Exposing for snow

colrehogan · Dec 17, 2007

I went out with a fellow photographer yesterday and was shooting snow. He was shooting digital and I was shooting a combination of HP5+ (whole plate) and Velvia 100 (35 mm). Now, my question is, should I have over or underexposed the snow to get it reasonably white? The question is for both b/w and color film.

He played with exposure on his digital and found that underexposure gave reasonable results. My limited experience of digital told me that it behaves similarly to slide film.

David H. Bebbington · Dec 17, 2007

Normally, placing snow in zone 7 will give a good result - in simple terms, take a reflected light measurement and open up 2 stops. This is not overexposure - it's correct exposure!

Regards,

David

BWGirl · Dec 17, 2007

I'd have to agree with underexposure. I love shooting snow. I'll also use a polariser depending on the light. If it's harsh, you really need a polariser.

Andy K · Dec 17, 2007

Would incident metering help?

snallan · Dec 17, 2007

Hi Diane,

If you were metering the snow, you will want to overexpose to get the snow white. Shooting based on the metered values will give you grey snow, to get a nice textured, white snow, you would probably give around 2 stops extra exposure for the HP5 (depending on your processing, possibly as much as three stops).

For the Velvia, I would probably overexpose by just one stop.

When you think about it, more exposure gives more density on the negative; which translates to less density (white) on the print.

Samuel Hotton · Dec 17, 2007

If you are using reflected meter readings try this.
If you are metering off of white snow, consider that white reflects 90% which is 5 times more reflection than that of a 18% grey card. So if you divide 5 into your ASA and set your meter to this new ISO and take your reflected readings off the white snow, your exposures will be the same as reading off of a 18% grey card. example: 100 ASA film. 100 divided by 5 = 20 ISO Set meter to 20 ISO and meter off of white snow.

OR, yes, you can use an incident meter.

Regards,
Sam H.

Andy K · Dec 17, 2007

I remember reading somewhere (probably here on APUG) that if you don't have a grey card or incident capable meter with you, you should be able to meter off your hand and open up one stop, because your hand* is one stop lighter than an 18% grey card. Or just meter off the snow and open up two stops.

*If you are caucasian, I don't know how that works for other skin tones.

colrehogan · Dec 17, 2007

Thanks for all the replies. The HP5+ will be developed in Pyrocat-HD. The Velvia will be done by a local lab. My b/w shots were shot with more exposure, so I hope I get some nice images. It was 23 F yesterday and kind of windy, especially for the last few shots when we were out in the open area of the park.

David Henderson · Dec 17, 2007

It depends on how you're metering. If you're pointing a reflective meter at the snow, you definitively need to give more exposure than the meter indicates to get the snow to look white. If OTOH you meter a scene that contains snow but other darker elements as well then its possible for at least some of that compensation to be inbuilt into the reading.

The extent of "over-exposure " you need will depend on how you want the snow to look. If you want to see detail in the snow then you need to give less exposure than if you want a pure white featureless blanket.

Finally it depends on what film you're using and its dynamic range. For B&W film I'd tend to "overexpose" snow by 2-2.5 stops vs a reflected reading of that snow to retain some detail; maybe three stops if I pretty much just want white. Velvia 100 has a much more restricted dynamic range, especially on the overexposure side and you can't just follow the same tactic. There 1 stop -again relative to a reading taken of that snow- more exposure will give you white with detail. 1.5-2 stops will be pretty much just white, and more than that will be clear film.

Using an incident meter on a contrasty scene with slide film wouldn't be my choice, though i'm sure lots of people do it.

A polariser can be helpful to reduce glare at certain angles, and reduce what can be a large difference in brightness between snow and the rest of your picture.

Lee L · Dec 17, 2007

My two incident/reflective meters show 2.67 stops difference between properly metered incident light and the reflected light off snow on an overcast day with very even light.

Snow tends to bounce fill light into shadow areas, so I usually only give 2 or 2.5 stops extra exposure to metered snow with normally processed B&W film. I'd probably treat metered snow adjustments differently depending on whether the film is more straight line like TMX or has a shoulder like Tri-X.

With color slide film, you have to know the film or bracket a bit.

Lee

thebanana · Dec 17, 2007

I have way more experience shooting snow scenes than I would like to and have always found that opening up 2 stops from the camera meter reading works well.

Bruce Osgood · Dec 17, 2007

I agree with what's been said so far but would like to add a wrinkle.

A lot of snow scenes will have a large/long range of tones and you may find greater than a paper can handle. Keep in mind you may want to adjust your development time downward to accomodate the high end and bring it down a tad.

ricksplace · Dec 17, 2007

thebanana said:
I have way more experience shooting snow scenes than I would like to and have always found that opening up 2 stops from the camera meter reading works well.

