An image decoding unit arranged to obtain a high dynamic range image (IM_HDR_out) from a high dynamic range image encoding (Im_1*) comprising: - an LDR recovery unit arranged to determine a low dynamic range of luminances (R_Norml_LDR), or corresponding range of luma code values (R_LDR), within a total range of luminances (Range_HDR) covered by the high dynamic range image, the low dynamic range of luminances (R_Norml_LDR) or corresponding range of luma code values (R_LDR) being so large that image information encoded within it is usable for LDR rendering, and arranged to obtain a low dynamic range image (Im_LDR_o) from the high dynamic range image encoding (Im_1*); - an HDR recovery unit arranged to determine at least one complementary range (R_above) within the total range of luminances (Range_HDR), comprising luminances not covered by the low dynamic range of luminances (R_Norml_LDR), and arranged to determine at least one high dynamic range subimage (ImP_HDR_o) from the high dynamic range image encoding (Im_1*) corresponding to that at least one complementary range (R_above); - an image composition unit arranged to compose the high dynamic range image (IM_HDR_out) from the low dynamic range image (Im_LDR_o) and the at least one high dynamic range subimage (ImP_HDR_o), whereby the low dynamic range image (Im_LDR_o) and the at least one high dynamic range subimage (ImP_HDR_o) cover non-overlapping luminance subranges of the high dynamic range image (IM_HDR_out), characterized in that the composition of the high dynamic range image (IM_HDR_out) is performed by applying an inverse of a first mapping (CMAP_L) to the lumas of the low dynamic range image (Im_LDR_o) and by applying an inverse of a second mapping (CMAP_H) to the lumas of the the at least one high dynamic range subimage (ImP_HDR_o), which first and second mapping are received in metadata co-communicated with the high dynamic range image encoding (Im_1*). - an LDR recovery unit arranged to determine a low dynamic range of luminances (R_Norml_LDR), or corresponding range of luma code values (R_LDR), within a total range of luminances (Range_HDR) covered by the high dynamic range image, the low dynamic range of luminances (R_Norml_LDR) or corresponding range of luma code values (R_LDR) being so large that image information encoded within it is usable for LDR rendering, and arranged to obtain a low dynamic range image (Im_LDR_o) from the high dynamic range image encoding (Im_1*); - an HDR recovery unit arranged to determine at least one complementary range (R_above) within the total range of luminances (Range_HDR), comprising luminances not covered by the low dynamic range of luminances (R_Norml_LDR), and arranged to determine at least one high dynamic range subimage (ImP_HDR_o) from the high dynamic range image encoding (Im_1*) corresponding to that at least one complementary range (R_above); - an image composition unit arranged to compose the high dynamic range image (IM_HDR_out) from the low dynamic range image (Im_LDR_o) and the at least one high dynamic range subimage (ImP_HDR_o), whereby the low dynamic range image (Im_LDR_o) and the at least one high dynamic range subimage (ImP_HDR_o) cover non-overlapping luminance subranges of the high dynamic range image (IM_HDR_out), characterized in that the composition of the high dynamic range image (IM_HDR_out) is performed by applying an inverse of a first mapping (CMAP_L) to the lumas of the low dynamic range image (Im_LDR_o) and by applying an inverse of a second mapping (CMAP_H) to the lumas of the the at least one high dynamic range subimage (ImP_HDR_o), which first and second mapping are received in metadata co-communicated with the high dynamic range image encoding (Im_1*).