Mortensen's 7D negative

[olk]

olk submitted a new resource:

Mortensen's 7D negative - Mortensen 7D negative

Hi,
I don't get the steps required for making a 7D negative.

7D negative means measuring the lights and underexpose and overdevelop the film.

If a scene has a contrast range of 3 stops how do I adjust the eposure?
Do I have to underexpose by 2 stops (400 ISO box speed film exposed with 1600)?
But what about measuring the lights? If I measure the lights with the light meter (== Zone V) with the ISO 1600?
The I would have 4 stops underexposure if the light would be Zone VII in real but...

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[johnnywelchfilm]

Hi olk,

Some thoughts of my own.

So, Mortensen's 7D neg is underexposed and overdeveloped.
I would say that the idea here, would be to capture more gradation in the highlight tones by placing them lower on the Zone range (so that they don't block up). Then with overdeveloping, get the shadows up to a usable level without them disappearing altogether.
It also would depend on which film you were using, and also the exposure range of your scene, as to whether you would underexpose -2 stops, then overdevelop two stops.

Developing
What you need to know really first, is your normal developing time for your film (N).
Shoot a test with a grey card, assigned on Zone V.
Then you need to establish what would be your N+1 and N+2 developing times. Which means, your developing times to increase the exposure by one stop, and two stops respectively.

As a guide you can start here, and adjust for your developer/film combination with testing:
N+1 Developing time x1.25
N+2 Developing time x1.5

Compare the N+1 and N+2 tests with your N negative, to see if the grey cards match up to Zone V. You can shoot one reel of Zone V exposures and cut it into four strips and develop with the guide times above, then increase by one minute if the negative still looks under exposed.

Shooting
Then when you have achieved your N+1 and N+2 times, you can shoot underexposed 1 or 2 stops.
For one stop underexposure, you can double your ASA setting on the camera, e.g. ASA 100 film, metered at ASA 200.
Two stops: ASA 100 film metered as ASA 400.

So in terms of zones, say for e.g. (N+2) if the skin was metered at Zone VI, white shirt at Zone VII, background at Zone V. Then in reality Skin is captured at Zone IV, White Shirt at Zone V, BG at Zone III (and overdeveloped in order to reach roughly zones VI, VII and V again in the negative).

 

[Alan Johnson]

See the example "Amy with ribbon" here:

Robert Balcomb – TheScreamOnline

thescreamonline.com

Mortensen was a portraitist of course, the method was only intended for this or similar.
Development was to expand the highlight tones.

Mortensen Revisited

He was pre-"Zone system", developed by his rival and claimed by some users to include him as a special case.