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. In addition, only the following Photoshop tools and commands are available for 16-bit-per-channel images:

• The marquee, lasso, crop, measure, zoom, hand, pen, eyedropper, history brush, slice, color sampler, clone stamp tools, healing brush tool, and patch tool, as well as the pen and shape tools (for drawing work paths only).
• The Duplicate, Feather, Modify, Levels, Auto Levels, Auto Contrast, Auto Color, Curves, Histogram, Hue/Saturation, Brightness/ Contrast, Color Balance, Equalize, Invert, Channel Mixer, Gradient Map, Image Size, Canvas Size, Transform Selection, and Rotate Canvas commands, and a limited set of filters. (See Using filters.)

To take full advantage of Photoshop features, you can convert a 16-bit-per-channel image to an 8-bit-per-channel image.

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

1. To convert to a 16-bit-per-channel image, first flatten the image. (See Flattening all layers.)
2. Choose Image > Mode > 16 Bits/Channel or 8 Bits/Channel.