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Note Submitter: timeshifting at gmail dot com ---- To sharpen an image, rather than using the code below that produces a sharpening filter with php, use the built-in GD function "imageconvolution" which is designed for this purpose. Matrices can be used for sharpening, blurring, edge detection, etc, ala Photoshop. A sharpening example: <?php $sharpenMatrix = array(-1,-1,-1,-1,16,-1,-1,-1,-1); $divisor = 8; $offset = 0; imageconvolution($myImage, $sharpenMatrix, $divisor, $offset); ?> Below is some information on building different kinds of matrices. (If you have photoshop (or PSP, GIMP) you can test out your matrices before applying them in PHP) http://loriweb.pair.com/8udf-basics.html (covers blurs) http://loriweb.pair.com/8udf-sharpen.html http://loriweb.pair.com/8udf-edges.html http://loriweb.pair.com/8udf-emboss.html