Right on. Up here, if you don't shoot snow, you only shoot outside during the summer. All two weeks of it.::rolleyes:

colrehogan · Dec 17, 2007

The b/w is destined for either normal silver printing, pt/pd printing or both.

dmr · Dec 17, 2007

This thread got me to thinking about this particular image, which I recently posted in a "winter" w/nw thread on "Another Network".

Granted, I'm looking at this on the flat-screen monitor here at work, which is not the best as far as viewing photos. My eyes do tell me that the snow portions are approaching overexposure. Using the color sampler they seem to be in the 235-245 range on R, G, and B. I really can't see that much detail in the snow. (The white of the off-dead-center sign is in the 240-ish range as well.)

Looking at the histogram, it really doesn't show a blow-out on the highlights. There's a teeny-tiny spike at the bright end, but it looks like most of the "energy" of the snow is in the 230-240 range here. The snow is definitely white and not grey.

This was, of course, metering with the Mamiya SD and centering the needle, for an averaging exposure.

I don't think overexposure of 1/2 stop would be advisable here, but I'm thinking that in similar scenes, maybe underexposing by 1/2 or 1 stop might put a bit more detail in the snow.

Comments?

johnnywalker · Dec 17, 2007

ricksplace said:
Right on. Up here, if you don't shoot snow, you only shoot outside during the summer. All two weeks of it.::rolleyes:

Or, as my mother used to say about northern Manitoba, "Eleven months of snow and one month of bad sledding".

Anyway, adding two stops works well, even a tad more if you're metering directly off the snow.

Sirius Glass · Dec 17, 2007

When my brother lived in Rochester New York for two years, he claimed that Rochester had winter and the 4th of July. Furthermore, some years the 4th did not come.

Myself, I liked Rochester and Calgary.

Steve

Lee L · Dec 17, 2007

I lived in Minneapolis for six years, three of them the heaviest snowfall years in the previous 100, IIRC.

The short summer joke I heard most there was that if summer came on a Sunday, you had a picnic.

And for dmr, snow in flat light like the shot you've posted has very little contrast, so it's tough to bring out structure and details.

Lee

Chuck_P · Dec 17, 2007

Just remembering that all reflected meters want to either reduce high value areas to middle gray or increase low value areas to middle gray will provide the answer. So if you accept a reflected meter reading of a high value scene such as snow, then the negative density for the snow will be that which will print the snow as close to middle gray as the meter could get it. It's been said, so allow for at least 2 extra stops of exposure (for added negative density in the snow) for the snow to be closer to white. No different really than photographing a white barn and exposing to ensure the barn develops to a density that renders it as a white barn rather than a gray one.

Chuck

Kilgallb · Dec 17, 2007

Snow on an overcast day reflects less than on a sunny day. I think you need to set snow to zone 7 on a sunny day and zone 8 on an overcast day if you want it to be really white, like your brain wants it.

copake_ham · Dec 17, 2007

Last Winter I shot this with Velvia 100 on the F5 using AF settings.

No grey snow.

This past week we were "fortunate" to get some snow this and I shot some more - will post later.

kjsphoto · Dec 17, 2007

David H. Bebbington said:
Normally, placing snow in zone 7 will give a good result - in simple terms, take a reflected light measurement and open up 2 stops. This is not overexposure - it's correct exposure!

Regards,

David

Yup, what David said... >>>> This is not overexposure - it's correct exposure!

Curt · Dec 18, 2007

Normally, placing snow in zone 7 will give a good result - in simple terms, take a reflected light measurement and open up 2 stops. This is not overexposure - it's correct exposure!

Correct; Fred Picker's book describes a horse that shows how exposure can make a black or white horse from a gray horse. The Ansel Adams book series also is a great reference, as is any good Zone System book. The system is good for something after all.

Lee L · Dec 18, 2007

Kilgallb said:
Snow on an overcast day reflects less than on a sunny day.

Please explain by what mechanism the light source changes the albedo of snow.

Lee

RobC · Dec 18, 2007

Unless the snow is in direct sunlight it will have a lot of blue light being reflected from it and even in direct sunlight it will be somewhat blue.
Where to place your exposure depends on the film type and where you are metering. I'll assume you are metering direct from the snow.
For slide film meter snow and then give 1 to 1.5 stops more exposure than metered. For colour negative give 1.5 to 2 stops more exposure than metered and for black and white film it will depend on what your film is calibrated to. Assuming you are using ilford recommended times, then give 1.5 to 2 stops more exposure than metered. If you have calibrated to zone system using a 10 zone system, then give 2 to 3 stops more exposure than metered.
For black and white, a light yellow filter will increase the contrast/detail in the snow. Don't forget to apply your filter factor if using one.
For colour film, a weak warming filter may help to remove any blue cast in the snow.

Exposing for snow

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