1. A method of obtaining a new picture attribute field of an image from an existing picture attribute field of the image and a pixel colorimetric parameter field of the image, the method comprising the steps of, receiving an image, by a processor, having one or more picture attribute values each associated with said image at an originally associated position in said image, said originally associated positions representing a first sampling frequency; for one or more new positions in the image representing a second sampling frequency different from said first sampling frequency, allocating said picture attribute value at an originally associated position to the new position in the image in dependence upon the value of a pixel colorimetric parameter at the originally associated position L original and the value of said pixel colorimetric parameter at the new position in said image L new and optionally in dependence upon the distance between the new position and the originally associated position, in which the allocation depends on a weighted sum D of a distance parameter r and a pixel colorimetric value difference L original −L new ; and outputting the image with each picture attribute value associated therewith at said new position; where 
 D=w 1 ·r 2 +w 2 ·|L original −L new | where w 1 and w 2 are weighting factors where w 1 may take the value zero and w 2 is always non-zero.