128. Restore Quality to a Scanned Photograph See Also  6 Import a Scanned Image
60 Change Image Size or Resolution 124 Remove Specks and Spots 137 Improve Brightness and Contrast 149 Sharpen an Image
Sometimes an image doesn't require a lot of restoration. There are no holes, scratches, big dust spots, or faded colors. It just lacks the sharpness and snap that make you want to look at it again. If the original photograph contained sharp edges and high-quality color, these subtle qualities sometimes can be lost when you scan the picture. To improve your chances of getting a good scan, you might want to scan at double the resolution you're going to need for printing600 DPI. After making the adjustments shown in this task, you can resize the image downward as a last step, a process that increases the quality of the scan by making the pixels in an image even smaller. The worst type of photo to scan is a halftone photograph common to newspapers. In fact, scanning any type of printed material often results in a poor-quality digital image. If your scanner has a Descreen option, turn it on when scanning such photos; it can help remove the moiré pattern that often occurs. KEY TERM  | Moiré pattern The optical illusion that occurs when one regular geometric patternsuch as a grid made up of dotsoverlays another or similar pattern, when placed slightly askew. For example, two window screens placed on top of each other at an angle form a moiré effect. |
1. | Remove Moir° Pattern and Noise
Open an image in the Editor in Standard Edit mode and save it in Photoshop (*.psd) format. If your scan is of a halftone image, it might have moiré. Even if a scan is of a regular photograph, the scanning process might have introduced some noise that's more easily seen when the image is zoomed in.
TIP  | For persistent noise, you might have to blur the image while preserving the edge contrast (sharpness). See 150 Blur an Image to Remove Noise. |
In 124 Remove Specks and Spots, you learned how to remove noise from an image. You can start with the Despeckle filter by choosing Filter, Noise, Despeckle from the menu. If the noise persists, try the Median filter by choosing Filter, Noise, Median. In the Median dialog box that appears, adjust the Radius until the noise is removed. Because it combines the best of both filters, the Reduce Noise filter is often a very good choice: choose Filter, Noise, Reduce Noise. Adjust the Strength, Preserve Details, and Reduce Color Noise values as needed to remove the noise, and then click OK.
 | 2. | Adjust the Contrast
Next, you should improve the scan's contrast and tone. There are various ways you can do that, but the easiest method is to use Brightness/Contrast, described in 137 Improve Brightness and Contrast. Select Enhance, Adjust Lighting, Brightness/Contrast. The Brightness/Contrast dialog box appears. Drag the Brightness or Contrast slider to the right to increase it, or to the left to decrease it. When you're satisfied, click OK.
| 3. | Sharpen the Image
NOTES  | The techniques illustrated in 127 Restore Color and Tone to an Old Photograph might also help restore contrast and saturation to your scan. One way to quickly improve contrast in a dark scan is to apply the Equalize filter. Choose Filter, Adjustments, Equalize from the menu. The filter works automatically to create an even distribution of light and dark pixels throughout the image. |
When making multiple changes to an image, it's generally recommended that you not do any sharpening until the final step because sharpening is really a process that adjusts the contrast between pixels. If you sharpen too early in the process, other changes you make can sometimes undo the effects of sharpening. The best tool for sharpening an image is the Unsharp Mask, explained in detail in 149 Sharpen an Image.
After performing any other repairs you want to perform on the imagesuch as removing creases, tears, specks, and such (see 122 About Removing Scratches, Specks, and Holes)select Filter, Sharpen, Unsharp Mask from the menu bar. The Unsharp Mask dialog box opens. Adjust the Radius to set the size of the area around each pixel to be examined for contrast, and set the Threshold to a value that tells the filter what level of contrast must exist before a pixel is changed. Finally, set the Amount to the amount of contrast by which you want to increase qualifying pixels. When you're happy with the results, click OK.
| 4. | Reduce Resolution and Resample
If you scanned the image at 600 DPI or higher, you can reduce the resolution without changing the image's print size, a process that will cause the Editor to pack the pixels closer together, creating a denser, more detailed image.
First, save the PSD file. Then resave the file in JPEG or TIFF format, leaving your PSD image with its layers (if any) intact so that you can return at a later time and make different adjustments if you want. Starting with a JPEG or TIFF speeds up the process of resampling, while preserving the resolution of your original scan.
Choose Image, Resize, Image Size from the menu. The Image Size dialog box appears. Enable the Constrain Proportions option, and type a value that's half the image's current resolution in the Resolution box. Select the type of resampling you want to use from the Resample image list and click OK. See 60 Change Image Size or Resolution.
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