Photoshop cs5 by steve Johnson part 25 potx

ptg 156 Chapter 7 The Lens Correction filter fixes flaws that occur during the shooting of images, such as geometric distortion, vignetting, and chromatic aberra- tion. Geometric distortion causes straight lines to bow out toward the edges of the image. Vignetting is a defect where edges of an image are darker than the center. Chromatic aberration appears as a fringe of color along the edges of objects caused by the lens focusing on different col- ors of light in different planes. You can select options to automatically correct image problems or apply a Lens Correction Profile (LCP) for a camera (New!). If a profile for your camera is not available, you can search online or use Adobe Lens Profile Creator (New!) (available at www.labs.adobe.com ) to create one. If you know how you want to fix a problem, you can also manually adjust options to correct it (New!). Working with the Lens Correction Filter Use the Lens Correction Filter Open an image. Click the Filter menu, and then click Lens Correction. Select from the following tools: ◆ Remove Distortion Tool. Drag in the grid left or right to remove geometric distortion. ◆ Straighten Tool. Drag in the grid to draw a new horizon line (image shifts to the horizon). ◆ Move Grid Tool. Drag to reposition the visible grid. ◆ Hand Tool. Drag to move the image within the view window. ◆ Zoom Tool. Click in the view window to zoom in, or Alt+click (Win) or Option+click (Mac) to zoom out. Select from the following options on the Auto Correction tab (New!): ◆ Correction. Select to correct Geometric Distortion, Chromatic Aberration, or Vignette (New!). ◆ Edge. Select to fill in transparent areas of the image with the Black or White Color (New!), Edge Extension, or Transparent. ◆ Search Criteria and Lens Profile. Search for and select a lens profile to correct an image based on a camera and lens, or click Search Online (New!). 4 3 2 1 3 4 From the Library of Wow! eBook ptg Chapter 7 Working with Adjustment Layers, Filters, and Tools 157 Click the Custom tab. Select from the following tools: ◆ Settings. Choose from Lens Default, Previous Correction, Custom, or Default Correction. ◆ Remove Distortion. Drag the slider left or right to precisely remove pincushion or barrel distortion. Change the Chromatic Aberration options: drag left or right to remove Red/Cyan Fringe, Green/Magenta Fringe (New!), or Blue/ Yellow Fringe from the image. Select from the following Vignette options: ◆ Amount. Drag left or right to create a light or dark vignette around the image. ◆ Midpoint. Drag left or right to select the midpoint for the vignette. Select from the following Transform options: ◆ Vertical Perspective. Drag left or right to change the image's vertical perspective. ◆ Horizontal Perspective. Drag left or right to change the image's horizontal perspective. ◆ Angle. Drag the angle option to rotate the image clockwise or counter clockwise. ◆ Scale. Drag left or right to change the scale (size) of the image. Select the Preview check box to view changes as they are made. Select the Show Grid check box to view or hide (default (New!)) the grid. Click the Size list arrow to change the size of the grid boxes (default is 64 (New!)). Click the Color box to change the color of the grid. Click OK. 14 13 12 11 10 9 8 7 6 5 6 7 9 8 10 11 12 13 14 5 From the Library of Wow! eBook ptg 158 Chapter 7 Photoshop provides a variety of filters to blur the look of an image, including Box, Surface, and Shape. The Box Blur filter blurs an image based on the average color value of neighboring pixels. Its primary function is the creation of special effects. You can adjust the size of the area used to calculate the average value for a given pixel; a larger radius results in more blurring. The Surface Blur filter blurs an image while saving the visible edges; this filter is useful for creating special effects or removing that pesky noise or grain. The Radius option speci- fies the size of the area sampled for the blur. The Threshold option con- trols how much the tonal values of neighboring pixels must diverge from the center pixel value before being part of the blur. Pixels with tonal value differences less than the Threshold value are excluded from the blur. The Shape Blur filter uses a specified shape to create the blur. Choose a kernel from the list of custom shape presets, and use the radius slider to adjust its size. You can load different shape libraries by clicking the triangle and choosing from the list. Radius determines the size of the shape; the larger the shape, the greater the blur. Using the Box, Surface, and Shape Blur Filters Use the Box Blur Filter Open an image. Click the Filter menu, point to Blur, and then click Box Blur. Drag the Radius slider left or right to decrease or increase the amount of blur applied to the image. Click OK. 4 3 2 1 4 3 Results of Box Blur 1 From the Library of Wow! eBook ptg Chapter 7 Working with Adjustment Layers, Filters, and Tools 159 Results of Shape Blur Use the Surface Blur Filter Open an image. Click the Filter menu, point to Blur, and then click Surface Blur. Drag the Radius slider left or right to decrease or increase the amount of blur applied to the image. Drag the Threshold slider left or right to decrease or increase the acceptance of the shift in brightness of the image information (the edges). Click OK. Use the Shape Blur Filter Open an image. Click the Filter menu, point to Blur, and then click Shape Blur. Select a shape (called a kernel) from the available options. Drag the Radius slider left or right to decrease or increase the amount of blur applied to the image. Click OK. 5 4 3 2 1 5 4 3 2 1 1 1 Results of Surface Blur 5 5 4 3 4 3 From the Library of Wow! eBook ptg 160 Chapter 7 Using the Gaussian Blur and Despeckle Filters Use the Gaussian Blur Filter Select the portions of the image you want to blur or leave the image unselected to apply the filter to the entire image. Click the Filter menu, point to Blur, and then click Gaussian Blur. Select the Preview check box to view the results. Drag the Radius slider or enter a pixel value to increase or decrease the amount of Gaussian blur applied to the image. Click OK. Use the Despeckle Filter Select the Layers panel. Select the layer to which you want to apply the Despeckle filter. Click the Filter menu, point to Noise, and then click Despeckle. Photoshop applies the Despeckle filter to the image. 