Photoshop cs5 cho nhiếp ảnh gia part 43 pptx

then click and drag on the image to create a gradient: the foreground color starts where you first click, with a smooth gradation to the background color where you release the mouse, as

Tr y It! To start getting more comfortable with Curves, open the image Curves at www.sybex com/go/photoshopnature and make some adjustments, starting with a simple S curve adjust-ment and then working to fine-tune the overall tonality to your liking

Creating a Virtual Split Neutral-Density Filter

Another tool that you can use to create a layer mask is the gradient tool this allows

you to place a gradient on the mask, resulting in an adjustment that affects one side of

the image completely but gradually tapers off in a given direction until it has no effect

at the other side of the image the most common example of using such a gradient

is in a composition where you would otherwise shoot with a graduated split

density filter, such as when you need to darken the sky without darkening the

fore-ground of an image You can use the gradient tool in ACr to create a similar effect,

but the advantage of doing it in photoshop is that you can customize the filter to the

exact size and shape you need

to create a virtual split neutral-density filter, follow these steps:

area of the image to which you want it to apply For example, you may create a levels (or Curves) adjustment layer that darkens the sky in an image by moving the midtones slider to the right After you’ve made the adjustment, click ok in the dialog box for the adjustment to apply the settings on the layer

the options bar, click the drop-down list for the gradient editor, and choose the first gradient thumbnail on the list, which is the Foreground to Background gradient next, select the linear option for the gradient tool on the options bar (shown in Figure 6.29), which is the first in the set of five buttons allowing you to choose a style for your gradient

Figure 6.29 To use a gradient on a layer mask, select the Foreground to Background gradient with the

Linear option from the Options bar

foreground color (pressing x to switch foreground and background colors if necessary) You’re now ready to create a gradient that transitions from white to black

just created, so make sure that is the active layer in the layers panel then click and drag on the image to create a gradient: the foreground color starts where you first click, with a smooth gradation to the background color where you release the mouse, as shown in Figure 6.30 the length of the line you drag determines the distance over which the gradient transitions, and the direction

determines the angle of that gradient to lock the gradient to 45° increments, simply hold the shift key as you drag

Figure 6.30 Draw the gradient on the

layer mask so the adjustment tapers from adjusted to nonadjusted areas

lowest area you still want the adjustment to affect completely, and drag down-ward to the point where you don’t want any effect at all You don’t need to drag across the entire image—just the area where the transition should occur

if you’re not happy with the initial gradient you created, simply click and drag again to replace the gradient with a new one the result is an adjustment that blends smoothly, from applying completely in one area of the image to having

no effect on another area (see Figure 6.31)

Figure 6.31 By applying a gradient mask to the adjustment, you’re able to produce

an adjustment that gradually blends, as with the darkened sky in this example

if your image requires an odd shape to the split neutral-density filter, you can modify the layer mask by painting on it to add or remove the effects where necessary

this can be useful when shooting in the mountains where the sky may be very light

but the mountains dark, and the sky area may be v-shaped

Safe Dodge and Burn Layers

dodging and burning are techniques borrowed from the wet darkroom, where you

can use your hands or various instruments to block light from specific areas of an

image the longer the light from the enlarger strikes any given area, the darker that

area will be Blocking light to small areas during exposure is referred to as dodging

and results in the blocked areas being lighter in a print than they otherwise would

have been Burning is the opposite: blocking light from most of the image so you can

concentrate light for a portion of the exposure on one particular area, darkening that

area of the print

in photoshop you can produce similar effects in fact, photoshop includes

them because you must apply them directly to an image layer, and they don’t offer the

flexibility of the method we’ll present here however, an advantage they offer is that

you can set them to affect only the shadows, midtones, or highlights if you opt to

use these tools, do so on a copy of the Background layer then set the tonal range on

the tool options bar and check the option to protect tones reduce the exposure to

about 10–15% as a starting place When you release the cursor and go over an area

again, the effect is cumulative, so you can gradually build up the amount of dodging

or burning for a nicely controlled result

Setting Up

the method we recommend for dodging and burning uses one layer for dodging and

another for burning, and takes advantage of layer masks and layer blending modes

Blending modes are different ways of combining layers so far all the layers we’ve worked

with in the examples have been in normal mode, but photoshop contains numerous

algo-rithms for different ways to combine two layers You can combine layers so that the tonal

values are added together or multiplied, or the darker value used, or the lighter values,

and so on You don’t have to become an expert on each of the algorithms; we’ll use

just two of them here: screen and multiply We’ll talk more about blending modes in

Chapter 9, “Creative Effects.”

Note: We prefer this method to the older Overlay method because it’s more forgiving and easier

to use

Although setting up the dodging and burning requires a lot of steps, the procedure

is easy and can be automated by creating an action (see Chapter 11, “time-savers”)

to set up layers to use for dodging and burning, do the following:

Dodge.

shown in Figure 6.32 the entire image will become one full stop lighter, which

in most images means that it will instantly be overexposed don’t worry—we’re not going to leave it that way for long!

