Pushing/pulling C41 films

It's not really pushing or pulling if you don't change the process. It's just under or over exposing.


Steve.
 
I think you've missed the point mate...

I think what silverprint mean is that you simply underexpose/overexpose by a stop and just tell them what you've done and the 'process' of sending away the film for developing doesn't change.

They'll however need to process it differently.

The benefits of pushing and pulling film is, say for example you have an ISO 100 film and you need to take photos at a gig, you can push it 3 stops to ISO 800 and get a usable ISO from it, and then they'll just drag the film back. Because film has a much higher dynamic range to digital, the results won't be too bad.
 
You can under or over expose most negative films, black and white or colour and still get a good image.

With mini-lab processed colour, the printer is set to compensate and produces an acceptable image. Most colour negative films are better with a bit of over-exposure in my opinion.

If you are doing your own printing then you can decide how it looks.

Negative film has enough latitude to still record a full range of tones without losing too much shadow detail or blowing out the highlights too much.

Slide film and digital are not so forgiving. A slide is intended to be the final product so there is not really any room for error. Digital also reacts like slide film in that once you have blown out the highlights, there is nothing you can do to get any detail back.

As a trial, load up a roll of ordinary C41 colour film, set the camera to manual and take a series of pictures of the same image in the same light ranging from four stops under exposed to about six stops over exposed then get some prints from a mini-lab. You will be surprised at how many of them come out looking fine.


Steve.
 
If you are only scanning then the exposure will control how the shadow and highlight detail is handled.

If you under expose you will lose shadow detail. When you adjust your scan to make the image look normal again it will not bring out the detail you have lost because it was not there.

If you over expose, shadow detail will increase. this is because you are moving the shadows up the tone curve a bit.

Logically thinking, the highlights will suffer with over-exposure and in the case of a scan, this is true. however, This is usually more to do with the scanner than the film as the highlight is still there in the film but it is more difficult for the scanner to record it.

The same test I mentioned above but with scans instead of prints will show you what is happening and would have an added advantage in showing you how you should rate the film to get the best results from your scanner.

Do a search for 'Personal Film Speed'. there are lots of articles which describe it better than I can. Basically, it's a method for determining the best film speed to use for the methods you employ in metering, developing and printing. Whilst it's geared towards self developing and printing optically, it should still give you some understanding of what's going on and some of it will still be relevant to a standard process and scanning method.


try this one: http://www.halfhill.com/speed1.html



Steve.
 
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