Shot and Push-Processed Ilford HP5 at 12800 - results

i strongly suspect -- just guessing here -- that your actual film speed was not that high, but you sure got something and that's all that matters. There are limits, mostly as the developer get's used up, but HP5 is also very forgiving.

Do it again, see if it is reproducable. You never know.

 

They look pretty good. Another poster seems to have questioned whether your speed was in fact 12,800. I can only surmise that this may be due to your use of the word "over" . For clarity do you mean that after getting the right exposure for 6400 you went to a higher shutter speed ie. if the shutter speed for 6400 was 1/30th then you moved to 1/60th( underexpose) as opposed to 1/15th(overexpose) compared to what the meter said?

Thanks

pentaxuser

 

Give it a try with a Rodinal equivalent developer with semi stand development. What you got looks pretty impressive so far.

 

Thanks and I'd agree. Maybe this has clarified it for the poster in question as well. The meter may of course be wrong but otherwise in the absence of any evidence I cannot work out how the poster can suspect strongly that your speed was lower. He may now tell us what he believes the evidence to be for this belief

pentaxuser

 

It is important to understand that push processing doesn't really increase the light sensitivity of the film (much).
What it does do is increase the contrast of that part of the scene where there was enough light to cause at least some image to be formed.
A push development attempting to achieve an Exposure Index of 12,800 is a five stop push.
Your results are fairly useful because there are enough highlights in your subjects which can survive five stops of under-exposure, once the resulting murky low contrast is boosted back to near normal with the increased development.
The shadows and low mid-tones in the scene can't survive that much under-exposure - that is normal.

 

Real world, you were probably closer to an EI of 1600 than 12800 - those subjects might well fall closer to an EV of 4-5 in actuality.

 

Lachlan, I am unsure what you mean in terms of how this affects what the OP did with his meter when he set it to 6,400 and then halved the meter's exposure so it was as if he had set his meter to 12,800. Your quote seems to explain why the other poster said the real speed was lower. Can you expand on the above

Thanks

pentaxuser

 

It doesn't look like pushing HP5+ to 12,800 is that great an idea. I can't remember ever encountering a low light setting that would require it, especially for those indoor music venue images. That's five stops from ISO 400. For indoor, 1/30th at f/2 is a common exposure. Your light reading was 1 sec at f/2 or something? Or was this just an experiment?

 

Take a look here:
http://www.fredparker.com/ultexp1.htm#Light Intensity Chart

Working from known EV's is often a pretty accurate way to estimate light - and then compare what the table states with the lighting in the images. As an aside, the whole reason why Kubrick used those T0.7 lenses for Barry Lyndon was because he was trying to get an EV of 4 (candle light) to work on Kodak 5254 (100T, could be pushed a stop at maximum) - and none of the images above are under anything darker than what the EV table defines as representing an EV of 4 - at least for reproduction of the scene as your eye would 'perceive' it - & in those specific lighting situations, the shadows are normally quite dark.

 

Thanks Lachlan. It would appear that from the EV tables in Lachan's link, the pictures taken by the OP were around say EV 4-5. However to work out what the means in terms of correct aperture and speed we need to know what his shutter speed and aperture was. So at EV4 the tables gives a range of speeds for various apertures which result in correct exposure for an ISO of 100. Once we know the shutter speed and aperture we can then work forward in stops, 100,200 400 etc and arrive at what film speed his shutter speed and aperture corresponds to in order to see how close it was to ISO1600.

I may be wrong but throughout the thread I think we have only spoken of theoretical examples of speeds and nowhere is there actual speeds and apertures

So, OP can you give us your shutter speeds and apertures for the shots you took.

Thanks

pentaxuser