Figure 6.32 Take advantage of blending modes

to create dodge and burn layers that can be modified easily

should now be black, and your image should look the way it did before we began setting up for dodging and burning

keyboard Be sure to use a soft-edged brush, as shown in Figure 6.33

Figure 6.33 Use a soft-edged brush when dodging and burning your image

with this method

you proceed since it controls the strength of the dodging and burning

Note: It’s important to set the brush to the Normal blending mode in the tool Options bar, while the layer itself is set to Multiply or Screen in the Layers panel

Note: If you’re using a tablet, you can also use pen pressure of the stylus to determine the Opacity setting when dodging and burning with this method

of black foreground and white background note that you can switch the fore-ground and backfore-ground colors by pressing x as you’re working, allowing you

to easily switch between black and white

now you’re ready to apply selective lightening and darkening to the image

Painting with Light

With your new layers and the Brush tool properly configured, you’re ready to start painting with light paint with white using the brush at a reduced opacity on the appropriate layer to lighten or darken your image Although it appears that you’re painting directly on your image, you’re actually painting on the layer mask Because you’re painting at a reduced opacity, the result is relatively modest if necessary, you can paint over areas multiple times to build up an effect the best effect is usually subtle When people look at the final image, they shouldn’t get the impression that you were using dodging and burning techniques however, when you toggle the vis-ibility of the dodge and burn layer off and on, you’ll see a difference between the images

it’s important to understand the behavior of the Brush tool when you’re work-ing at a reduced opacity for this technique As long as you hold down the mouse but-ton, the effect does not accumulate no matter how many times the mouse passes over

a particular area however, if you release the mouse and start painting again, the effect is uneven if you partially overlap areas you’ve previously painted therefore, it’s important that you click and hold the mouse button while painting until you’ve covered the entire area you want to adjust then release the mouse and start painting again in additional areas you’d like to change

dodging and burning are two of our favorite techniques in photoshop We appreciate the capability to paint with light, bringing out details in various areas of the image or simply emphasizing particular features (see Figure 6.34)

Dodge.

shown in Figure 6.32 the entire image will become one full stop lighter, which

in most images means that it will instantly be overexposed don’t worry—we’re

not going to leave it that way for long!

should now be black, and your image should look the way it did before we

began setting up for dodging and burning

keyboard Be sure to use a soft-edged brush, as shown in Figure 6.33

Figure 6.33 Use a soft-edged brush when dodging and burning your image

with this method

Figure 6.34 Dodging and burning allow you to enhance detail or add drama to various areas of your image with tremendous

flexibility, producing an image that has been adjusted in a subtle way but with a big difference in the final result

Correcting Mistakes

of course, now and then you may be less than satisfied with an adjustment you’ve made when using this technique Fortunately, because you apply it using a layer mask, it’s easy to fix mistakes even if it’s too late to simply undo a step on the history panel

there are two basic ways to correct your mistakes if you were painting with white as your foreground color, make black the foreground color, or vice versa, and

set the opacity to 100% paint over the problematic area, and begin again

Alternatively, if you are dissatisfied with all the dodging or burning you did,

start over

Tr y It! To practice dodging and burning, open the image DodgeBurn from www.sybex.com/

go/photoshopnature, and use the method presented here to add drama to the rock formation, enhancing texture and contrast

The Shadows/Highlights Adjustment

the shadows/highlights adjustment is an excellent way to reveal subtle detail in

the shadow and/or highlight areas of your images Although you could theoretically

produce similar results with sophisticated use of Curves, the shadows/highlights

adjustment is far easier to use when you need to recover detail that has been lost in

shadow or highlight areas because of excessive contrast it’s similar to the Fill light

and recovery sliders in ACr, which we covered in Chapter 3, but it has additional

controls so you can fine-tune the results

Note: Some photographers are tempted to try to use Shadows/Highlights to fix all their exposure problems We don’t recommend that because the Shadows/Highlights adjustment works by reducing contrast That’s fine for small tonal ranges, but it’s not usually a good idea to do throughout the entire image We find it’s far more effective to limit the Shadows/Highlights tool to recovering detail in the deep shadows and recovering highlights in very light areas

Although you can’t apply the shadows/highlights adjustment as an adjustment layer, you can use it as a smart Filter As we discussed in Chapter 5, “Workflows and

First steps,” a filter that’s applied as a smart Filter behaves similarly to an adjustment

layer the advantage of using it as a smart Filter is that you can tweak the settings

as needed, and you can add a layer mask to it to target the effects to certain areas of

your image For example, perhaps you have a portrait of a dark animal against a dark

background You may want to reveal details in the shadows of the animal but not in

the background

We recommend using the shadows/highlights adjustment early in your work-flow, as the first step after you open the raw file as a smart object to do so, take these

steps:

shadows/highlights as a smart Filter