3 2 1 5 4 3 2 1 You can also apply the Gaussian Blur filter that blurs an image or a selection by a controllable amount. While not strictly a restoration tool, the Gaussian Blur filter can be used to add a sense of depth to the image. For example, you could select and blur the background of an image while leaving the foreground in focus. The outcome of the filter is to create a hazy, out-of-focus effect on the image or selection. Another filter, the Despeckle filter, detects the edges in an image and blurs the entire image except those edges. Of course, there are no real edges in a Photoshop document—the Despeckle filter works along areas where there is a significant shift in the brightness of the pixels. Since a shift in brightness usually signifies an edge, the Despeckle filter performs a very accurate blurring of the image while preserving detail. 5 3 Area to despeckle 1 4 2 From the Library of Wow! eBook ptg Chapter 7 Working with Adjustment Layers, Filters, and Tools 161 The Unsharp Mask filter creates a visually sharper image by locating pixels that differ in value from surrounding pixels. When the filter is applied to the image, the bordering pixels specified by the threshold option get lighter and the darker pixels get darker. It's important to understand that the Unsharp Mask does not actually sharpen the image; it only attempts to create the illusion of sharpness. Be careful; an over-application of this filter creates harsh images with ragged edges and shadows. Also, the effects of the Unsharp Mask filter appear more severe when viewed with the low resolution of a com- puter than when the document is output to a printer. Using the Unsharp Mask Filter Use the Unsharp Mask Filter Select the Layers panel. Select the layer you want to sharpen. Click the Filter menu, point to Sharpen, and then click Unsharp Mask. Select from the following options: ◆ Preview. Select the option to view changes to the image directly in the active document window. ◆ Amount. Drag the slider or enter a value to determine how much to increase the contrast of pixels. ◆ Radius. Drag the slider or enter a value to determine the number of pixels surrounding the edge pixels that affect the sharpening. ◆ Threshold. Drag the slider or enter a value to determine how different the sharpened pixels must be from the surrounding area before they are considered edge pixels and sharpened by the filter. Click OK. 5 4 3 2 1 4 5 The Unsharp Mask filter applied to the image. From the Library of Wow! eBook ptg 162 Chapter 7 The Smart Sharpen filter attempts to sharpen the pixels of an out-of- focus image in much the same way as the Unsharp Mask filter. The major difference is the ability of Smart Sharpen to remove previously applied Gaussian, Lens, and Motion Blur filters. For example, you've applied the Lens Blur filter to an image, but later decide to reduce the effect. The problem is that Unsharp Mask will attempt to sharpen what it assumes to be an out-of-focus image. Unfortunately, an image taken with an out-of-focus lens, and a Lens blur are two different things, and that's where the Smart Sharpen filter comes to the rescue. Using the Smart Sharpen Filter Use the Smart Sharpen Filter Select the Layers panel. Select the layer you want to sharpen. Click the Filter menu, point to Sharpen, and then click Smart Sharpen. Select the Preview check box to view the results. Select the Basic or Advanced option. Click the Settings list arrow, and then select from a list of user- defined settings. Select from the following Sharpen options: ◆ Amount. Drag the slider to determine the amount of sharpness applied to the image. ◆ Radius. Drag the slider to determine the width of the sharpening effect. ◆ Remove. Click the list arrow and then select what type of blur effect you are removing from the image. ◆ Angle. Enter the angle of the Motion Blur filter to remove. ◆ More Accurate. Select for a more accurate (slower) sharpening effect. 7 6 5 4 3 2 1 4 5 6 7 Original image From the Library of Wow! eBook ptg Chapter 7 Working with Adjustment Layers, Filters, and Tools 163 Select the Shadow panel and then select from the following Shadow options: ◆ Fade Amount. Drag the slider to determine the amount of shadow correction applied to the image. ◆ Tonal Width. Drag the slider to set the width of the tonal values in the image shadows. ◆ Radius. Drag the slider to choose the scale size for the shadows. Select the Highlight panel, and then select from the following Highlight options: ◆ Fade Amount. Drag the slider to determine the amount of highlight correction applied to the image. ◆ Tonal Width. Drag the slider to set the width of the tonal values in the image highlights. ◆ Radius. Drag the slider to choose the scale size for the highlights. To save a copy of the current Smart Sharpen settings, click the Save button. To delete the active saved Sm ar t Sharpen settings, click the Delete button. Click OK. 12 11 10 9 8 12 10 11 8 Image using Smart Sharpen From the Library of Wow! eBook . then click Despeckle. Photoshop applies the Despeckle filter to the image. 3 2 1 5 4 3 2 1 You can also apply the Gaussian Blur filter that blurs an image or a selection by a controllable amount creates a visually sharper image by locating pixels that differ in value from surrounding pixels. When the filter is applied to the image, the bordering pixels specified by the threshold option get. much the tonal values of neighboring pixels must diverge from the center pixel value before being part of the blur. Pixels with tonal value differences less than the Threshold value are excluded