1. A method of image demosaicing comprising: receiving a digital mosaiced image; calculating a demosaiced image from the received image using a trained machine learning system, the demosaiced image being in a linear light-space of a color image processing pipeline, the trained machine learning system having been trained using pairs of mosaiced and demosaiced images, at least one of the pairs comprising at least one of: the mosaiced images having been formed by subsampling trained demosaiced images according to a color filter array pattern; or the demosaiced images having been calculated from mosaiced images of a natural scene using a downscaling process; and wherein a linear light-space is a stage of a color image processing pipeline at which a digital image has been linear color-scaled and black-level adjusted but at which a color transform and Gamma correction have not been applied to the digital image.