Tự học Photoshop

Choose Layer > New Adjustment Layer > Levels, and then click OK in the New Layer dialog box.. Adobe Photoshop gives you a simple way to fix red-eye using the Color Replacement tool.. Cre

Image correction made easy with the Levels command

Does your photo look dull, lacking contrast? Or, does it have a color cast? Is it reddish or greenish? Adobe Photoshop's Levels command lets you correct the tonal range and color balance of an image by adjusting intensity levels of the image's shadows, midtones, and highlights In this tutorial, you'll learn how to adjust the tonality and color in your images using the Levels command

1 Open an Image in Photoshop

Choose File > Open or double-click a thumbnail in the File Browser Before you start making adjustments, evaluate the image tonality Is it too light or dark? Does it have too much or too little contrast? Is there a color cast?

2 Create a new Levels adjustment layer

Choose Layer > New Adjustment Layer > Levels, and then click OK in the New Layer dialog box You can also open the Levels command by choosing Image > Adjustments > Levels However, with an adjustment layer, you are applying the tonal correction on a separate layer The original image is untouched If you decide you don't like your

changes, you can change them at any time or simply discard the adjustment layer and return to your original image

A useful tool for evaluating an image's tonality is the histogram displayed in the Levels dialog box A histogram illustrates how pixels in an image are distributed by graphing the number of pixels at each color intensity level This can show you whether the image contains enough detail in the shadows (shown in the left part of the histogram), midtones (shown in the middle), and highlights (shown in the right part) to create good overall contrast in the image

3 Set the shadows and highlights

Move the Black Point Input slider and the White Point Input slider (located directly beneath the histogram) inward from the edges of the histogram Moving the Black Point Input slider maps all image values at its position or below to the Output Levels black point (set by default to 0, or pure black) Moving the White Point Input slider maps image values at its position or above to the Output Levels white point (set by default to

255, or pure white)

For example, if your image is too dark, try moving the Input White Point slider to the left This maps more values in the image to 255 (the Output Levels white point), making them lighter

4 Adjust the midtones.

Move the middle Input slider to the left to lighten the image or to the right to darken the image

The middle Input slider adjusts the gamma in the image It moves the midtone (level 128) and changes the intensity values of the middle range of gray tones without dramatically altering the highlights and shadows

5 Remove the color cast

Select the Set Gray Point Eyedropper tool in the Levels dialog box Click an area in the image that contains only a gray tone, or an area containing as few colors as possible It's easier to color balance an image by first identifying an area that should be neutral and then removing the color cast from that area With such a correction, all other colors in the image should be color balanced, too The eyedropper tools work best on an image with easily identified neutrals

Advanced users often use the Levels command to adjust individual channels and remove

a color cast Choose a channel from the Channel menu of the Levels dialog box and then adjust the Input sliders

Remove red-eye in images

There's nothing more frustrating than having a great picture ruined when a person's eyes come out bright red Adobe Photoshop gives you a simple way to fix red-eye using the Color Replacement tool In this tutorial, you'll learn how to use the tool to fix red-eye in just a few steps

1 Open your image.

Open the image that you want to repair Try zooming in so you can easily see the red eyes that need to be fixed Then, select the Color Replacement tool (located in the

toolbox with the Healing Brush and Patch tool)

2 Choose a brush tip

Choose a brush tip from the options bar The brush tip should be smaller than the red area

of the eye to make correcting the red-eye easier

3 Set options for the Color Replacement tool

In the options bar, you can choose settings that help you fix red-eye For Mode, make sure that Color is selected For the Sampling option, choose Once to erase only areas containing the color that you target For the Limits option, select Discontiguous to replace the sampled color wherever it occurs under the brush Drag the Tolerance slider

to a low value (around 30 percent) to replace only the few colors very similar to the pixels you click

4 Choose a color to replace the red

Typically, black is a good choice, but you could try other colors to more closely resemble

a person's eye color To choose a color, click the foreground color swatch in the toolbox

In the color picker, choose a color that looks good, and then click OK

5 Repair your photo

Click once on the color you want to replace in the image Drag over the red with black to repair the image If all the red isn't removed, try increasing the Tolerance level in the options bar to correct more shades of red

Once you're happy with the correction, save your image Red-eye will never present a problem again!

