Working out development time with a scanner

[AnimalBones]

Hi, I am working out development time for a new film/developer combo (I like to work this out myself). Normally I would expose a grey card at zone VIII alternated with blank frames. I print until the grey card negative develops with a hint of grey. If this matches the point at which the blank frame prints max black then the development time is good. I have a Plustek 8100 scanner coming to try so was wondering about using that to optimise my development time. It's not a densitometer but has anyone used scanned negatives for the purpose of optimising development time and can give me hint as to how to go about this.

Thank you

 

[FruitFlakes]

With Vuescan you can tell it to sample a blank frame and then lock the exposure based on that blank. All subsequent frames will then use that as a baseline. You can then judge which of the Zone VIII shots meets your desired exposure/density.

 

[AnimalBones]

With Vuescan you can tell it to sample a blank frame and then lock the exposure based on that blank. All subsequent frames will then use that as a baseline. You can then judge which of the Zone VIII shots meets your desired exposure/density.

Hi FruitFlakes,

I'm not sure I follow. Your optimal Zone VIII shot (and therefore development time) depends upon the blank developed for the same time (and compared on printing). You therefore examine the Zone VIII shot and compare it to the corresponding blank but only one combo of Zone VIII/Blank will be optimal. How do you select the blank in your method and how does it relate back to development time?

Cheers

 

[FruitFlakes]

Hi FruitFlakes,

I'm not sure I follow. Your optimal Zone VIII shot (and therefore development time) depends upon the blank developed for the same time (and compared on printing). You therefore examine the Zone VIII shot and compare it to the corresponding blank but only one combo of Zone VIII/Blank will be optimal. How do you select the blank in your method and how does it relate back to development time?

Cheers

1. Sample the blank frame (assuming it's actually blank, i.e just the film base) with Vuescan. That helps Vuescan establish the black point for the entire roll. To do that you preview the blank frame, select the blank area, hit preview again, then scroll down and tick 'Lock exposure'. This tutorial is for colour negative scanning but it should get you set up for determining your film base exposure: http://benneh.net/techs hit/better-colour-neg-scanning-with-vuescan/ (remove the space since the forum sofware censors swearies).

2. Scan/Preview your Zone VIII shots and pick the one that looks best to you. I'd use the histogram that Vuescan gives you to determine that, just spitballing but I assume that the 'correct' frame will have a spike in the histogram in the 230-240 area for Zone VIII.

 

[AnimalBones]

1. Sample the blank frame (assuming it's actually blank, i.e just the film base) with Vuescan. That helps Vuescan establish the black point for the entire roll. To do that you preview the blank frame, select the blank area, hit preview again, then scroll down and tick 'Lock exposure'. This tutorial is for colour negative scanning but it should get you set up for determining your film base exposure: http://benneh.net/techs hit/better-colour-neg-scanning-with-vuescan/ (remove the space since the forum sofware censors swearies).

2. Scan/Preview your Zone VIII shots and pick the one that looks best to you. I'd use the histogram that Vuescan gives you to determine that, just spitballing but I assume that the 'correct' frame will have a spike in the histogram in the 230-240 area for Zone VIII.

Ah yes, that makes sense, thanks. I realised I also have a Stouffer step wedge with defined densities so I could also make a standard curve on the scanner using that and then take my various Zone VIII shots and pick the one with the correct density from that curve (1.2ish off the top of my head). I like your method as it compares against the film base, though.