On the digital front end (DFE) of my press, I see different options for rendering intents for separating color. What are they, and what's the difference?

Rendering intents describe how out-of-gamut colors (like those in the RGB color space) are mapped to in-gamut colors (like those in the smaller CMYK color space). You have three options: saturation, perceptual, and colorimetric. Saturation moves out of gamut pixel colors to the closest in-gamut color, but also moves in-gamut colors outward. Saturation rendering intent is good for bar charts, pie graphs, and such, but not for most other image types. Perceptual moves out of gamut pixel colors in proportion to the in-gamut color and also moves in-gamut colors inward proportionally. Perceptual maintains the tonality of the image at the expense of color saturation. Colorimetric, like saturation, moves out of gamut pixel colors to the closest in-gamut color but has no effect on in-gamut colors. Generally speaking, the colorimetric rendering intent is best for most images and, in most software applications, is the default setting.