often want to

be able to switch back and forth between them at the top-right corner of the color swatches is a double-headed curved arrow Click this icon to switch the foreground and background colors, or perform the same action by pressing X

the options bar contains several settings that allow you to modify the behav-ior of the Brush tool (see Figure 4.39) near the far left is a Brush Preset drop-down list where you can select the type of brush you’d like to use Figure 4.40 shows the available Brush Preset options (if your view looks different, click on the fly-out menu and choose stroke thumbnail.) the size setting controls the size of the brush you’re using in pixels it’s much more effective to adjust the size of the brush based

on its relative size in your image, so we’ll set the size in a moment the Hardness set-ting determines whether your brush will have a hard edge, a soft and “fuzzy” edge,

or somewhere in between We’ll discuss specific settings for various situations in later chapters, but for now experiment with different settings to get a sense of how this set-ting affects the brush

Figure 4.39 The Options bar for the Brush tool contains several settings that allow

you to adjust the behavior of this tool

Figure 4.40 The Brush drop-down list

contains several settings for adjusting the type

of brush you’ll use to paint

at the bottom of the Brush Preset drop-down list is a scrollable list containing

a variety of brush shapes at the beginning are regular hard and soft brushes of

vari-ous sizes, followed by numervari-ous different-shaped tips that are of more use to graphic

artists Keep the different-shaped tips in mind in case you want to work creatively, but

normally you’ll be using a basic hard or soft brush

Note: You can also access the options from the Brush drop-down list by right-clicking/Ctrl- clicking

once you’ve set the basic properties of the brush, adjust the remaining settings

on the options bar the Mode drop-down list allows you to adjust the blending mode

for the brush, which affects how the “paint” you are drawing with interacts with the

underlying image We recommend leaving this set to normal We’ll tell you under

what circumstances you might need to change blending modes in later chapters

the opacity setting controls how opaque or transparent the paint you’re draw-ing with appears at full opacity, the paint completely covers the underlydraw-ing pixels,

effectively replacing them at a reduced opacity, the underlying pixels show through

(Figure 4.41 illustrates these situations using both hard and soft brushes set to the

same diameter.) We’ll use the opacity setting to vary the strength of the painting in

several adjustments we’ll discuss in later chapters, but for now play with various

set-tings to get a sense of how they affect the behavior of the Brush tool

Figure 4.41 The Opacity setting allows you to determine whether your paint strokes completely

cover up the pixels below them or allow them to partially show through

Brush tool, causing it to behave like an airbrush or a can of spray paint, where the

longer you hover over an area, the more the paint spreads out Because this creates a

somewhat unpredictable response from the Brush tool, we recommend leaving the

other settings for the pen and causes pen pressure to alter brush size We do not find this helpful for most photographic work

You’re just about ready to take the Brush tool for a test-drive, but you still need

to adjust the size of the brush Place the cursor on the new document you created, and evaluate the size of the brush then, press the left and right square bracket keys ([

and ]) to reduce or enlarge the size of the brush, respectively You can hold down the shift key while pressing the right and left bracket keys to adjust the hardness/softness, respectively, of the brush, but this isn’t quite as visual as the size adjustment For that reason we usually set the hardness/softness directly in the Brush panel

Cs5 also gives you the option to drag and modify the brush tip to resize the brush tip in Windows, press alt and right-click while dragging the cursor on a Mac, press option+Ctrl and drag to modify the softness/hardness of the brush in Win-dows, press alt+Ctrl and right-click while dragging unfortunately there does not seem to be a comparable Mac shortcut

Note: To draw a horizontal or perpendicular straight line, hold down the Shift key and then click and drag the cursor

Note: The Caps Lock key toggles the mouse-pointer display between Precise and the brush size settings If you’re not able to see the circle that defines the shape of your brush, check the status of Caps Lock This is one of the most common problems we encounter in workshops!

Brush Panel

the Brush panel is located on the tool options bar when you select a Brush tool, and

is accessible as a panel as well Clicking the icon opens the Brush panel in a float-ing dialog box You can select preset brushes and set the same parameters you set in the Brush Preset Picker on the options bar, but in addition you can modify brush tip options Most of these options are more useful to graphic artists than to nature pho-tographers, but if you use a graphics tablet such as a Wacom, you’ll need to use this dialog box to set the brush so that the opacity of your stroke varies with pen pressure

this will be useful when you’re painting on layer masks (We’ll be doing that exten-sively in later chapters.)

to vary the opacity of your brush stroke according to the pressure applied with your stylus, follow these steps: