Represents the "Alternate" entry of the icc profile stream dictionary object.

It is an optional entry defined as part of the PDF 1.0 specification.

It contains a ColorSpaceElement.

For definitive details see:.

The ISO PDF Specification, ISO 32000-1:2008 PDF 1.7; Table: 66, page 150.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 65, page 188.

The Alternate entry provides a fallback color space for use when ICC processing is not available. The alternate space must have the same number of components as N to allow color values to be passed through without reinterpretation.

A conforming reader that does not support ICC color management may use the alternate space to approximate the appearance of the content. Device color spaces are commonly used as alternates.