Film latitude & use of an external light meter

[PhotorioNewbie]

I'm interested in learning to use an external light meter. I just watched a YouTube video on the subject, which impressed the heck out of me!

However: he assumes that you know what "tonality your film can hold". Is this the same as what people call "latitude"? And is it a spec that can be looked up, or is it the kind of knowledge that you only acquire through experience.

If it matters, my interest is B&W, 6x6 and 35mm.

 

[Trail Images]

OP- this looks like an early Ben Horne video to me from Cuyamaca area as I recall. I've not watched this video in a few years now. However, I know Ben is a big user of Velvia 50 and to answer a part of your question, yes. The tonality your film can hold I suspect is his reference to exposure latitude. In the case of V-50 it is very narrow with a + 1.5 and -1.5 for about a total of 3 stops. There is some fudging but extremely narrow and some can be rescued in PS on the backside.
Sorry, I cannot help with B&W, I only use V-50.

 

[Sirius Glass]

Yes the "tonality your film can hold" is film latitude.

Welcome to APUG Photrio.

 

[pentaxuser]

His Plus 2 and minus 2 seems to refer to Ansel Adams colours in terms of zones from pure Black to pure White and assumes that Zero is zone V so minus 2 is dark but with enough detail to have features which can be seen i.e. zone III and plus 2 is thus zone VII but I cannot be sure. Pity he didn't explain what me means more clearly.

pentaxuser

 

[PhotorioNewbie]

Thank you all. Is a film's latitude something that is maker/model specific? Is it a spec one can look up somewhere before buying the film? And does your intended output (size, chemistry, paper) come into play?

 

[tedr1]

Negative films (black and white and color negative) have more latitude than color transparency films (slides).

When the latitude is exceeded, which is not uncommon, three things can happen in various combinations: the shadows detail is lost (empty shadows); the highlight detail is lost (blown highlights); film graininess may degrade significantly.

The concept of exposure stops is useful in understanding film latitude. For example the use of an exposure meter might indicate the subject brightness range is 4 stops. All films can record this provided the exposure is adjusted correctly. When the subject brightness range is 10 stops then things become more tricky, some negative films might record this, but no paper or display can show ten stops. No transparency film can record 10 stops.

 

[Sirius Glass]

Each film has its own latitude.

 

[MattKing]

First, Welcome to Photrio.
Strictly speaking, a film's latitude refers to the range of exposures that can yield a desired result. A film with narrow latitude requires you to get the exposure right on. A film with wider latitude allows you to experiment with a range of exposures, which may lead to a range of suitable effects.
If there was a latitude "spec" it would describe how many stops of change of exposure - either reduction or increase - would still lead to something that you could use. It would most likely have to refer to a standardized image
Transparency still films tend to have limited latitude. This is due to the fact that they are designed to be shared via projection - they involve a single process which does not offer an intermediate step for further adjustment. And being designed for projection, they are inherently high in contrast, and high contrast usually means low or, more commonly, "narrow" latitude.
With transparency still films if you scan and print or post (or if in the past you printed using Cibachrome and masks), there is a bit more room to adjust, but you are definitely constrained by the nature of the original.
With a negative film/positive print workflow the potential for more or "wider" latitude is increased. Both the negative and positive materials are individually lower in contrast so they offer a wider range of exposures that will each lead to usable images. The total latitude of the combination is at least the sum of the latitudes of the two components.
If you wish to delve deeper, spend some time learning about film (and paper) characteristic curves. The way those are represented leads to a figure that looks like a tilted "S" where there is a small curve at the bottom (the "toe") a longer, straighter inclined section (the "straight line section") followed by a trailing away curve at the top (the "shoulder"). Roughly speaking, the film's contrast can be determined by observing the slope of the straight line section is, while the latitude can be at least approximated by observing how long and straight that straight line section is.