The present disclosure generally relates to a method and device for obtaining three color difference components from three components C1, C2 and C3 representing colors picture data in an input color space, a first of said color difference components being defined from the component C1, a second of said color difference components being defined from the first color difference component and the component C2, and a third of said color difference components being defined from the first color difference component and the component C3. The method is characterized in that it further comprises: —obtaining a first component by applying a process to the component C1; —obtaining said first color difference component by applying the inverse process to the first component.