Instant Photos Explained: The Science of Polaroid Film

Posted on February 17, 2024 by admin

How Polaroid Film Works

A brief overview of the instant photography technology

Polaroid film is a type of photographic film that produces instant prints without the need for a darkroom or a chemical process. It was invented by Edwin Land in 1947 and became popular for its convenience and novelty. Polaroid film consists of several layers of light-sensitive materials, chemicals, and a plastic cover. When the film is exposed to light, a chemical reaction occurs that creates a latent image on the film. The film is then ejected from the camera and passes through a pair of rollers that squeeze a pod of developer solution onto the film. The developer solution spreads over the film and initiates a second chemical reaction that reveals the image on the film. The image is fully developed in a few minutes and protected by the plastic cover. The process of polaroid film is different from conventional film, which requires a negative and a positive print to be made separately.

In 2008, Polaroid discontinued production of instant photography print film. The last facility was purchased by a private party. Since the chemicals used in the process below were no longer legal to produce and use in a product, the new company, The Impossible Project, had to recreate from new in order to create and sell the famous film. Each batch has slight tweaks and improvements as well challenges to the quality and success of the prints. Purchasers of the film should know it is a complicated mix of chemicals that at times, especially in hot and cold environments, may provide creative results.

How the Polaroid Film Layers Work

The top layer of the polaroid film is the plastic cover, which protects the film from dust, scratches, and fingerprints. It also acts as a filter that blocks ultraviolet light and enhances the colors of the image.
The next layer is the image-receiving layer, which is a transparent sheet that contains dye molecules that react with the developer solution. The dye molecules are initially colorless, but they change color when they combine with the developer solution. The image-receiving layer forms the positive print of the image.
The third layer is the image-forming layer, which is a sheet of silver halide crystals that are sensitive to light. When the film is exposed to light, the crystals form a latent image that corresponds to the brightness and contrast of the scene. The image-forming layer forms the negative of the image.
The fourth layer is the timing layer, which is a thin layer of gelatin that controls the rate of the chemical reactions. The timing layer slows down the developer solution so that it reaches the image-receiving layer at the right time. The timing layer also prevents the developer solution from reaching the image-forming layer, which would ruin the image.
The fifth layer is the acid layer, which is a layer of acidic material that neutralizes the developer solution after it has reacted with the dye molecules. The acid layer stops the development process and stabilizes the image.
The sixth layer is the opacifying layer, which is a layer of black pigment that blocks the light from reaching the image-forming layer. The opacifying layer prevents the image from fading or changing color over time.
The bottom layer is the base layer, which is a plastic sheet that supports the film and provides rigidity. The base layer also contains a pod of developer solution that is ruptured by the rollers when the film is ejected from the camera.

Making the Connection SX70 to Neck Strap

Posted on November 27, 2016 by admin

If you have a SX70 neck strap (rather than using a generic camera neck strap), you may have noticed that the end of the clip has a curve to it. The factory design clip is a squeeze type that isn’t a straight clasp.

Original Polaroid leather neck strap with clasps

You can clip onto the camera with the clasp curve either way. If you think about it, you could reason that one way might force the camera away from the body, while the other way may allow the camera to hang straight. Is there actually a ‘correct’ way?

Yes, Polaroid does specifically call out on their packaging one way is correct, the other isn’t.

Polaroid Guide for SX70 Neck Strap Attachment

Holding the camera by the bottom, the clap connects from the bottom up, rather than clipping downward. The science behind that? I have yet to find that, but will let you know when I do.

Polaroid 600 Focus – If You Can Touch It, Your Too Close

Posted on November 21, 2015 by admin

The Polaroid camera says to the photographer, “It’s not me, it is you”.

This article is about being successful at taking instant print photos with a Polaroid 600 OneStep that are in focus. This is the same for all auto eject cartridge Polaroids with the exception of Sonar focus SX70 and 660, manual focus models SX70 and Pronto RF and the SLR680/690 models.

Polaroid put all of the technology in the 600 models around the flash. The flash is electronically controlled based on the light in the area and the light from the flash bouncing back to the camera sensor. Polaroids will automatically adjust the strength and length of the flash.

For focusing, the 600 is built to take photos of things just over 4 feet away to infinity, thus is called a “Fixed Focus”. I get a lot of folks dropping by with cameras they have bought online, at yard sales, from the manufacture and rebuilders. They ask me to adjust the focusing of the camera as they are getting prints that are out of focus. There must be something wrong with the focusing!

