The Ha image of Rosette was "colorized" using scan of a film photograph which was send to me by Artur Wrembel. The film image was a source of RGB signal, while Ha image was used as Luminance.

The strange coloring in part of the nebula is a result of different sensitivity of film versus CCD in Ha - the Ha image boosted brightness of the sky in areas, where the film did not record nebulosity.

Both images were co-registered using Astroart functionality.