Datasheet

Chapter 4: Digital Image Basics

Microsoft Digital Image Standard User’s Manual

Image Formatting

When you have a picture open on the canvas, there are a number of ways to

re-size or re-orient it.

Changing picture size

When you open an image onto the canvas, the on-screen representation of the

image is automatically sized so that it ﬁlls the workspace. As a result, a high

resolution image, such as 1600 x 1200 pixels, will appear onscreen just the

same size as a low resolution image that’s only 640 x 480 pixels. For this rea

son, viewing a picture on the canvas is not a reliable way of judging an image’s

actual resolution.

Whenever you resize an image, consider these three factors:

• Image size, which is the size of the printed image.

• Pixel dimensions, which is how many colored dots (pixels) make

up the picture.

• Resolution, which is the density of the pixels in the picture.

The image size is the product of the pixel dimensions multiplied by the resolu-

tion. For example, if you have a picture made of 1200 x 1800 pixels and print it

at a resolution of 300 pixels per inch, it will print at a size of 4" x 6". Given this

relationship, if you change one of the three settings, one of the other settings

will also have to change to keep the relationship equal. If you enlarged the

picture in the previous example from 4" x 6" to 8" x 12"—and you kept the

pixel dimensions the same—then the resolution would decrease from 300 pixels

per inch to 150 pixels per inch.

When you resize a picture, it is generally not a good idea to try to increase or

decrease the pixel dimensions since this reduces image quality. In most cases,

it’s not necessary to adjust the image size, since that can be handled automati

cally during printing. For high-quality prints, it’s generally good to keep the

picture’s resolution at least 300 pixels per inch. But depending on you printer

model and the image quality you desire, you may be satisﬁed with prints at

only 150 pixels per inch. For Web use, 72 pixels per inch is usually considered

sufﬁcient.