How much extra time for pushing C41...

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Lee
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I'm sure someone on here knows the answer...
I've shot a roll of Agfa 200 @ 400 ISO, so, how much do I need to add on to my developing time?.
To add, that the film didn't fully rewind either, which I didn't know until the back had been opened doh!.... so does that make any difference, or will I just lose x amount of frames?.
 
I'd go with 30%, pushing and pulling is not an exact science at the best of times. 30% is recommended for a 1 stop push in The Darkroom Handbook.
 
I wonder if there's a difference between colour and black and white - and if so, which the Darkroom Handbook is discussing? The Darkroom Cookbook suggests 25%+ for a one stop increase, but is clearly considering only black and white.

Now, I've never ever processed a colour negative film, so I can't speak from any experience; and the latest versions of the books I generally regard as accurate have dropped the film processing details. Going back to the 6th edition of Langford's Advanced Photography (the most recent one I have that discusses film, date 1998) there is information on push processing C41 films. The caveat is that it is "only suitable for film types specifically intended to give acceptable results when speed enhanced in this way". The variation in the time of colour development for 1 stop is given as +15.4%, and for 2 stops +31%.

I offer no opinion on the usefulness of this.
 
I wonder if there's a difference between colour and black and white - and if so, which the Darkroom Handbook is discussing? The Darkroom Cookbook suggests 25%+ for a one stop increase, but is clearly considering only black and white.

Now, I've never ever processed a colour negative film, so I can't speak from any experience; and the latest versions of the books I generally regard as accurate have dropped the film processing details. Going back to the 6th edition of Langford's Advanced Photography (the most recent one I have that discusses film, date 1998) there is information on push processing C41 films. The caveat is that it is "only suitable for film types specifically intended to give acceptable results when speed enhanced in this way". The variation in the time of colour development for 1 stop is given as +15.4%, and for 2 stops +31%.

I offer no opinion on the usefulness of this.

Stephen.... thank you for your reply as well.

I've not pushed film before, so never had to develop one.....I developed the roll last night.... now although the back had been opened as the film had stopped rewinding, when I opened it I saw it hadn't,(I then closed the back and did the rest in the changing bag) I assumed I'd get 'some' frames with images on.
Well... I added on an extra 58 seconds to my time.... the roll is totally dark, so no images can be seen, although there is a faint number 2 indicating where frame 2 would have been.
 
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