Fomapan 400, D23 development times, etc

[bryans_tx]

Hello,
What advice can you guys offer for developing Fomapan 400 in D23 ?
I checked the massive development chart, but I am unsure about the agitation for the 1:2 , 20 minutes suggested by the chart, as there were no notes.

thanks,
Bryan

 

[Andrew O'Neill]

Are you doing continuous or intermittent agitation? Box speed? If I were you, I'd go with 1+1 at 13:00, intermittent, 10:30, continuous (rotary). 20C.

 

[bryans_tx]

Yes hopefully exposed for Box speed of 400.
Not rotary.

Patterson Tank.

If I go with 1+1 at 13 minutes intermittent, what do you suggest for the intermittent agitation cycle ?

thanks VERY much!

 

[Andrew O'Neill]

Yes hopefully exposed for Box speed of 400.
Not rotary.

Patterson Tank.

If I go with 1+1 at 13 minutes intermittent, what do you suggest for the intermittent agitation cycle ?

thanks VERY much!

I always agitate 5 sec every minute, regardless of film type.

 

[Rick A]

I always agitate 5 sec every minute, regardless of film type.

Same here.

 

[bryans_tx]

ok thanks very much!

 

[bryans_tx]

OK so Negatives are hanging and drying, and there are actually images on the film lol!
Thank you for the help.

 

[M-88]

Bear in mind that actual speed of this film is somewhere around 250, not 400, so exposing and developing it at EI400 is a slight push. I got best results from Foma 400 when exposed and developed for EI200.

It's also one of those films I will never buy again.

 

[bryans_tx]

that is good info, thanks.

 

[traveler_101]

I got best results from Foma 400 when exposed and developed for EI200.

It's also one of those films I will never buy again.

I’ve wasted a lot of time with it, no more. One time I got good results was shooting at 200 on a heavily overcast morning developed in D-76 1+1

 

[M-88]

I’ve wasted a lot of time with it, no more. One time I got good results was shooting at 200 on a heavily overcast morning developed in D-76 1+1

Oh well, it would have been easier, had they written an actual sensitivity on the box, not 400. Foma 400 is the worst of their bunch. 200 is fine and 100 is the best. Abut even that one performs with random precision.

I still have some good shots from Foma 400, but success to fail ratio is too high.

Edit: too low, I mean.

 

[albireo]

Foma 400 in 120 is one of my favourite films. It needs to be exposed and developed with respect for best results, and I've found following the manufacturer's spec sheets for a target gamma =~ .58 gives me great reproducible negatives optimised for my workflow.

It looks awesome in Fomadon LQN, Fomadon Excel expecially, but I've gotten some great results with it in D23 1+1 too.

Ever since fine tuning Foma 400 I just can't get back to run-of-the-mill 400 ISO film like Hp5 or TRI-X. Foma 400's spectral response is just unique. Gorgeous film, I burn some 10 rolls per month in my Fuji GW690.

 

[pentaxuser]

Foma 400 in 120 is one of my favourite films. It needs to be exposed and developed with respect for best results, and I've found following the manufacturer's spec sheets for a target gamma =~ .58 gives me great reproducible negatives optimised for my workflow.

albireo, what film speed do you expose it at? Thanks

pentaxuser

 

[albireo]

albireo, what film speed do you expose it at? Thanks

pentaxuser

Hi Pentax

https://www.foma.cz/en/fomapan-400

Page 2, first column of graphs. I will generally interpolate the graphs for a target gamma of .58 to reach a starting point. So eg 200 for D76, 250 for Excel, 250/320 for LQN. Then I will adjust based on how I meter and if I feel the contrast of the scene might require an amount of pulling or pushing.

 

[pentaxuser]

Hi Pentax

https://www.foma.cz/en/fomapan-400

Page 2, first column of graphs. I will generally interpolate the graphs for a target gamma of .58 to reach a starting point. So eg 200 for D76, 250 for Excel, 250/320 for LQN. Then I will adjust based on how I meter and if I feel the contrast of the scene might require an amount of pulling or pushing.

Thanks I wonder if you can help me a little more here with how to read the graphs If we take D76 at 20C then is the case that the top curve indicates the film speed at various development times so to get to 200 the time is just over 7 mins?

How do I work out the Gamma at that development time? Do I just go straight down from the 200 speed? If so this gives me a Gamma of about 0.62 and not 0.58 but I may be making the wrong assumptions about how to read the graphs

Thanks

pentaxuser

 

[albireo]

Thanks I wonder if you can help me a little more here with how to read the graphs If we take D76 at 20C then is the case that the top curve indicates the film speed at various development times so to get to 200 the time is just over 7 mins?

How do I work out the Gamma at that development time? Do I just go straight down from the 200 speed? If so this gives me a Gamma of about 0.62 and not 0.58 but I may be making the wrong assumptions about how to read the graphs

Thanks

pentaxuser

Hi

The way I do it is to *start* from the gamma I wish to achieve. See example below for Fomadon LQN.

In this example, let's say we wish to aim for a gamma =~ .7 (this is extremely high contrast, way too high for scanning, and I'd imagine also high for wet printing - it's just an example).

Follow the path traced by the red arrow. We start at (1), on the vertical axis on the right. We trace a horizontal path to intersect the gamma curve. At the intersection (2) we'll trace a vertical line to intersect the 's' curve at (3). Starting from (3), a vertical line down towards the horizontal axis will indicate a dev time estimate, whereas a horizontal line towards the vertical axis on the left will indicate the film speed achieved.

For the example above, if we are happy with a gamma =~ .7, we will achieve a speed of 320 and development will require approximately 11 minutes.

 

[pentaxuser]

Thanks albireo. Based on what you have described I think I got it correctly in my assumptions but I got the Gamma as 0.62 rather than 0.58

Your objective of 0.58 seems low compared to the contrast that Ilford and Kodak suggest but of course each of those companies use a difference index( Gbar and Contrast Index respectively) from that of Gamma and in turn each one is different from the other

I have asked what the relationship is between GBar and C.I. in the past but not between Gamma, C.I. and Gbar. So can I ask you what it is i.e. in Gamma terms what does a Gamma of 0.58 equate to in both the other terms?

It may be that a Gamma of 0.58 is right for scanning but not ideal for darkroom printing where it should be higher and is what I do but again I don't know.

So you or anyone with answers to these questions is welcome to respond

Thanks

pentaxuser

 

[albireo]

I have asked what the relationship is between GBar and C.I. in the past but not between Gamma, C.I. and Gbar. So can I ask you what it is i.e. in Gamma terms what does a Gamma of 0.58 equate to in both the other terms?

The gamma is the measure of the slope in the linear portion of the curve. I believe that the CI is the average slope based on measurements taken at several points of the curve, according to some criterion. I am not familiar with the other metric you mention. I'm sure someone else will chime in.

 

[pentaxuser]

The gamma is the measure of the slope in the linear portion of the curve. I believe that the CI is the average slope based on measurements taken at several points of the curve, according to some criterion. I am not familiar with the other metric you mention. I'm sure someone else will chime in.

Thanks. Yes it is important that somebody does since otherwise reading a Foma graph with Gamma does not have a good comparison in Kodak or Ilford terms

It's a bit like someone who only ever has used Fahrenheit using a chart in Centrigrade and trying without knowledge of the relationship to compare what that means in terms of Fahrenheit

pentaxuser

 

[bryans_tx]

very educational.