Lab Color

An international standard for color measurements developed by the Commission Internationale de L'Eclairage (CIE). It's capable of reproducing all the colors of RGB and CMYK and uses three channels - one for luminosity and the other two for RGB type color ranges.

Some users prefer to work in this mode as it's device independent and colors that fall into the CMYK gamut aren't changed when you convert to CMYK.

Lasso

There are three Lassos to pick from the toolbox. The two standard versions, Freehand and Polygon and a Magnetic version.

The Freehand Lasso is used in most programs and is used by accurately drawing round the subject. You can select a feather to be applied to the section and turn anti-aliasing on or off.

The Polygon Lasso is good for drawing round boxes and straight edged items as it creates a straight edge between the source and destination point.

Magnetic Lasso is arguably the most useful Lasso. You draw roughly around the subject and the Lasso detects contrast changes and defines the edge. It then pulls the inaccurate drawing into line, often creating a very good selection.

Layers

One of the most useful features of Photoshop is Layers.