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Canvas 12 User Guide - ACDSee

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Using TWAIN-compatible scanners<br />

Chapter 5: Painting And Image Editing<br />

Scanner manufacturers created the TWAIN interface to standardize interaction between scanners<br />

and computer software. Scanners that comply with the TWAIN standard provide a “source manager”<br />

file, which translates scanner information into data that <strong>Canvas</strong> can use. You must install the TWAIN<br />

scanner software on your system before you can select the scanner and scan images in <strong>Canvas</strong>.<br />

If you aren’t sure whether a scanner is TWAIN-compatible, consult the scanner documentation or<br />

contact the manufacturer.<br />

To select a TWAIN scanner:<br />

1. Choose Image | TWAIN Import | Select Scanner. In the Select Source dialog box, a scrolling<br />

list contains the names of all TWAIN scanners for which <strong>Canvas</strong> can locate a data source.<br />

2. Select the scanner you want to use and click OK. The Select Source dialog box closes and the<br />

scanner you selected becomes the active scanner.<br />

To acquire images using a TWAIN scanner:<br />

1. When you scan an image, it appears in the active <strong>Canvas</strong> document. Open an existing<br />

document or choose File | New to create a new document.<br />

2. Choose Image | TWAIN Import | Acquire Image.<br />

3. In the dialog box, select the options you want to use.<br />

Click Prescan to view a preview of the image. You can verify that the image is aligned and<br />

completely visible and reposition it if necessary.<br />

Depending on the available options, you can adjust scaling and brightness of the image.<br />

4. Click Scan to begin scanning. When the scanner finishes, the scanned image appears in the<br />

active <strong>Canvas</strong> document.<br />

Choosing a scanning resolution<br />

Digital images are composed of square pixels, and pixel size is a major factor affecting image quality.<br />

The resolution of an image is expressed as the number of pixels per (linear) inch (ppi), or pixels per<br />

centimeter. Smaller pixels result in higher image resolution, which generally indicates better image<br />

quality. With scanned images, the resolution is also a measure of how much information has been<br />

captured from the original artwork.<br />

At relatively low resolution, such as 75 ppi, lines, edges, and character shapes in an image can<br />

appear jagged (see "About digital images and resolution" on page 448).<br />

Use the following questions to help you decide an appropriate resolution when you scan images.<br />

447

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