Contrast boost with 120 Acros

[surfotog]

I'm going to shoot some plant studies this weekend in very low contrast lighting with Fuji Acros in 120. The only developer I have on hand is Classic F09 ( Calbe R09). The "standard" dilution is 1:40. Should I try a higher concentration (1:20), increased development time, or both? Thanks for the help.

 

[philbed]

Do not change the way you develop your film. If you are happy with the 1:40 dilution keep it. If you want more contrast, you need to increase your development time. It's similar to "push" your film speed. For instance, my time for Acros in DD-X 1:6 normal contrast (SBR 7) is 7 min. For a low contrast subject (SBR 5) my time is 14 min and film speed +1/3 stop. You have to make some test to adjust your time. Hope it helps.
Philippe

 

[edtbjon]

You are on the right track about adjusting contrast with developing. Also, Philippe is giving good advice, but I think that his adjustment is a bit too much. I would say that some 25-40% should be enough, but that also depends on how flat the light really is.
To repeat what Philippe says, don't change anything else in your developing. I.e. the same dilution, same temperature, same agitation scheme, same agitation intervals etc. ... If you have the possibility, shoot an extra roll of film at the scene and develop that one first (or even half of it first! (hint: scissors)) to see if you have got your dev-time adjustment right.

//Björn

 

[surfotog]

Thanks for the responses. Perhaps I should have been more specific in my original post.
It's been several years since I've done any B&W developing. I returned from the digital world over the winter, working on a project in color. Now, I want to get back into B&W, so I have no set procedure for developing. I have not used the Acros/F09 combination before. It was my understanding that one of the benefits of the Rodinal family of developers, was that one could alter contrast by using different dilutions, higher concentrations for greater contrast, very dilute concentrations for more of a compensating developer.
That said, the light will be very flat. I also have some Rollei ATP in the freezer, which of course is inherently contrastier than the Acros, but as I'm still in the experimenting stage, I thought I'd use the much cheaper Acros.

 

[david b]

Pushing film always increases contrast, so why not shoot it at 200 and develop a little longer?