i recently switched devolopers, so i have a new dilution and normal time, and i shot some film before i did the testing @ a different film speed, how can i figure out what time to process them at

[megan_griffith]

<p>hello, i recently had to switch devolopers, so i did the zone testing over again and i have a new normal time and a new dilution (at a different film speed : 250) i shot a couple rolls before i did this switch.. one roll is a +1 shot at 400, the other is a +2 @ 400. my new time/dilution was all determined @ a film speed of 250, ( i use ilford hp5 400)how can i figure out what time i should devolop these rolls of film at? i would greatly appreciate any help. thanks,megan </p>

[bob_sunley]

<p>What developer were you using, how did the negatives turn out? What is the new developer?</p>

[megan_griffith]

<p>hello, i was using d-76(accurate custom blend brand)@1;4 with a film speed of 400 and now i am using claton f-60 @1:10 with a film speed of 250. i got great results with both of them but i couldnt find my old devoloper at any of the photo supply stores near me, so i switched and did all the testing with the new dev. and my images came out great. i just dont know how to figure out what time i should use to devolop my negs shot at a film speed of 400 with my new normal time (7min @1:10) any ideas??</p>

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[jay_de_fehr]

<p>Megan,</p>

<p>I'm confused. You were using D-76, so D-76 is your "old developer" you can't find? And Cayton F-60 is your current developer? You used D-76 with an EI of 400, and F-60 with an EI of 250? Now you want to develop film exposed at EI 400 with F-60? You want to know how much longer to develop in F-60 for film exposed at EI 400? If I'm getting this right, your EI 400 film is underexposed for your developer, and extending development time will only serve to increase contrast, and won't secure the shadow detail you presumedly tested for. That being said, a 20% increase in development time is typical for a one stop push, so try 8:30. Good luck!</p>

[bob_sunley]

<p>Duh, asa 400 film properly exposed at 400 should be developed as per the published times and dilutions.</p>

<p> Sounds like you are pretty new at this, do you have a densitomer to check your negatives for correct densities or are you just eyeballing them? Over exposing and pulling the dev time may not get you the best negs in the world either.</p>

<p> </p>

[User_502260]

<p>There is more than one film speed (exposure index) setting and developing time combination which will give good results. The combination will depend, in part, on what kind of lighting you have. Some people like to downrate a 400 speed film to 250 if the light is very contrasty and then shorten the develping time a little. With flat light some people like to uprate the film slightly and increase the developing time. If you are using the Zone System with sheet film then you can customize exposure and development for each shot. This isn't practical for roll film unless you shoot the whole roll in the same kind of light. The Clayton F60 container shows developing times for the 400 speed b&w films at 400. These are all, of course, just starting point times because you may be scanning the negatives or printing them with either a diffusion or a condenser enlarger.</p>

[lowell_huff1]

<p>MEGAN send me an email and i will return my development charts. askus@claytonchem.com</p>

[megan_griffith]

<p>hello again, if each stop is double the light and my new dev. dilution was based on a iso of 250 ( with 400 iso film) shouldnt i just subtract 1 stop from my calulated exposure ( the rolls i shot were exposed @ an iso of 400 instead of 250) thanks again for your help</p>