Datasheet

Welcome to Adobe Photoshop CS4

Part I

You can be confident that images for print will have enough resolution if they are scanned at

300ppi resolution or larger than their final printed size in inches. Images for on-screen display

need to have 72ppi resolution at their final size in pixels. Web pages are often constrained to an

800 wide x 600 tall pixel area, so that should give you some idea of the pixel dimensions your

images for the Web need to be. If in doubt, scan at a larger size. In Photoshop, enlarging image size

comes with a much greater risk of loss of detail than reducing it.

If you scan images from printed publications, an undesirable moiré pattern will likely be included

in the image because images printed in publications are made up of dots rather than continuous

tone. You can attempt to avoid or reduce moiré patterns by using a blur option in your scanner

software or by raising the image off the scanner bed slightly before you scan it (by mounting it on

a firm substrate and placing it on top of coins, for example).

Images that are mostly gray can benefit from being scanned in RGB color mode. You have more

initial information to work with in Photoshop, which can be useful even if you plan to convert the

image to Grayscale mode. Many scanners also let you choose the color profile. Adobe RGB is a

good color profile to use for scanning because it contains a relatively large amount of colors. You

can convert the image to another color mode in Photoshop, if necessary.

Be sure to make a note of where you’ve told your scanner to save the scanned image on your com-

puter. Then use Bridge or choose File ➪ Open from within Photoshop to open the files on your

hard drive into Photoshop.

The Internet

You can save images from Web pages to your computer by right-clicking on the image or image

link and choosing Save Image As or Save Linked File As. If you don’t have a mouse with a right-

click or you are using a Mac, Ctrl+click to get the same context menu.

Images on the Web are low resolution, usually 72 ppi, so keep in mind resolution requirements for

the purpose of your image.

If you are using Stock Art services, such as iStockPhoto, or photo collection sites, such as Flickr,

there may be different sizes and resolutions available.

E-mail

Like images from Web pages, you can save many images or image attachments in e-mails to your

computer by right-clicking on the image or image link and choosing Save Image As or Save Linked

File As. If you don’t have a mouse with a right-click or you are using a Mac, Ctrl+click to get the

same context menu.