Last month, I discussed several tools and techniques for removing backgrounds from your images. Today, I'd like to introduce you to three free filters that can make removing certain backgrounds a breeze in any application. These filters work on images where the background is primarily white or black. Unfortunately, of the three, only one is available for Macintosh users. The filters should function in any graphics program that supports Photoshop-compatible filters. Consult your software manual for details on installing and accessing plug-in filters.
While stripping an image from a solid colored background is generally not all that difficult or time consuming, these free filters can make it as simple as choosing a menu item. All three of the filters require that your image be in RGB color mode and they will only function on a layer. If your image is on the background, you must first promote it to a layer before running the filter.
These filters are especially useful for black and white line art when you need to isolate just the white or black pixels on a layer. They can also be used to create various effects. On the next page, I'll show you several examples of what you can do with these filters. Here's a summary of each filter, with a link to the page where you can download them:
Eliminate White strips the active layer of white pixels. Light-colored pixels in the layer are made partially transparent based on the level of whiteness. (Windows and Macintosh versions available)
Works just like the Eliminate White filter, but for images with a black background. Pure black pixels are made 100% transparent and dark-colored areas in the layer become partially transparent based on the level of blackness. (Windows Only)
Whitewash is almost identical to the Eliminate White filter, but it's written in assembly language so it uses less memory and runs faster. It sets transparency according to the whiteness of the pixels in your image. Another difference between Whitewash and Eliminate White, is that the Whitewash filter can be run repeatedly on a layer to increase the whitewashing effect. (Windows Only)
Here's a bit more information and examples to help you understand how these filters work...
the right is an example that shows you the differences between
the three filters. Where you see the checkerboard pattern, the
pixels have been converted to transparent. As you can see, there
is no visible difference between the results of the Whitewash
and the Eliminate White filters.
To say that these filters only affect the white and black areas in the image can be somewhat misleading. As you can see from this example where the Whitewash filter was used, colored areas are also affected based upon the RGB values of each pixel. Notice that the white pixels have been converted to 100% transparency, while other light colored areas are partially transparent. Black pixels remain 100% opaque.
This makes it somewhat unpredictable when applying the filters to colored images, but with some experimentation, you can get a feel for what to expect. Here's a couple more comparisons using colored gradients to demonstrate the differences:
For several examples of real-world applications for these filters, continue on the to the next page to see the results of my experimentation. There's quite a few images on the next page, please be patient as the images load.
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Some images from Nova Development's Art Explosion 600,000.