"Black" and "white" points here are pixel counts from the darkest and brightest ends respectively. To turn the darkest 90% of the pixels black, and the brightest 5% white, use the following:<?php$im = new Imagick ("some image.png");list ($width, $height) = array_values ($im->getImageGeometry ());$px = $width * $height;$im->modulateImage (100, 0, 100);$im->linearStretchImage ($px * 0.9, $px * 0.05);$im->writeImage ("temp.jpg");?>