Pushing Ektachrome is part of the work flow, but needs to be done judiciously. Pushing increases the base speed of the film at the expense of contrast and film grain. Color fidelity also suffers from the push process. Ideally, Ektachrome should be exposed properly first, then decided upon if the push is necessary.
Under my conditions the standard work flow was to shoot at f/4.8 or f/5.6 with 35 to 50 minutes exposures. These apertures were chosen based on my lenses used and was their ideal f-stops. These included the Pentax 67 105, 165, 200, and 400 lenses. The 105 and 165 were ideal at f/4.8, the longer lenses, f/5.6
At these apertures, exposures needed to be long enough to just reach my natural sky fog levels, these were around 40-50 minutes near my horizon, to 50-75 minutes (or longer) near the zenith.
My standard push was 1.5 stops (Yes you can request fractional pushes) and this brought or the faint details, created a lighter transparency which is ideal for scanning, all without sacrificing color fidelity. This was only for E200, my standard film.
So there are many factors to consider. Bright regions such as Sagittarius and Scutum may not need pushing, given adequate exposure. If your resulting exposure looks dark on the film, expose longer. Pushing should not really be used as a substitute for shorter exposures. Exposing property should be the first consideration.
Pushing Ektachrome can help with the overall image quality of the end result, given a good work flow for exposure / lens aperture selection. Be careful of high contrast situations such as the area of the Orion Nebula, and the Lagoon Nebula. Pushing can burn these areas out. Useful as a tool, pushing can reveal subtle passages of nebulae not as easily rendered by standard development.
Subtle nebulae in the gamma Cygni region revealed by Kodak E200, pushed 1.5 stops using the Pentax 67 300mm @5.6 and 75 minutes exposure.
Edited by Nightfly, 19 October 2019 - 05:30 AM.