Cadmium alternatives, often called permanent colours, are made to be equal to the cadmium shades in tone and brightness. These shades, however, are much easier to mix and tone down, as is demonstrated in this video. Permanent colours are semi-opaque, which allows them to show a little more of underlying colours or canvas, unlike the extremely opaque cadmiums.
Whether you want to work with cadmiums or permanent colours depends on what you want to achieve in your painting. The video below shows a selection of cadmium colours compared to their permanent counterpart. All shades are shown by themselves and mixed with other colours to show their effects. Keep these examples in mind to help you select the right colours for your next painting.