How do instant cameras work?

explore how we make decisions. Are people with high i Qes? The best decision makers? Not necessarily are hastily made decisions the best find out the fascinating science and psychology behind the human decision making process in Blink by Malcolm Gladwell, available from Audible. To try Audible free today and to get a free audiobook of your choice, go to Audible podcast dot com slash brain Stuff. That's Audible podcast dot com. Slash brain Stuff. Him Marshall Brain with today's question, do

you remember the Polaroid camera with the instant film? How did that film? Wark? How could you take a picture and have the picture developed right in your hand in just a minute or two instant camera film is remarkable because it has its own built in developing studio. To understand how this works, you need to understand the basics of traditional photographic film. This has mostly been replaced by digital cameras today, but it's still interesting and it's a

great chemistry experiment. Film is a plastic base coated with particles of silver compound that are sensitive to light. Black and white film has one layer of silver compound, while color film has three layers. The top layer is sensitive to blue light, the next layer is sensitive to green, and the bottom layer is sensitive to red. When you expose the film, the sensitive grains of each layer react to light of that color, forming metallic silver at that layer.

This gives you a chemical record of the light and color pattern. To turn this into a picture, you have to develop the film. One developer chemical turns the exposed particles into metallic silver. The film is then treated with three different die developers containing die couplers. The three die colors are cyan, a combination of green and blue light, Magenta a combination of red and blue light, and yellow,

a combination of green and red light. Each of these die coupler types react with one of the color layers in the film. In ordinary print film, the die couplers attached to particles that have been exposed. In color slide film, the die couplers attached to non exposed areas. Developed color film has a negative image, the colors appear opposite of the colors in the original scene. In slide film, the two dyes that attached to the unexposed area combined to

form the color captured at the exposed area. For example, if the green layer is exposed, yellow and cyande will attach to either side of the green layer, but the magenta dye will not attach At the green layer, the yellow and cyan combined to form green. The instant camera developing process combines colors the same basic way that slide film does. It has the same layers of light sensitive grains as traditional film, all arranged on a plastic sheet.

The film also contains several additional layers. However, these layers contain all the necessary chemicals for the development process. Underneath each color layer, there's a developer layer containing die couplers. All these layers sit on top of a black base layer, and they sit underneath the image layer, timing layer, and acid layer. This arrangement is essentially a chemical chain reaction

waiting to be set into motion. The component that gets the developing process going is the reagent, as in reagent, a mix of a pacifier's alkali white pigment and other elements. The reagent sits in a layer just above the light sensitive layers and just below the image layer. Before you take the picture, the reagent material is all collected in a blob at the border of the plastic sheet, away from the light sensitive material. This keeps the film from

developing before it's been exposed. After you snap the picture, the film sheet passes out of the camera through a pair of tight rollers. The rollers spread the reagent material out into the middle of the film sheet, just like a rolling pin spreading out dough. When the reagent is spread in between the image layer and the light sensitive layers, it reacts with the other chemical layers in the film. The obasifier material stops light from filtering into the layers below,

so the film isn't fully exposed before it's developed. The re agent chemicals moved downward through the layers, changing the exposed particles in each layer into metallic silver. The chemicals then dissolved the developer die, so it begins to diffuse up toward the image layer. The metallic silver areas at each layer. The grains that were exposed to light grab the dies, so they stopped moving up. Only the dyes from the unexposed layers will move up to the image layer.

For example, if the green layer was exposed, no being jet to die will make it to the image layer, but cyane and yellow will. These colors combined to create a translucent green film on the image surface. Light reflecting off the white pigment and the reagent shines through these color layers the same way that light from a bulb shines through a slide. There is one problem left to solve. Recall that there was this opacifier that made it so

that light couldn't get in to expose the film. While all this developing is taking place, how do you make the image clear? It turns out that at the same time these re agent chemicals are working down through the light sensitive layers, other re agent chemicals are working up through the upper film layers. The acid layer in the film reacts with the alkali and opacifiers in the reagent, making the opacifiers become clear. This lets you see the

image below. The timing layer slows the re agent down on its path to the acid layer to give the film time to develop before it's exposed the light, and you can see it. When you watch the image in a photo film come into view, you're actually seeing this final chemical reaction. The image is already developed underneath. You're just watching the acid layer clear up the opacifiers in

the reagent so the image becomes visible to you. This podcast is brought to you by audible dot Com, the Internet's leading provider of audiobooks, with more than one hundred thousand downloadable titles across all types of literature and featuring audio versions of many New York Times bestsellers. To try Audible free today, and to get a free audiobook of your choice, go to audible podcast dot com slash brain Stuff. Be sure to check out our new video podcast, Stuff

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