This is a post in Special Effects Tutorials

Grid Masking in Photoshop

This grid masking seems like an interesting technique to take a closer look at. First you need to create the grid mask in Adobe Illustrator. Then paste grid as a shape layer in Photoshop and the last step is to subtract shape layer.
Read the tutorial detail at Veerle’s Blog to create your own Grid Masking design using Photoshop!