[bmmp]

In Photoshop there is an option to convert images from 8 Bits to 16 Bits and vice-versa. (Under Image Menu)

What is that?
What are the benefits for each?

[scadboy]

taken from photoshop's help page:

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:

*snip

Basically, the 16bit has better color distinction, but at up to twice the file size. As of version 7, you could only use a few of the tools available in photoshop to edit 16bit images, so 8bit images have the advantage of being more malleable. I understand Photoshop CS removes this limitation, and allows full editing of 16bit images, yes?

interesting...

ciao,

[bmmp]

neato.

thanks.

[gadster]

bmmp, if you can scan in 16 bit, you can bring it into photoshop and do all sorts of colour correction. Then, when you convert it down to 8 bit, the histogram (levels graph) comes out all smooth and purty. Photoshop has all 16 bits to use to build the 8 bit histogram. OTOH, if you do a lot of corrections to an 8 bit image, the histogram gets all sparse from the data loss. Less data, less image. So, to take advantage, you have to start at 16 bit.