An Insight Into Polaroid Film By Emrhys Stead
What’s the deal with Polaroid film?
First introduced in 1947, Instant/Polaroid film was a game changer. Before the digital era, we so comfortably live in today, shooting film, waiting to get it developed, and having a photograph printed was the norm. Until one day a scientist by the name of Edwin Herbert Land, struck gold (or more appropriately, silver). Inventing a camera that could both develop and print photographs instantly, right before your eyes. This at the time was revolutionary! Polaroid cameras however aren’t much different to any other; the real magic is in the film.
In order to understand Polaroid film, we first need to understand film in general. While I won’t go too far in-depth on the science behind film emulsion (however possibly a future blog? Let us know) I’ll sum up the just of it. Film consists of a plastic base, coated with particles of a silver compound. When exposed to light, this compound forms silver atoms.
Original black and white film has one layer coated with this compound while colour film has three. In colour film, the top layer is sensitive to blue light, the next to green, and the bottom layer to red. When the film is exposed, the silver compound in each layer reacts to light of that colour creating a photograph.
To turn this chemical recording into an image, the film needs to be developed using various chemicals. The first chemical developer turns the exposed particles into metallic silver. Following that the film is treated with three dye developers, each reacting to one of the colour layers in the film. In regular colour film, the dye attaches to the exposed areas resulting in a negative image. In colour slide film, however, the dye attaches to the unexposed areas. the two dyes that attach to the unexposed area combine to form the actual colour captured on the exposed layer (more on this in a future blog?).
Instant film development combines colours basically in the same way as colour slide film. However, the developer chemicals are already present in the film. Underneath each colour layer in instant film there’s a developer layer containing dye couplers. All of the layers sit on top of a black base layer; and underneath an image layer, timing layer, and acid layer – a chemical reaction waiting to happen. What gets this chemical reaction going is the reagent (a list of elements including acid neutralisers, white pigment, light blockers and others). Before taking an image the reagent material is gathered in a pouch at the border of the film sheet, away from the light-sensitive components. This is to make sure the film doesn’t develop before it’s fully exposed.
After taking a photograph the instant film is passed out of the camera through a pair of rollers. (In another configuration the reagent and developer are coated on a separate sheet that is pressed up against the film sheet for a set amount of time.)
The rollers spread the reagent material out across the sheet of film, allowing for the chemical reaction and development of the film to take place.
Voilà, instant film! That’s a brief look into Polaroid emulsion and the ‘magic’ of instant film. All of this and more goes into every frame of instant film, so next time you snap a Polaroid think of the genius ingenuity that went into creating it.
