What Is Slide Film?

A newcomer to film messaged me on Instagram to ask me a few questions about film, and they asked about expired film. I of course let them know that 99% of film in my store is fresh, and sourced from official film company distributors, but from time to time I do carry some expired film, which I mark extremely clearly as being expired.

I mentioned that I currently have some (barely) expired slide film in the store, and the person asked me what slide film was, since they hadn’t heard of it. This makes sense, because it’s not the most common thing these days, so I ran it down for them.

I’m basically going to paste what I told them, so I don’t cover the entire history of slide film, or the different sorts of slide film that have existed over the years, etc. I was just concerned with explaining what is relevant about E-6 slide film today, in 2019.

Here’s what I said:

So for slide film: You know how there is Black and White film, and then also Colour film? Well there’s also a third kind, called Slide film.

The difference is that NORMAL colour film, the stuff everyone just calls “colour film”, is technically called colour negative film.

When you get colour negative film developed, the colours are inverted – dark things are light, light things are dark, and there’s an overall orange colour cast to it.

With slide film, once you get it developed, it looks correct – there’s no orange cast to it, and everything is the correct colour. In the old days, people would get all their slide film put into little cardboard mounts and show it on their wall using a slide projector.

These days though, slide film is much less popular, and because of that, it costs more per roll. It’s also a lot harder to find somewhere to develop it. Developing it yourself is possible, but the chemicals are more toxic than C-41 chemicals (which are used to develop colour negative film) and also E-6 slide film development kits are harder to get in Canada.

The other thing about slide film is that you have to be a lot more careful about your exposure. When you’re using colour negative film, you have a fair bit of exposure latitude. If you under-or-overexpose your shots taken with normal colour film, they’re going to be a lot more usable than if you do the same thing with slide film.

The other downside to slide film is that it has a significantly narrower dynamic range than colour negative film. This means that if you’re photographing a scene with some very dark areas, and also some very bright areas, the slide film will have a tougher time capturing the extremes, and you might even get very blown out bright areas, or the dark areas might lack detail.

An example of this might be if you were photographing a landscape with a bunch of dark pine trees, and a bright blue sky with nice white clouds. With slide film, you would probably try to meter for the sky and the clouds, so that they didn’t blow out (turn completely white).

By doing this though, the trees would probably turn out to be sort of dark and harder to make out, just because slide film doesn’t have the range to expose scenes with different extremes of brightness. Colour negative film, however, is great at this, and it would be a better choice if you wanted to capture the nice bright sky and clouds, as well as the detail of the darker areas.

This example also highlights a difference between slide film and colour negative film: Shooting slide film is sort of like shooting digital photos: The big danger is overexposing your photos, and winding up with blown-out highlights.

Conversely, when shooting colour negative film, it’s a lot harder to blow out the highlights, even if you overexpose the film a fair bit (here’s a great article talking about this).

And worth noting: Whether you’re using slide or colour negative, underexposure is always bad, and is generally worse on slide film too. Even underexposing slide film by 2/3 of a stop can make the photos muddy.

Okay, I hope that helps! I actually just added a lot of information to what I told the person who messaged me, so don’t worry if you pictured them reading all my messages and glazing over!

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