Push Processing Questions


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CoExist

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Got a rather easy qns out for the experts but confusing for a newbie :) if i have only 1 flim @ ISO 100, take lots of shot wif this and at night,some night shots, i push the sensitive to ISO400, snap snap some shots then back to ISO 100. Could i actually develop the flim to the majourity of the shots at ISO 100 then go to aldephi to push process the selected night shots at ISO 400??? Is this possible? coz of space constrain(cant bring 2 cams) and the fact the camera kinda scuk, i cant take out the flim half way to insert the ISO400 one.
 

Ah Pao

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Technically, "pushing" is a chemical process and is done through the whole roll. To "push" selected frames is not possible.

By shooting at EI (Exposure Index) 400 with ISO100 film, you have pushed your film by 2 stops. So either you push it by 2 stops and those that you shoot at EI400 comes out (hopefully) correctly exposed, with those shots at EI100 overexposed,

OR

If you don't push you film (i.e. develop as ISO100), then those shots taken at EI400 will come out underexposed.

The moral of the story is, don't switch ISO in between frames in the same roll of film.
 

Ah Pao

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#5
CoExist said:
coz of space constrain(cant bring 2 cams) and the fact the camera kinda scuk, i cant take out the flim half way to insert the ISO400 one.
Go buy a film picker...if your camera supports mid-roll rewinding.
 

coke21

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The questin is why did you push your film to 400 and then back to 100 after that? You could have just left it at 400 and continued taking your shots and then got the entire roll push processed.

guess not you have to decide which shots are the ones that you want to come out correctly.
 

Red Dawn

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#7
CoExist said:
Got a rather easy qns out for the experts but confusing for a newbie :) if i have only 1 flim @ ISO 100, take lots of shot wif this and at night,some night shots, i push the sensitive to ISO400, snap snap some shots then back to ISO 100. Could i actually develop the flim to the majourity of the shots at ISO 100 then go to aldephi to push process the selected night shots at ISO 400??? Is this possible? coz of space constrain(cant bring 2 cams) and the fact the camera kinda scuk, i cant take out the flim half way to insert the ISO400 one.
First of all, I don't know wat film u're using, but pushing from 100 to 400 is a 2 stop push, and u are not likely to get very optimum results with a 2 stop push, not to mention the only place to do a 2 stop push cheaply is RGB color (no affliations), and not a lot of labs will do push or pull processing well. (IF AT ALL!)

Secondly, no u cannot push / pull half a roll and develop the rest normally. You got to develop the entire roll. Technically, you can pull out the entire roll in a dark bag, snip the film at places where u know was shot with ISO 400, and develop those accordingly, but this is only possible if u do your own processing, and I doubt u'll be doing your own home colour processing if u're asking a question like this one :) Also, this is not a practical or feasible method since u would not know exactly where the part of the film was that was exposed with an ISO of 400 except by guessing.

The solution to your problem is to buy a film picker for about $15. This allows you to pull out the film leader from the canister even after your camera has rewound the film inside. Then you label the canister with the last shot count (say 24), pull in a fresh roll of ISO 400 film, shoot with that, and take it out when u're done with ISO 400. Mark the 400 film again with the last shot count (say 15), use the film picker to pull out the film from the ISO 100 roll, and put it in your camera. Put on the lens cap, switch to manual, change shutter speed to fastest possible speed, stop down the aperture to the smallest possible (typically f16 or f22), then press the shutter 24 times to advance the film to the last point where u shot, then advance 2 more times to ensure you cleared the last frame totally. Viola! Then continue shooting with ISO 100.

You may want to pull out the leader from the ISO 400 film as well so that u're ready to load when u need ISO 400.
 

Red Dawn

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#8
Hi

btw there ARE films that will allow you to shoot from ISO 100 to 800 without changing the film and those are the chromogenic black and white film from Kodak (TCN400), Ilford (XP2), Fuji (chromogenic Neopan) etc.

With Kodak TCN400 for example, if u read the box and official literature, you can do normal C41 processing with it up to ISO 800. For shots that are shot at ISO 100, you're get all detail in the deepest shadows without blowing highlights (within its limits of course) and for shots shot at ISO 800, you will also get detail if u expose correctly, but you need to print it accordingly to extract shadow detail.

it kind of behaves like digital sensor - the detail is there but u need to increase or decrease the "gain" to see all.

That's why some pple recommend shooting chromogenic for blackand white - you get a film that scans very well with ICE, GEM (compared to traditional b/w) and chromogenic film scans well and you can adjust contrast, curves etc to pull out all the detail. It makes for a more convenient workflow for b/w shooting, for those with scanners and digital printers at home.
 

CoExist

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#9
where do i get the film picker? does MS carry them??? hmm the fsilm alternative seems a gd catch but if is more costly than flim picker.. heh... i guess u know wad i wld get :D

coke21, the reason why im using or rather going to use 2 ISOs at a single roll is that im going mtn climbing, day time, i wld use ISO 100 and when it comes at night, i may not be able to have stable hands enuff for night shots. and thats also the reason why im using one cam, 2 will compramise my weight of my pack.

the picker sounds good....
 

Zerstorer

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Film pickers can be bought from Konota, Ruby, Cathay Photo..etc.
About $18-$20 for the blue Konica one.
 

coke21

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#11
CoExist said:
the reason why im using or rather going to use 2 ISOs at a single roll is that im going mtn climbing, day time, i wld use ISO 100 and when it comes at night, i may not be able to have stable hands enuff for night shots. and thats also the reason why im using one cam, 2 will compramise my weight of my pack.

the picker sounds good....
Why not just use ISO 400 in the first place?
 

CoExist

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coz may not be only using iso400 maybe iso 800 films? or even B & W ones... and the pic are too grainy to my preferance if i choose a high ISO
 

coke21

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#13
CoExist said:
coz may not be only using iso400 maybe iso 800 films? or even B & W ones... and the pic are too grainy to my preferance if i choose a high ISO

Don't understand what you mean by your first part.

As for grain. Try using Fuji superia 400 think its pretty good with very fine grain.
 

showtime

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#14
fujis range of ISO400 film is very versatile. low grain. if i can only bring one negative film, it would be superior 400.
 

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