Adobe 29180155 - Photoshop Elements 4.0 Tutorial page 101

Resample an image
Changing the pixel dimensions of an image is called resampling. Resampling affects not only the size of an image onscreen, but also its image
quality and its printed output—either its printed dimensions or its image resolution. Resampling can degrade image quality. When you downsample,
meaning that you decrease the number of pixels in your image, information is removed from the image. When you upsample, or increase the
number of pixels in your image, new pixels are added based on the color values of existing pixels, and the image loses some detail and
sharpness.
To avoid the need for upsampling, scan or create the image at the resolution required for your printer or output device. If you want to preview the
effects of changing pixel dimensions onscreen or print proofs at different resolutions, resample a duplicate of your file.
Resampling an image
A. Image downsampled B. Original image C. Image upsampled
If you're preparing images for the web, it's useful to specify image size in terms of the pixel dimensions.
1. Choose Image > Resize > Image Size.
2. Select Resample Image, and choose an interpolation method:
Nearest Neighbor Fast, but less precise. This method is recommended for use with illustrations containing edges that are
not anti-aliased, to preserve hard edges and produce a smaller file. However, this method can create jagged edges, which
become apparent when distorting or scaling an image or performing multiple manipulations on a selection.
Bilinear Medium-quality.
Bicubic Slow, but more precise, resulting in the smoothest tonal gradations.
Bicubic Smoother Use when you're enlarging images.
Bicubic Sharper Use when you're reducing the size of an image. This method maintains the detail in a resampled image. It
may, however, oversharpen some areas of an image. In this case, try using Bicubic.
3. To maintain the current aspect ratio, select Constrain Proportions. This option automatically updates the width as you change
the height, and vice versa.
4. In Pixel Dimensions, enter values for Width and Height. To enter values as percentages of the current dimensions, choose
Percent as the unit of measurement.
The new file size of the image appears next to Pixel Dimensions, with the old file size in parentheses.
5. Click OK to change the pixel dimensions and resample the image.
For best results in producing a smaller image, downsample and apply the Unsharp Mask (Enhance > Unsharp Mask). To
produce a larger image, rescan the image at a higher resolution.
Keywords: cropping, image size, image resolution, retouching, sharpening, transforming, 3D transform, rotate, skew, scale, Unsharp Mask,
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