[butangmucat]

Hello,

I am experimenting with Portra 400, the goal is to shoot this film at EI 500-640 to give some extra speed, and would eventually consider using it up to EI 800-100 range. I would like some suggestions on how to develop the film under these two conditions. I am more interested in the EI 500-640 range as this allows me to no longer stock Portra 800 and Lomography 800. I've heard that for 800, Portra 400 does well with no push, and for 1600, push 1 stop would enough. I am especially interested in that, since pushing film in my preferred lab here in the US adds a surcharge, and pushing C-41 film is not available from my preferred lab in China.

Sincerely

[pres589]

There's some tidbits of information about pushing C-41 via stand development. I don't dev C-41 myself yet but have considered starting and would love to explore that method.

Not sure how useful this reply is. Hope you can figure something out.

[twilhelm]

I haven’t pushed Portra 400, but with Ektar 100, I’ve been able to push it to 200 with standard development and not see a difference.

Note: I am developing at home and my chemicals were mixed that day.

[Digitalis]

Negative films are pretty forgiving - you can pull them several stops without issue, pushing film involves more compromises with image quality the further away from the box speed you get. Fortunately box speeds on films are only recommended values, that when the film is developed as standard the negatives will reach a specific density and contrast. The density and contrast will change with each stop you diverge from the recommended value, if you keep your expectations to modest levels you will get something usable. I've seen people push T-max 400 to 6400 and complain that their images looked like they were shot in a snowstorm....

[officiousbystander]

Negative films are pretty forgiving

This is a useful overview of Portra 400 latitude.

You Tube

You Tube

[tuco]

With the latitude of Portra 400, an exposure index of EI 500 is pretty much unnecessary and a moot point. That said, you can extrapolate the development time increase needed from the following Jobo C-41 Press Kit instructions on the subject of push processing:

1-Stop Push: Increase development time by a 1.25X factor
2-Stop Push: Increase development time by a 1.5X factor

EDIT: For EI 640 I'd just round to EI 800 and push 1-Stop.

[Wheatfield]

Hello,

I am experimenting with Portra 400, the goal is to shoot this film at EI 500-640 to give some extra speed, and would eventually consider using it up to EI 800-100 range. I would like some suggestions on how to develop the film under these two conditions. I am more interested in the EI 500-640 range as this allows me to no longer stock Portra 800 and Lomography 800. I've heard that for 800, Portra 400 does well with no push, and for 1600, push 1 stop would enough. I am especially interested in that, since pushing film in my preferred lab here in the US adds a surcharge, and pushing C-41 film is not available from my preferred lab in China.

Sincerely

My (extensive) experience with C-41 is that it doesn't push process. I ran a number of tests quite a few years ago that indicated push processing it was a wasted effort.

[pres589]

So what's going on with examples like this?

Mat Marrash: Pushing Kodak Portra - The Film Photography Project

Etc etc etc. There's a lot of folks putting info & images online concerning push processing. What happened when you tried pushing c-41?

[Mr Bassie]

So what's going on with examples like this?

Mat Marrash: Pushing Kodak Portra - The Film Photography Project

Etc etc etc. There's a lot of folks putting info & images online concerning push processing. What happened when you tried pushing c-41?

I guess you're replying to Wheatfield. I think the link you posted validates what he said. My understanding is that Wheatfield means that you can shoot Porta 400 at 800, 1600, etc and just process normally with no push. The link you gave shows a photographer who did just that and got great results. YMMV

[pres589]

Ooh, yeah, good call.

I should order a c-41 dev kit and try to mess around with this myself and see what kind of results I can get.

[Mr Bassie]

Ooh, yeah, good call.

I should order a c-41 dev kit and try to mess around with this myself and see what kind of results I can get.

Yes you should.

It has certainly inspired me to go out and shoot some Portra.

[jcdoss]

Found this today. Haven't read yet, but thought of this thread immediately...

Pushed to the Limit: Kodak Portra 3 Stops Over

[pres589]

It shows some results that are kind of not so hot and doesn't give information about how he altered the development process to achieve a push. The article does include a diagram with times used during normal machine processing of C-41 but doesn't tell us how he did it differently at home.

This is something I've tried to do, the telling of times and concentrations and such, in my Clayton F76 thread. If nothing else, it's started to become a quick and useful reference for myself to use.

[ChrisPlatt]

Your desire to standardize is understandable but if you really require the extra speed
I suspect it would be simpler to continue using Portra 800.

Chris