Scan In 16- Or 8-Bit?

Q) I’ve been scanning slide film on the Nikon Coolscan V ED in 16-bit mode, but this yields a big 130 MB file, which further enlarges during Photoshop CS3 editing. The large file won’t open in Photoshop Bridge. If I scan in 8-bit, will my file quality suffer?

G. McLaughlin
Oceanside, California

A) You need at least 4 GB of RAM to move big files along. So you may need to improve your computer’s capability. You may have a setting in Photoshop Bridge that is preventing the thumbnail from loading. Go to Edit > Preferences > Thumbnails and enter a larger file size in the box “Do not process files larger than:”

If the image you are scanning will need considerable amounts of Photoshop editing, it’s a good idea to scan in 16-bit. Examples include files with lots of dark areas that will need to be lightened or original slides of poor quality. The 16-bit scan will give you more data to work with, and your corrections to the image will be less damaging. If the image being scanned is of good technical and physical quality, then an 8-bit scan will be more than adequate and you won’t be able to see the difference between it and a 16-bit scan.

An image like this 8-bit scan of a landing snow goose can be optimized in Photoshop without any problem. Because the image is well exposed and doesn’t have excessive contrast, the extra data a 16-bit scan would yield isn’t needed. The image was taken using a Canon EOS-1N film camera, 300mm f/2.8L lens (with 2X tele-extender) on Kodak E100S slide film and scanned with a Nikon Super Coolscan 5000.

George Lepp

One of North America’s best-known contemporary outdoor and nature photographers and a leader in the field of digital imaging and photographic education, Lepp is the author of many books and the field editor of Outdoor Photographer magazine. One of Canon’s original Explorers of Light, Lepp finds inspiration in advancing technology that fuels creative innovation and expression of his life-long fascination with the natural world.