Up-sampling Image Size in Photoshop CS5
Anisotropic Filtering and Sharpening
A Technique for Enlarging Images in Photoshop
It is practically impossible to enlarge an image without some loss of resolution. There are some techniques for enlarging which do however retain some of the detail and clarity of the original image.
Tucked away in the Stylize section of the Filter menu, anistropic filtering is an advanced filter that tends to smooth away some of the blockiness or aliasing that is likely to occur when an image is digitally enlarged.
In this article we look at ways of reducing aliasing using the anisotropic filter and we then focus on how to give the image that sharpness and crispness that disappears after enlargement. This isn’t magic, but if you look at the images you should see some definite improvement.
Enlarged and Enhanced.