I work for an institution with a large photographic archive of art, containing among other things colour negatives and ektachrome films. My team is digitizing the films and in the meantime we want to restore the colours as good as possible (the films have degraded in different degrees throughout the years).
Often a colour chart is photographed together with the piece of art, f.e. the Kodak Q13 or similar patches (example). Yet, I do not succeed in using these charts for a good colour restoration. I know the charts were intended for a good reproduction on print and not for digital restoration (see another question on this topic), but still, I really suspect that there is a way to use this information.
Software solutions for reading colour charts point me in the direction of camera or scanner calibration (f.e. Adobe DNG profile editor or Silverfast), but I do not find a way to use this to restore a colour photograph.
FYI: on this moment we do colour restoration in Photoshop, based on the 90% method, using the whites and blacks in the image and getting them right with the levels or curves tool. Sometimes this is enough, but sometimes it is not.
Any experience with this matter?