Incident Meter and Snow

Darkroom317 · Jan 30, 2010

I went out today with my RB67 and took photographs of the snow using a Sekonic incident meter. I set an exposure at EV14 and exposed it at EV12 in order to get white snow. However, I am now wondering if I overexposed it. Is it necessary to compensate in order to avoid 18% grey snow with an incident meter or not? If the negatives are indeed overexposed, I would of course need to compensate in the development. The film is FP4+ and the developer is D-76. Any suggestions?

frank · Jan 30, 2010

3 stops over-exposed. With an incident meter and snow, one can reduce exposure by one stop to preserve detail in the snow. It's a reflected light meter reading of snow that should be adjusted as you did.

2F/2F · Jan 30, 2010

When you are using an incident meter, what you are doing is placing middle grey. Therefore, within the contrast range of the film, no adjustment is necessary. Things fall into place around middle grey, and if they are too far away from a mid tone for your particular film to capture with texture or detail, then they are either black or white. You can manipulate what extremes the film can capture via deviations from the norms of exposure and development, but unless you are doing this, there should be no exposure adjustments when using an incident meter.

So, yes, your negatives are overexposed by two stops.

The contrast within the compositions (coupled with what you want from the photos, of course) will determine what you should do in development to help compensate for the overexposure.

It is also possible that you picked up some "extra" light from the snow if it was a clear day and you did not point the meter directly at the light source (Sun), but at the camera lens. In that case, your meter thought there was more light than there actually was, and told you to underexpose a bit. If so, you are perhaps only 1.5 stops overexposed.

2F/2F · Jan 30, 2010

frank said:
3 stops over-exposed. With an incident meter and snow, one can reduce exposure by one stop to preserve detail in the snow. It's a reflected light meter reading of snow that should be adjusted as you did.

Making that adjustment diminishes tonality by a stop across the entire negative. This is not necessary, as you can simply underdevelop the negative to preserve detail in the snow without lowering every other tone in the picture. To get what you describe, you can simply darken the print. No need to underexpose the whole neg to do it.

Darkroom317 · Jan 30, 2010

Forgot to mention the conditions. It was over cast.

2F/2F · Jan 30, 2010

Darkroom317 said:
Forgot to mention the conditions. It was over cast.

In that case, the meter reading should have been dead on no matter where you pointed it (at the haze/fog/clouds that were providing the illumination, or at the camera). You are two stops over.

I would develop minus one or normally, as it was not a high-contrast lighting situation anyhow (though some compositions in low-contrast lighting conditions can still have a wide luminance range). FP4 does not easily block up in the highlights. I might do a one stop pull, but not two. If it was a clear snowy day, I might pull two.

Darkroom317 · Jan 30, 2010

Thanks

Sirius Glass · Jan 30, 2010

As I posted in the beginning of the thread, over expose by two stops in the bring sun for reflectance meters in snow scenes when the percentage of snow areas is large.

Let me expand this with the generalized rule.
If a large portion of the scene is bright white, example snow, open the aperture two stops [smaller f/numbers].
If a large portion of the scene is bright black or very dark, example night photography, close the aperture two stops [larger f/numbers].

Steve

2F/2F · Jan 30, 2010

Good rules of thumb for reflected light meters, but the OP is talking about an incident meter, with which such fiddling is not necessary.

Darkroom317 · Jan 30, 2010

So, development at EI 80 would probably be best, right?

2F/2F · Jan 30, 2010

I would say that the Ilford times for EI 50 (or do they list them for 64?) would work fine if you want to do a one stop pull.

FYI, only exposure is made "at" an EI, not development. Development is made "for" an exposure that has been made "at" a certain EI. EI means "exposure index", and development in and of itself has nothing to do with this.

Darkroom317 · Jan 30, 2010

I meant the time for film that was exposed at EI 80. Looking at the massive development chart, they only list 50 and 80, no time for 64.

2F/2F · Jan 30, 2010

Darkroom317 said:
I meant the time for film that was exposed at EI 80. Looking at the massive development chart, they only list 50 and 80, no time for 64.

IMHO, the best thing you can do with the Massive Development Chart is forget that it exists. Who knows who puts the information into that database. Much of it is straight from the manufacturer's anyhow, and I would rather get that information first hand from Ilford publications than second hand, with the possibility or transcription/data entry errors.

Where the Massive Development Chart might provide a good starting point is with an "experimental" or an "esoteric" combination. The problem with the chart, however, is that there are no standards. Someone might call their development good, when it is really too high or too low in contrast...not to mention what their metering techniques might be!

fschifano · Jan 30, 2010

Ain't that the truth!

Stephen Benskin · Jan 31, 2010

2F/2F said:
IMHO, the best thing you can do with the Massive Development Chart is forget that it exists. Who knows who puts the information into that database.

That can't be emphasized enough! Well said.

Darkroom317,

You might want to develop the negative around normal and simply print down the overexposure.

markbarendt · Jan 31, 2010

You may try just reducing your agitation to protect the highlights.

My norm is to overexpose from box a bit but this is purely my personal preference and the result of my testing and exposure methods. I use Xtol and typically run N+1 time with reduced agitation, 1 inversion every 2 minutes instead of 5 inversions every 30 seconds.

See this article (there was a url link here which no longer exists) this article and Kodak's directions for controlling contrast in the Xtol tech data sheet (J-109) are where I got the idea.

Shoot a test roll exposed similarly (to make an after the fact clip test) cut it in several pieces, develop 1 piece normally, one piece with just reduced agitation, one piece reduced time with normal agitation... Keep playing until you get the contrast you like.

Incident Meter and Snow

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