Something that's missed is that often in the past (pre digital) professional photographers would often take two shots of ket images (almost always LF). same exposires and process just one, only processing the second if the result needed pushing/pulling. This was very common with E6. The other trick was to shoot two quick test shots and have a clip test done from the first roll. Many also forget that back in the 70's (and earlier) professional colour films came with suggested colour filtration adjustments stamped on each box. Here in the UK many switched to Fuji films as they were far more consistent, later Kodak caught up. Ian