4x5 Provia 100F pushing and long exp. question

[john mackay]

Hi,

 

Hope someone can help with this. As a new LF shooter I notice that

Fuji doesn't make their Provia 400 in sheet. I have made a search of

the forums and google groups and it appears that most people are

satisified with a 1-2 stop push of Provia 100F.

 

I have also noticed that many astro photographers are comfortable with

its long exposure response in both 100 and 400 35mm/120 roll-film

varients.

 

However, what I don't know is what happens if I combine both ie. push

Provia 100F sheet to ISO 400 and then long expose for several hours.

 

Has anyone tried this and what was your experience ie. contrast, color

shifting, filtering advice etc?

 

Cheers...John.

[jeff bishop]

I've accidently exposed a roll of Provia as iso 200 once. Developed it myself, as usual but (if I remember correctly) an extra 1/2 minute in the developer. I've no idea about 2 stops, but 1 stop was no problem at all. It came out beautifully.

 

Exposing for several hours? That would offer the greatest problems. Just figuring reciposity error would be a challenge.

[john mackay]

I'm only looking at doing 6x enlargements max. from these shots so I'm not too worried about any moderate increase in grain or even reciprocity failure for that matter. It will be astrophotography so I'm not even too worried about tonal loss.

 

My main concern is the potential colour shift through such a long exposure and trying to calculate filtration. Apparently, Provia 100F can suffer a green shift with longer exposures and I'm not sure if this is something I can non-destructively correct for in PS or whether I need to add magenta filtration at the camera.

 

Thanks once again for your help.

 

Regards...John.