The PS Arbitrary Map effect is intended only to provide compatibility with projects created in earlier versions of After Effects that use the Arbitrary Map effect. For new work, use the Curves effect.

The PS Arbitrary Map effect applies a Photoshop arbitrary map file to a layer. An arbitrary map adjusts the brightness levels of an image, remapping a specified brightness range to darker or brighter tones. In the Curves window in Photoshop, you can create an arbitrary map file for the entire image or for individual channels.

This effect works with 8-bpc and 16-bpc color.

You can import and apply an arbitrary map file with Options in the Effect Controls panel. When loaded into After Effects, the specified arbitrary map is applied to the layer or to one or more channels of the layer, depending on how it was created. If you don’t select an arbitrary map, After Effects applies the default map (linear distribution of brightness) to the layer. Although you can’t import .acv or Photoshop spline files into the After Effects PS Arbitrary Map effect, you can convert these files in Photoshop to create files that are compatible with the After Effects Curves effect.

To convert .acv and Photoshop spline files, load the .acv file (Windows) or the Photoshop spline file (Mac OS) in the Curves dialog box, click the Pencil tool, and then save the file as an .amp file (Windows) or Photoshop lookup file (Mac OS).

Phase

Cycles through the arbitrary map. Increasing the phase shifts the arbitrary map to the right (as viewed in the Curves dialog box); decreasing the phase shifts the map to the left.

Apply Phase Map To Alpha

Applies the specified map and phase to the layer’s alpha channel. If the specified map doesn’t include an alpha channel, After Effects uses the default map (linear distribution of brightness) for the alpha channel.