Create an image using layers

When you build an image from different pieces background color, text, shapes, and photographs Adobe Photoshop layers give you complete creative control In this tutorial you'll create a multilayered image, apply a layer mask, and then add a text layer

1 Open an Image in Photoshop

Choose File > Open or double-click a thumbnail in the File Browser

By default, the Layers palette should show If not, choose Window > Layers The Layers palette displays all the layers in your document with the layer name and a thumbnail of the layer's image

2 Convert the background layer.

In the Layers palette, double-click the background layer Click OK in the New Layer dialog Converting the background into a regular layer lets you use transparency in this layer You can now view or hide the layer using the eye icon Click the eye icon on a layer Notice that the icon disappears and the layer is hidden Click the empty icon box again Both the eye icon and the layer's content reappear

3 Apply a layer mask

A layer mask lets you select and display just the part of the image you want to use, without altering the image Here we'll mask out all of the image except a circular area of the flower Click and hold the Rectangular Marquee tool, and then select the Elliptical Marquee tool from the pop-up menu Hold down the Shift key to constrain the selection

to a circle, and then drag an area on the image In the Layers palette, click the Add Layer Mask icon

Now only the area you selected is visible You can change the visible area by moving the mask around the image First click the link icon to unlink the mask from the layer Select the Move tool, and then click inside the mask and drag to reposition it Once you have

your final position, click the link icon to relink the mask and the layer Now you can move the layer and the mask will move with it

4 Add a stroke effect

Click the Add a Layer Style button at the bottom of the Layers palette, and select Stroke from the menu Choose stroke settings in the Layer Style dialog box, including color, size, and position of the stroke

5 Create a new layer

Click the Create a New Layer button to add a new layer to the image The new layer is added on top of existing layers and becomes the selected layer Click the Foreground color swatch and select a color with the Color Picker Select the Paint Bucket tool

(located in the toolbox with the Gradient tool) and click anywhere in the image to create the fill

6 Reorder the layers

Click the new layer and drag it beneath the lower layer Changing the stacking order of your layers makes certain parts of the image appear in front of or behind other layers

7 Add a text layer

In the Layers palette, click the top layer Select the Text tool, and then click on the image The text cursor appears In the options bar, change text size, font, style, or color to your liking.When you add text, Photoshop automatically places it on its own layer, where you can edit it separately from the rest of the image

To edit the text, select it with the Text tool, and then change any of the settings in the options bar To move the text, select the Move tool and then drag the text

8 Add an effect to the text.

Click the Add a Layer Style button and select Drop Shadow from the menu You can change the color or angle of the shadow or make other adjustments in the Layer Style dialog box

In the Layers palette, the layer effect shows under the layer name You can turn display

of the layer effect on or off by clicking the eye icon next to the effect

Using Photoshop selection tools

Having trouble deciding how to select part of your image? Adobe Photoshop gives you several tools that help you target just the areas you need to select In this tutorial, you'll

learn about the best way to use each of the selection tools.You can practice with the eagle image, located in the Photoshop CS/Samples folder

1 Use the Magic Wand tool to select the background of the image

Since the eagle in our image has a well-defined shape, and since the colors in the eagle are different than the green background, we can select it using the Magic Wand tool Select the Magic Wand tool, and then click anywhere in the green background The green area is surrounded by a marquee and is now editable Try dragging a paintbrush over the whole image to see how the eagle is protected

2 Invert your selection

Because our background was so easy to select, we'll invert the selection so that just the eagle is selected Choose Select > Inverse You'll see the selection border change

so that the eagle is surrounded This is an easy method to make a selection when you have an image like the eagle You could now work with the eagle without disturbing the background of the image For now, choose Select > Deselect so we can try out another tool

