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Push process new Kodak Ektachrome 100 1 Stop

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#1 Tony Pilato

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Posted 11 October 2019 - 04:28 PM

I remember (in the past) some astrophotographers push processing  Kodak Ektachrome 200 1 Stop. Other than the speed increase did it lower contrast a bit? 

 

Should I push process the new Kodak Ektachrome 100 1 Stop as well? Longer exposure time at ISI 100 vs ISO 200 is not an issue, 

 

Comments please? 

 

I am usually a hypered negative astrophotographer. Limited experience in Positive films.

 

Thanks,

Tony 

See www.darkstarImages.com for some examples of hypered negative long exposure images.


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#2 fcathell

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Posted 11 October 2019 - 04:38 PM

Tony - the contrast will come up but the graininess will increase.  It would be similar to enlarged pixel size in a CCD cam.  God, I remember doing this to Fuji 400 after hypering it.  I still have most of the old astrophoto slides from the early 80s. I didn't know anyone was using real film any more!  Good luck!

 

Frank

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#3 fcathell

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Posted 11 October 2019 - 04:48 PM

Tony - went to you website.  Fabulous images for film astrophotography. Does this ever bring back memories! How long do you typically guide/expose?  I assume you use the C11 with a F/6.3 focal reducer and off-axis guider for most of these.

 

Frank

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#4 SMigol

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Posted 11 October 2019 - 04:50 PM

I've not pushed fresh slide film.  I'd defer to Nightfly's expertise with using fresh ektachrome.

 

I'm also curious about the topic as I have a roll of 30 exposures waiting to be developed.  

 

Most of the exposures on my roll are 40-60 minutes at F5.  I don't think they'll need pushing, but it might do well to help with the background sky.



#5 msl615

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Posted 11 October 2019 - 05:39 PM

Back a long time ago, I used to push Ektachrome all the time in my own darkroom. I did not know that they still sold the Ektachrome processing chemicals? You can push in fractions too, if you don't want to go with a full stop worth of extra development time. It will increase the contrast and graininess as fcathell noted.  On the other hand, you are only pushing EK100 to 200. Not that much outside its limits. If you were trying to take 200 up to 400,600 or 800, then it gets pretty weird.

Another factor: You are going to move into the world of long exposure reciprocity failure for the Ektachrome. My memory is that a calculated exposure of anything longer than about 1 min will actually require 1.5 min and colors start to change, etc.  But, this is probably covered in a range of excellent film exposure astro books. 

 

My suggestion if you have your own kits: Push some test rolls before the important images. 

 

Mike



#6 Tony Pilato

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Posted 14 October 2019 - 04:46 PM

Thanks everyone.

 

My images on my site are both F/6.3 and F/10. Exposures times and F/Stops are in the description at the bottom. I may be the only one still using hypered film at slow F/Stops but for a variety of reasons. I will continue using film at F/10, maybe some F/6.3 until the end. I realize that  some people will say that I could get  much better results with CCD etc, but the image "quality" (which I admire), but it has/will be my photon catcher until ?

 

Thanks,

 

Tony



#7 Nightfly

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Posted 19 October 2019 - 05:29 AM

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. 

 

Gamma Cygni Region
 
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.

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