correct exposure to get a Zone VIII negative

Nice. I'm thinking in build a density curve from zone I to VIII. It's the homework for today

How did you do your Zone I exposure test? Do the Zone VIII the same way but give 3 stops more time rather than 4 stops less time. You did not do your Zone I test yet?? IF not, you need to, as you know any change to your exposure index will change the density of Zone VIII irrespective of development time.

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Originally Posted by ic-racer

How did you do your Zone I exposure test? Do the Zone VIII the same way but give 3 stops more time rather than 4 stops less time. You did not do your Zone I test yet?? IF not, you need to, as you know any change to your exposure index will change the density of Zone VIII irrespective of development time.

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No I'm in the process, but I have to do it in the opposite direction, zone I is less time and zone VIII is more time. By the way, I'm using a Holga pinhole lens for Nikon, so I have to shoot and develop a roll for each test. So for a Zone I test I have to give 1/16th of the time needed for Zone V. The sequence for a full zone I to zone VIII should be the time exposure for zone V equals to 1 zone I 1/16, II 1/8, III 1/4, IV 1/2, V 1, VI 2, VII 4, VIII 8

Right?

I might interject here to say that, if using panchromatic film, you will also need to account for reciprocity failure. Some films require less than others, for instance Fuji Acros.

Good luck on your project.

~Joe

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Originally Posted by RalphLambrecht

sounds alright. i look for zone viiito develop to a density of 1.29.

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For what kind of film Ralph?

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Originally Posted by Joe VanCleave

I might interject here to say that, if using panchromatic film, you will also need to account for reciprocity failure. Some films require less than others, for instance Fuji Acros.

Good luck on your project.

~Joe

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I´m working with HP5+ developed in D76 1+1 for 11:30 mins. at 20º C. I made a roll with the exposure meter set at 125 ASA, thinking in the reciprocity failure. It is still washing, but, in an eye inspection I found it weak. I´ll measure it tomorrow when it´s dry, then I´ll know if I have to give longer exposures or give an stronger development, or both.

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Originally Posted by Chan Tran

For what kind of film Ralph?

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Maybe you mean to match what kind of paper or enlarger?

yes, but don' ignore the reciprocity compensation.

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Originally Posted by ic-racer

Maybe you mean to match what kind of paper or enlarger?

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for what kind of film Tri X, HP5 ??? that the zone VIII would have density of 1.29? I checked characterisitic curves of many film and found that it also depend on how the film is developed. so the question is what type of film and what the development time would yield a density of 1.29 for zone VIII exposure?

for any and all fims!