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Changing the dimensions and resolution of bitmaps

After you add a bitmap to a drawing, you can change its dimensions and resolution.

Changing dimensions

You can change the physical dimensions of bitmaps by increasing or decreasing their height and width. When you increase the dimensions, the application inserts new pixels between existing pixels, and their colors are based on the colors of adjacent pixels. If you increase the dimensions of bitmaps significantly, bitmaps may appear stretched and pixelated.

The size of the bitmap on your screen depends on the pixel height and width of the bitmap, on the zoom level, and on your monitor settings. As a result, the size of the bitmap may appear different on your screen and in print.

Changing bitmap resolution

You can change the resolution of a bitmap to increase or decrease its file size. Resolution is measured by the number of dots per inch (dpi) when the bitmap is printed. The resolution you choose depends on how the bitmap is output. Typically, bitmaps created only for display on computer monitors are 96 or 72 dpi and bitmaps created for the Web are 72 dpi. Bitmaps created for printing on desktop printers are generally 150 dpi, while professionally printed bitmaps are usually 300 dpi, or higher.

Higher-resolution bitmaps contain smaller and more densely packed pixels than lower- resolution bitmaps. Upsampling increases the resolution of a bitmap by adding more pixels per unit of measure. Bitmap quality may be reduced because the new pixels are interpolated based on the colors of neighboring pixels; the original pixel information is simply spread out. You cannot use upsampling to create detail and subtle color gradations where none existed in the original image.

Downsampling decreases the resolution of a bitmap by removing a specific number of pixels per unit of measure. Best results are usually achieved when downsampling is done after color and tone corrections but before sharpening.

To change the dimensions of a bitmap Back to Top
1.
 
Select a bitmap.
2.
 
Click Bitmaps Resample.
3.
 
Choose a unit of measure from the list box next to the Width and Height boxes.
4.
 
Type values in any of the following boxes:
Width
Height
If you want to minimize the jagged appearance of curves, enable the Anti-alias check box.
If you want to maintain the file size, enable the Maintain original size check box. When this check box is enabled, the resolution of the bitmap is automatically adjusted as you change the image dimensions.
You can maintain the proportions of the bitmap by enabling the Maintain aspect ratio check box and typing a value in either the Width or Height box.
You can also resample the bitmap as a percentage of its original size by typing values in the Width % and Height % boxes.
To change the resolution of a bitmap Back to Top
1.
 
Select a bitmap.
2.
 
Click Bitmaps Resample.
3.
 
In the Resolution area, type values in any of the following boxes:
Horizontal
Vertical
If you want to maintain the proportions of the bitmap, enable the Maintain aspect ratio check box.
If you want to maintain the file size, enable the Maintain original size check box. When this check box is enabled, the height and width of the bitmap are automatically adjusted as you change the resolution.
You can also resample a selected bitmap by clicking the Resample button on the property bar.
Enable the Anti-alias check box to minimize the jagged appearance of curves.

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