Scanning

Scanning Images:

Place your image face down on the flatbed scanner.

Option 1:

Import an image through Photoshop using the TWAIN interface: (If more than one TWAIN device is installed in your system and you want to switch devices, use the Select Source command to choose the new device.)

Choose File > Import and choose TWAIN - Acquire (Macintosh) or the appropriate TWAIN command (Windows) to use the TWAIN interface.

Option 2:

Import an image through DeskScan II found under Applications.

Then:

Select Preview - The Preview button gives you a preliminary view of the image on your scanner. Previewing an image gives you greater flexibility, as it allows you to apply various controls to the preview image before actually scanning it in. With the preview image displayed, you can apply image enhancements or crop the image before performing the final scan.

We will be doing many image enhancements in Photoshop, but it nice to know that you can do many of them when you scan also. I feel that it is best to scan first and adjust the image later-that way you can always undo it. Feel free to crop out the extra screen to just have your image selected. You can do the final cropping in Photoshop- so be liberal (again, you canÕt undo if it is cropped too much while scanning-your only option then is to rescan).

Open Settings Window to change resolution and image size- For most projects it is best to scan the image to the size you want it end up. This becomes a big issue when file size becomes an issue-such as for web publishing. Make sure everything is set up to the specifications for your project.

Select Scan - The Scan button lets you scan the image in your scanner and delivers it to your image-editing software (Photoshop). The scanned image is based on the specifications you have chosen in the Settings window and on controls you may have applied to the preview image if a preview was performed.

Make sure that when the scan dialogue box comes up that you save the image to your file on the desktop, or to your zip disk.

When you scan an image, you make several choices that affect the quality and usefulness of the resulting file. Before you scan an image, be sure to follow the instructions in Determining the scan resolution, Optimizing the dynamic range of the scan, and Eliminating unwanted color casts.

Determining the Scan Resolution: Scan resolution, as it is used here, is the same as image resolution--that is, the number of pixels per inch in the image when you open the file in Adobe Photoshop. For information on resolution and pixel dimensions, see About resolution and image size from Photoshop Help Menu. The scan resolution you use for printed output depends on the quality of output that you need as well as on the resolution of your printer and the size of the original image compared with the final image. See Screen frequency and image resolution from Photoshop Help Menu for guidelines on choosing the best resolution for a printed image.

Optimizing the Dynamic Range of the Scan: When scanning an image, keep in mind that the human eye can detect a wider tonal range than can be printed. If your scanner lets you define the black and white points, set the points before scanning the file to produce the best tonal range and capture the widest dynamic range. After opening the file in Adobe Photoshop, use the color correction tools to set the white and black points for the digitized image. See Making Color and Tonal Adjustments from Photoshop Help Menu for more information about setting the black and white points for an image.

Eliminating Unwanted Color Casts: If your scanned image contains an unwanted color cast, you can perform a simple test to determine whether the cast has been introduced by your scanner. If you find that it has, you can use the same test file to create a color cast correction for all images scanned using that scanner.

To identify and correct a color cast introduced by a scanner:

1 Open a new Photoshop file and use the gradient tool to create a blend from pure black to pure white.

2 Choose Image > Adjust > Posterize and posterize the blend using 11 levels.

3 Print the 11-step gray wedge and then scan it into Photoshop.

4 Open the Info palette and read the RGB values on-screen for each of the gray levels. Uneven R, G, and B values indicate a color cast. See Choosing a Color Display Mode for more information on color and color values.

5 Use Levels to correct the color cast (see Making Color and Tonal Adjustments from Photoshop Help Menu for instructions), and then save the dialog box settings.

6 Open the scanned image you want to correct, reopen the Levels dialog box, and load the saved settings.