3 Use the Elliptical Marquee tool to select the eagle's eye.

Select the Elliptical Marquee tool, and then drag to draw a selection border around the eagle's eye To reposition the selection border while you're drawing it, hold the spacebar and drag the selection border into a new position To move the selection border after it's created, click anywhere inside the border and drag

4 Use the Magnetic Lasso to select the eagle's beak

Select the Magnetic Lasso tool (located in the toolbox with the Lasso tool), and then click and drag around the beak The Magnetic Lasso tool makes free-form selections easier because it traces around an object It works best when you have a clearly defined edge, like the eagle's beak The tool places anchors while you drag (you can remove anchors while you're dragging by pressing the Delete key) To finish the selection border, click the starting anchor point (or double-click) Try moving the beak using the Move tool Choose Edit > Undo to return the beak to its correct position Then choose Select > Deselect to deselect the beak

5 Add to a selection

Select the Marquee tool, and make a rough selection of the eagle's body Once you've made a selection, you can add to the selection border without having to start over Select the Magnetic Lasso tool, and click the Add to Selection icon in the options bar Refine

your selection by dragging around the outside of the eagle (you'll notice a small plus sign below the tool pointer) Release the mouse The selection border now includes the area you selected with the Magnetic Lasso tool

Produce great prints using Print with Preview

What's a great way to produce color prints from your inkjet printer? Use the Print with Preview command in Adobe Photoshop The Print with Preview command lets you preview how your photo will print so the results are more predictable You'll learn how to add a simple border around your photo and then transform it into a frame by adding a texture and layer style

1 Open the photo you want to print

Choose File > Open or double-click a thumbnail in the File Browser

You should do any retouching or tonal correction to your photo before printing it

2 Choose the Print with Preview command

Choose File > Print with Preview

The Print with Preview command lets you see a preview of how an image will print on a page and control how it will print The preview updates as you specify the position and scale of the image

3 Position the image.

Deselect the Center Image option so that you can enter Top and Left values to reposition the image You can also drag the preview image to the desired position If the page is not correctly oriented for the image, you can click the Page Setup button and select an orientation in the Page Setup dialog box

Don't specify a scaling percentage in the Page Setup dialog box Instead, use the scale controls in the Print dialog box Specifying the scaling in both the Page Setup dialog box and the Print dialog box will apply scaling twice, and your image will not print at the size you expect

4 Scale the image

You can scale the image in several ways Select the Scale to Fit Media option and

Photoshop automatically fits the image to the page You can also manually enter values for the Scale, Height and Width Or, you can grab one of the handles in the preview image and scale the photo

5 Set the color management options and click the Print button.

Select Show More Options Choose Color Management from the menu in the More Options area Select Document for the Source Space If you want Photoshop to handle color management during printing, choose your printer's profile from the Profile menu in the Print Space area If you prefer to let your printer's driver handle the color

management, then choose Printer Color Management from the Profile menu Click the Print button The Print dialog box closes, and a second Print dialog box opens

Color management is essential for producing consistent color when printing Whether you let Photoshop or your printer driver control color management, you'll get the best results using a custom profile for your printer and the specific type of paper you're printing on

6 Specify the printer settings

In the second Print dialog box, choose your printing options On Windows, click the Properties button, then the Advanced button, to access the printer driver options On Mac

OS, use the pop-up menu to access the printer driver options If you chose Printer Color Management in the previous step, specify the color management settings If you're letting

Photoshop control the color management, then make sure any color management options are turned off

Do not apply color management twice to your image Unpredictable print color will result if color management is done with both Photoshop and the printer driver

simultaneously

7 Print the image

Once all the settings have been made in the printer options dialog box, click the Print button

Using Photoshop shapes

Adobe Photoshop makes it easy to add shapes to an image: you can draw them using a variety of shape tools, or select from a large assortment of predrawn shapes You can arrange vector shapes on separate layers for easy modification and overlay effects In this tutorial, you'll add both background and foreground shapes to an image and create some flair with gradient and layer effects

1 Open an Image in Photoshop

Choose File > Open or double-click a thumbnail in the File browser For this tutorial, you might want to start with an image that has at least two layers First we'll add shapes to build a more interesting background for the image