in Images and Color
CAN'T STAND BANDING?|
Camera Raw vs. JPG... Why Is 16-Bit Better?
The reason why you should opt for 16-bit camera RAW vs. 8-bit JPG when taking digital camera photographs is easy to demonstrate but harder to explain. That's why we've started with the demonstration, which is followed by a more in-depth explanation below.
Understanding The Issues
Most digital cameras now give you the option of taking photographs with 16-bit grayscale per color channel. Yet when an image is rendered to JPG for the Web or CMYK for print, each channel is limited to 8-bit. The question then, is why bother storing twice the data when you aren't going to use it anyway?
The answer lies in preserving quality even after image adjustments or retouching. The human eye is quite good at perceiving abrupt changes in tone (think of banding in a blend, for example). It turns out that 256 levels (8-bit) of gray per color is barely enough tone values to be perceived as a smooth blend. Every time you make an adjustment (think curves, levels, brightness or contrast, etc.), you are in effect moving some of the original tone values one way or another, in effect creating gaps in the tone map.
If you only start out with 256 levels of gray, even a few color adjustments will bring the tone distribution below the minimum threshold necessary to be perceived as smooth. Yet if you start with 16-bit color, you have so many levels to work with, you can apply many rounds of image edits without having any perceptible impact on the eventual 8-bit tone distribution.
Two Workflow Options
For simple, one-step editing:
For complex editing:
Note that these issues only apply to the creative phase of your project. We typically work only in CMYK, which is by definition 8-bit. This workflow is relevant before you submit your job for printing, not after.
The video below explains this issue with its own examples. If you still have questions, take two minutes and watch it!