Filters - Defining undistorted areas, Using texture and glass surface controls, Tips for creating special effects, Improving performance

Filters - Defining undistorted areas

The Displace, Shear, and Wave filters in the Distort submenu and the Offset filter in the other submenu let you treat areas undefined by the filter in the following ways:

• Wrap Around fills the undefined space with content from the opposite edge of the image.
• Repeat Edge Pixels extends the colors of pixels along the image's edge in the direction specified. Banding may result if the edge pixels are different colors.
• Set to Background (Offset filter only) fills the selected area with the current background color.

Filters - Using texture and glass surface controls

The Conté Crayon, Glass, Rough Pastels, Texturizer, and Underpainting filters have texturizing options. These options make images appear as if they were painted onto textures such as canvas and brick or viewed through glass blocks.

To use texture and glass surface controls:

1. From the Filter menu, choose Artistic > Rough Pastels, Artistic > Underpainting, Distort > Glass, Sketch > Conté Crayon, or Texture > Texturizer.

2. For Texture, choose a texture type or choose Load Texture to specify a Photoshop file.

3. Drag the Scaling slider to enlarge or reduce the effect on the image surface.

4. Drag the Relief slider (if available) to adjust the depth of the texture's surface.

5. Select Invert to reverse the surface's light and dark colors.

6. For Light Direction, indicate the direction of the light source on the image.

Filters - Tips for creating special effects

Try the following techniques to create special effects with filters.

Create edge effects

You can use various techniques to treat the edges of an effect applied to only part of an image. To leave a distinct edge, simply apply the filter. For a soft edge, feather the edge, and then apply the filter. For a transparent effect, apply the filter, and then use the Fade command to adjust the selection's blending mode and opacity.

Apply filters to layers

You can apply filters to individual layers or to several layers in succession to build up an effect. For a filter to affect a layer, the layer must be visible and must contain pixels--for example, a neutral fill color.

Apply filters to individual channels

You can apply a filter to an individual channel, apply a different effect to each color channel, or apply the same filter but with different settings.

Create backgrounds

By applying effects to solid-color or grayscale shapes, you can generate a variety of backgrounds and textures. You might then blur these textures. Although some filters have little or no visible effect when applied to solid colors (for example, Glass), others produce interesting effects. You might try Add Noise, Chalk & Charcoal, Clouds, Conté Crayon, Craquelure, Difference Clouds, Glass, Grain, Graphic Pen, Halftone Pattern, Mezzotint, Mosaic Tiles, Note Paper, Patchwork, Pointillize, Reticulation, Rough Pastels, Sponge, Stained Glass, Texture Fill, Texturizer, and Underpainting.

Combine multiple effects with masks or with duplicate images

Using masks to create selection areas gives you more control over transitions from one effect to another. For example, you can filter the selection created with a mask.

You can also use the history brush tool to paint a filter effect onto part of the image. First, apply the filter to an entire image. Next, step back in the History palette to the image state before the filter was applied, and set the history brush source to the filtered state. Then, paint the image.

Improve image quality and consistency

You can disguise faults, alter or enhance, or make a series of images look related by applying the same effect to each. Use the Actions palette to record the process of modifying one image, and then use this action on the other images

Filters - Improving performance

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.
• 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.