Pushing Superia 800 to 12800
Thought I'd share this here too, negs were scanned on a frontier, which is very similar to how prints turn out (think fixed contrast grade, cant adjust, only density adjustments (exposure) and colour balance/filtration of a less fine degree then printing offers).
Developing method was C-41 + 600mg/L of Potassium Thiocyanate (thought this may give me extra speed) for a time of 6 minutes, followed up by a sodium carbonate bath to continue shadow development (although skip this, all it does is increase base fog, I forgot about that in C-41). You can also safely leave out the KSCN, I was experimenting.
This was also a preflashing experiment. The ideal preflash looks like 2 stops below camera middle grey reading at the rated EI of 12800. So if you set your meter to 12800, meter through whatever you're shooting your preflash with, and subtract 2 stops, you're there.
I would like to apply this to Portra 400 in the future, knowing the kind of push results I get at 1600, it may worth be trying at 6400 with preflash
These shots are all from the same roll. The metering for preflash was done through the camera meter (AE-1) through a tissue held tight over the lens, as was the exposure through the same tissue. The preflash was done prior to the scene exposure.
3200 no preflash
12800 no preflash
12800 + preflash Z1 (middle grey reading @ 12800 - 4 stops)
12800 + preflash Z2 (middle grey reading @ 12800 - 3 stops)
12800 + preflash Z3 (middle grey reading @ 12800 - 2 stops)
It doesn't matter whether printing or scanning, it should be clear the preflash method offers superior results to pushing alone, as it simply isn't about compressing shadow range to make it more printable, it helps put shadow detail onto the neg that simply doesn't exist at all, and it appears the contrast increase of the push helps alleviate scale compression from putting maximum and minimum exposure ever closer together with a preflash, so it appears a good combination.
Last edited by Athiril; 07-12-2013 at 07:46 PM. Click to view previous post history.
Great work. Keep it up.
I guess that pre-flash is getting you the requisite 3-4 atoms in areas where it's just on the threshold.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.
I wonder if this technique will work with ECN-2 film? I might try it with Fuji Eterna Vivid 500T, maybe try a push to 8,000 ISO.
This is the first I've heard of preflashing. I'm always looking for a bit more speed at those night football games. I usually just shoot HP5 at 3200 because Portra just didn't look that good above 1600 to me. I'll be trying this soon. So to make sure i have this correct, If I want to preflash 2 stops I meter through my diffusion material (tissue paper plastic, etc) at the ISO setting I'm going to shoot at, say 6400, then I just cut back the exposure 2 stops? So if my shutter speed was 1/500 though the tissue paper at 6400 I'd up it to 1/2000th, expose the film to the tissue paper then rewind and shoot the film normally at ISO 6400 and develop for ISO 1600 by pushing it 2 stops? Is there any advantage to doing this same method at rated speed. Would an ISO 400 film 2 stop pre-flashed at ISO 1600 developed at normal times be any better than just pushing 2 stops?
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I decided to test this, because all I could find was all talk and 'do your own testing' with no examples given. But it is clear some level of preflash is absolutely useless, and then a small change can all of a sudden have a massive impact. So really, you do need to do your own test, but at least it's a ball park figure of what to aim for, and of course, what to look for when it is working.
Essentially.. what you're going to need is a sacrificial test roll. Just 1 will do.
Figure your desired EI speed that you need to shoot at. 6400 is probably a good choice for Portra 400. Meter through your diffusion material, and shoot scenes, no preflash.. -5 stops, -4.5 etc etc. Though it will probably also be -3 to -2 from 6400.
You also need the developer time too to make the most of it.. 6 minutes in C-41 at normal process temp (~38 celsius) is still probably about right.
That's your starting point.
This will also work for your B&W film too btw, I've seen it primarily referenced for B&W in fact, so I decided to try it on colour.
In regards to pre-flashing with no push.. I do not know. But I suspect the preflash should be less -2 stops from middle grey reading, as there is still plenty of straight line scale left.. you probably want to pre-flash it at the bottom of the linear scale. Which is -4 stops from Box speed for Portra 400 (and most others too)
But the zone 3/-2 stops @ 12800 on Superia 800.. it's -2 stops below the published straight line curve according to Fuji.
So, you will need 1 test roll. Pre-flash different amounts and shoot a test scene at the desired underexposure/EI+push/etc, and take notes. The one to use will be when you see a sudden jump in detail like the above example.
If you shoot Portra 400 normally.. you can just save 6 or so exposures at the end of a roll for that purpose etc on your next roll. I imagine it wont be as good as combined with a push.
For example. Let us say your preflash has a value of x.
If one part of the image also has an exposure of x, and another 2x, instead of being 1 stop of separation between these two points if normally recorded.. with a preflash, it's essentially 2x and 3x, or the equivalent of 0.58 stops of separation on the neg.
So the push helps stretch this contrast back out, which can be very important. Although compressed values can also be desirable.
If you DIY C-41, I'd recommend just using 6 minutes @ 38c or so.. no additives needed.
It should work with any film, though with reversal/slide, I imagine you will severely limit dMax, unless you make a custom first dev for it.
Originally Posted by newcan1
great results !
have you tried pre flashing, and "hypering" with hydrogen peroxide & al.
and seen which gives you a better rendering ?
keep up the cool experiments !
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