A machine implemented method of saturation-adjusting one or more images, the method comprising: receiving an image encoded in an enhanced dynamic range format associated with a second colour space, wherein the second colour space is one of: a Y'C B C R colour space; a YC B C R colour space; an IPT colour space; and an ICtCp colour space, the image comprising a plurality of pixels, each of the pixels having an intensity component and two chroma components; receiving colour grading metadata associated with the image, the colour grading metadata comprising a plurality of saturation control values corresponding to respective different hues, wherein the plurality of saturation control values is a sequence of six saturation control values, corresponding to the hues red, yellow, green, cyan, blue and magenta, the plurality of saturation control values i) representing a desired saturation adjustment and ii) defining a first plurality of hue regions of a first colour space, the first colour space being different from the second colour space, wherein the first colour space is one of: a hue, saturation, value (HSV) colour space; a hue, saturation, lightness (HSL) colour space; or a hue, saturation intensity (HSI) colour space; for each pixel of the plurality of pixels, determining the pixel's hue and saturation from its two chroma components, determining a pixel saturation adjustment in accordance with the desired saturation adjustment, wherein the plurality of saturation control values have different contributions to the pixel saturation adjustment depending on the location of the respective pixel's hue relative to a second plurality of hue regions in the second colour space, the second plurality of hue regions corresponding one-to-one to the first plurality of hue regions, and applying the pixel saturation adjustment to the pixel's saturation; and outputting a colour-graded image in the enhanced dynamic range format, the colour-graded image comprising the saturation-adjusted plurality of pixels. for each pixel of the plurality of pixels, determining the pixel's hue and saturation from its two chroma components, determining a pixel saturation adjustment in accordance with the desired saturation adjustment, wherein the plurality of saturation control values have different contributions to the pixel saturation adjustment depending on the location of the respective pixel's hue relative to a second plurality of hue regions in the second colour space, the second plurality of hue regions corresponding one-to-one to the first plurality of hue regions, and applying the pixel saturation adjustment to the pixel's saturation; and determining the pixel's hue and saturation from its two chroma components, determining a pixel saturation adjustment in accordance with the desired saturation adjustment, wherein the plurality of saturation control values have different contributions to the pixel saturation adjustment depending on the location of the respective pixel's hue relative to a second plurality of hue regions in the second colour space, the second plurality of hue regions corresponding one-to-one to the first plurality of hue regions, and applying the pixel saturation adjustment to the pixel's saturation; and outputting a colour-graded image in the enhanced dynamic range format, the colour-graded image comprising the saturation-adjusted plurality of pixels. <EOS>