User Manual

The HSL Curves
Three sets of Hue curves, and additional Lum vs. Sat and Sat vs. Sat curves, let you make
different types of curve-based alterations to the image. Whereas the Custom curves let you
make adjustments to the color channels of an image based on tonality (for example, boosting
the Red channel in the highlights while lowering it in the shadows), the Hue curves let you make
adjustments to the hue, saturation, or luma of elements in an image based on their hue.
Curves controls including six-vector selection and bezier handle button
For example, you could use the Hue vs. Sat curve to selectively lower the saturation of
everything that’s blue, while raising the saturation of everything that’s red.
You can use these curves to make adjustments similar to those made using HSL qualification,
but with one critical difference. Curve adjustments are mathematically smoother than the
matte-limited adjustments of HSL qualifiers, so it can sometimes be easier to make specific
alterations that blend smoothly with the rest of the image, without the potential for artifacts at
the edges of qualified keys that can sometimes defeat a seamless result.
On the other hand, it is often easier to define more distinct boundaries between separate
elements using HSL qualification. Only time and experience will help you determine which tools
are best for which situations.
Right–Original image, Left–the image as altered by the Hue vs. Sat curve shown above
Chapter – 118 Curves 2687