Photoshop Filter Guide
Click on a Filter Category to view a sample of the Filters

Artistic

Custom

Lets you design your own filter effect. With the Custom filter, you can change the brightness values of each pixel in the image according to a predefined mathematical operation known as convolution. Each pixel is reassigned a value based on the values of surrounding pixels. This operation is similar to the Add and Subtract calculations for channels.
You can save the custom filters you create and use them with other Photoshop images.

To create a Custom filter:
Choose Filter > Other > Custom.
Select the center text box, which represents the pixel being evaluated. Enter the value by which you want to multiply that pixel's brightness value, from -999 to +999.
Select a text box representing an adjacent pixel. Enter the value by which you want the pixel in this position multiplied.
For example, to multiply the brightness value of the pixel to the immediate right of the current pixel by 2, enter 2 in the text box to the immediate right of the center text box.

Repeat steps 2 and 3 for all pixels to include in the operation. You don't have to enter values in all the text boxes.
For Scale, enter the value by which to divide the sum of the brightness values of the pixels included in the calculation.
For Offset, enter the value to be added to the result of the scale calculation.
Click OK. The custom filter is applied to each pixel in the image, one at a time.
Use the Save and Load buttons to save and reuse custom filters.

Retains edge details in the specified radius where sharp color transitions occur and suppresses the rest of the image. (A radius of 0.1 pixel keeps only edge pixels.) The filter removes low-frequency detail in an image and has an effect opposite to that of the Gaussian Blur filter.

It is helpful to apply the High Pass filter to a continuous-tone image before using the Threshold command or converting the image to Bitmap mode. The filter is useful for extracting line art and large black-and-white areas from scanned images.

Useful for modifying masks. The Maximum filter has the effect of applying a choke--spreading out white areas and choking in black areas. As does the Median filter, the Maximum filter looks at individual pixels in a selection. Within a specified radius, the Maximum filter replaces the current pixel's brightness value with the greatest brightness value of the surrounding pixels.

Useful for modifying masks. The Minimum filter has the effect of applying a spread--spreading out black areas and shrinking white areas. As does the Median filter, the Minimum looks at individual pixels in a selection. Within a specified radius, the Minimum filter replaces the current pixel's brightness value with the least brightness value of the surrounding pixels.

Offset

Moves a selection a specified horizontal or vertical amount, leaving an empty space at the selection's original location. You can fill the empty area with the current background color, with another part of the image, or with your choice of fill if the selection is near the edge of an image.

Create Seamless Tiles or Textures