For serving the new different needs of high dynamic range image handling and conversion of images to a different dynamic range in decoding strategies the inventor invented image encoder (201) for encoding at least one high dynamic range image (HDR _ORIG) for at least one time instant, and at least one image (Im_LDR_out) of a second dynamic range which is different from the one of the high dynamic range image by at least a factor two for the same time instant, which is arranged to encode a matrix of pixel colors for at least one of those two images, comprising a specification unit (212) which comprises a color saturation modification apparatus (202) as claimed in claim 1, and a saturation specification unit (204) arranged to specify a saturation modification specification function specifying a color-dependent saturation transformation, as a set of gains (g) for each possible value of a maximal one of at least two color difference values (R'-Y', B'-Y') of a pixel color (Y',Cb,Cr), which color difference values are defined as the value of a non-linear RGB additive color component of the pixel color minus the luma of the pixel color,, and the image encoder further comprising a formatter (210) arranged to output in an image signal (S_im) an encoding of an image (Im_in_DCT) comprising the matrix of pixel colors, and as metadata the set of gains (g).