Improving performance with filters

Some filter effects can be memory intensive, especially when applied to a high-resolution image. You can use these techniques to improve performance:

• Try out filters and settings on a small portion of an image.
• Apply the effect to individual channels--for example, to each RGB channel--if the image is large and you're having problems with insufficient memory. (With some filters, effects vary if applied to the individual channel rather than the composite channel, especially if the filter randomly modifies pixels.)
• Free up memory before running the filter by using the Purge command. (See Correcting mistakes.)
• Allocate more RAM to Photoshop. If necessary, exit from other applications to make more memory available to Photoshop.
• Try changing settings to improve the speed of memory-intensive filters, such as Lighting Effects, Cutout, Stained Glass, Chrome, Ripple, Spatter, Sprayed Strokes, and Glass filters. (For example, with the Stained Glass filter, increase cell size. With the Cutout filter, increase Edge Simplicity, or decrease Edge Fidelity, or both.)
• If you plan to print to a grayscale printer, convert a copy of the image to grayscale before applying filters. However, applying a filter to a color image and then converting to grayscale may not have the same effect as applying the filter to a grayscale version of the image.