When you need to display or reproduce a photograph that includes people, products, locations or logos you're not authorized to depict, you can obscure recognizable details using a form of image distortion that turns details into patterns of color blocks. This technique is called "mosaic" because its results resemble an assembly of mosaic tiles. Adobe Photoshop includes a Mosaic filter whose output you can customize to suit your photograph, image size and document resolution.
Open the "Window" menu and choose "Layers" to bring up the Layers panel if it isn't already visible. Drag your "Background" layer onto the "Create a New Layer" icon at the bottom of the panel to duplicate it so your original image remains intact.
Activate the Rectangular Marquee tool in the Adobe Photoshop toolbox. Click and drag around the area you need to obscure, creating an active selection.
Open the "Filter" menu, click on its "Pixelate" submenu and choose "Mosaic." The Mosaic dialog box opens on your screen.
Click on the "Preview" check box in the Mosaic dialog box so you can evaluate your settings as you refine them. Enlarge the cell size until your selection area's details become unrecognizable. Click on the "OK" button to apply your effect when you're satisfied with it.
Save your file in Adobe Photoshop's native PSD format so you can return to it later for other refinements. Flatten the image and save it under another name as a TIFF document, then use this flattened version in your project.
Tips & Warnings
- The Mosaic filter's cell-size setting produces different results in a 72 pixel-per-inch file than in one at 300 pixels per inch because the same number of pixels covers a larger image area in a low- than in a high-resolution document.
- Unlike many Photoshop filters, Mosaic produces no results if you reapply it with the same settings to the same image area and through the same selection. That's because once it turns image details into colored squares, it can't perform further operations unless you change the cell size, the selection or both.
- Don't apply destructive filters to your only copy of an image. Always work on duplicate layers or in duplicate files.
- Don't apply Mosaic to a duplicate layer and send out the unflattened file for reproduction. The recipient can hide or remove your duplicate layer, thereby defeating the purpose of your obscuring mosaic.
- Photo Credit Hemera Technologies/AbleStock.com/Getty Images
- The Photoshop CS3/CS4 WOW! Book; Linnea Dayton and Cristen Gillespie
- The Photoshop CS/CS2 WOW! Book; Linnea Dayton and Cristen Gillespie
- Photoshop Restoration and Retouching, Third Edition; Katrin Eismann and Wayne Palmer