An ellipsoid chroma region of a chroma plane may be defined to specify a range of chromas for which a secondary chroma modification is to be applied, and to determine an output chroma for each chroma of the chroma plane based on the ellipsoid chroma region. Further, two or more different-shaped chroma regions of a chroma plane may be defined and manipulated, each chroma region specifying a range of chroma for which a secondary chroma modification is to be applied, and to determine an output chroma for each chroma of the chroma plane based on the two or more different-shaped chroma regions. Also, chroma-matching techniques may be used to define and manipulate the chroma region of a chroma plane that specifies a range of chroma for which a secondary chroma modification is to be applied, and an output chroma may be determined for each chroma of the chroma plane based on the chroma region.