Converting between bit depths

A 16-bit-per-channel image provides finer distinctions in color, but it can have twice the file size of an 8-bit-per-channel image. Photoshop CS provides more support for working with 16-bit-per-channel images:

• All tools in the toolbox, except the Art History Brush tool, can be used with 16-bit-per-channel images.
• All color and tonal adjustment commands, except Variations, are available, and a limited set of filters. (See Using filters.)
• You can work with layers, including adjustment layers, in 16-bit-per-channel images.

To take advantage of certain Photoshop features, such as Extract, Liquify, Pattern Maker, and some filters, you can convert a 16-bit-per-channel image to an 8-bit-per-channel image. It's best if you do a Save As and convert a copy of the image file so the original file retains the full 16-bit-per-channel image data.

To convert between 8 bits per channel and 16 bits per channel:

Choose Image > Mode > 16 Bits/Channel or 8 Bits/Channel.