First, there has to be an appreciation of how a 600 model produces a print. There is a plastic lens that can be seen on the front of the camera. Behind the lens is a shutter arm that allows light (the image) to enter the camera. The light is reflected off of a mirror and down onto the print film. That is it. There is no moving parts for the focusing… other than the photographer. So, it is important to know the limitations of the camera and adjust to live within those. As the title of this article says, if you can touch the object your taking a photo of, your too close.

How far is ‘further than 4 feet away’ Try standing with your toes against a wall. Leave one foot against the wall and place the other foot toes to the heal of the foot against the wall. Take the foot that is against the wall and put it’s toes behind the foot that is behind… basically your going to back up toe to heal, five times. As long as you have average size adult feet, the distance you are away from the wall after doing the toe to heal 5 times is how far away from something to have it be in focus on the print. You have to actually be more than 4 feet away, since with the camera in front of your face it will be another 6 inches plus closer to the object being photographed.

“This wasn’t a limitation in the old days”. I had a manual focus SX70 and a early 600 in those ‘old days’. As well, I buy a lot of Polaroid prints from estate sales as reference. When film was all there was, people had learned the limits of their film cameras and adjusted their expectations. We are all so used to digital photography and near limitless software tuning our images, it is easy to forget the things we did without thinking about it because that is what we had to do.

Almost all of the latest 600 OneStep Polaroids do have a slide over ‘Close Up’ lens. Don’t forget you have that for those times you find you need to take a picture of things closer than 4 feet. I find the solution works nicely for things 3 feet to just over 4 feet away, even though most literature claims you can get as close as 2 feet from your subject.

One last item to consider when needing to photograph a item in low light that appears to be ‘out of focus’ in the print, it may actually be that those parts are over exposed. If your in a very low light area, the camera sees that and adjusts the flash to fill as much as it can. If you have a single individual’s face around 5 to 6 feet away, the flash may wash their face out due to the light attempting to fill in the dark areas. You are then getting a heavy light reflection off the face. You may try having the person turn there head slightly or add more light to the area so the Polaroid doesn’t do a maximum flash.

I am challenged with where the point is that is just over 4 feet away. So, I purchased a small laser range finder for around $45 US. There are many options on the market. Or, a small tape measure is less tech but can be really small to carry.

SX70 Sonar Getting More Using A Flash

Posted on October 31, 2015 by admin

The obvious beauty with using a SX70 Sonar is it is simple to use. You can actually focus on things near or far away for nice depth photos. The autofocus is fast and you can see through the viewfinder what you will get. Not general information like with the 660 Sonar Autofocus or 600 Autofocus, cameras that have a viewfinder separate from the photography lens’s view.

The less obvious, but equal effect for tuning photos is using a flash. I use a Mint Electronic Flash (available direct or through The Impossible Project) when using a older Polaroid Box camera or the SX70 (Alpha and Sonar). The Mint Flash has a 1/2 power and full power setting. Most people use the default of Full Power for SX70 film and 1/2 Power for 600 film. Included with the flash is a couple color gel defusers.

When looking through the viewfinder, there is a small red light on the right that will appear if the camera feels there isn’t enough light without a flash. It is important to know, you can still take a photo. The camera will extend the length of time the shutter is open. If your going to do a lot of low light photography (like night light tracking), mount the SX70 Sonar on a tripod. If your Sonar doesn’t have a tripod mount screw, there are clip on plates available.

This is an example of a pumpkin with a light inside, in a dark area of the house, white background. I didn’t use a tripod on purpose to show that you can get a reasonable shot but the camera has to be really still. Otherwise you get what looks like light it bleeding but really it is the camera catching the movement with the shutter open.

Next, this is 1/2 Power Flash on the Mint Electronic Flash. Normally the setting for 600 Style film (Impossible Project). As you can see, there is a different effect with the contrast/saturation coming through. Something to consider when looking for impact in a lower light subject. Notice though that the outer edges of the print area isn’t able to get the full power of the light.

Finally, the flash on Full Power, as is suggested by Mint. This results in the classic Polaroid Print we are all familiar with. There is more possible for adding punch to your Polaroid Prints by understanding the power in your hands. And this, without even touching the manual light/dark override dial.

600 Film Use Tips from Polaroid Film Boxes

Posted on May 25, 2015 by admin

On the back of some Polaroid 600 Film boxes where a few tips. Notice that they include distance numbers for the different cameras. Your results may vary when using newer Impossible Project film, but these are a nice starting point.

Getting Close Up shots ‘in focus’

Posted on February 1, 2015 by admin

There was an option on the Polaroid 600 model that doesn’t have autofocus to have a ‘Close Up’ lens built in. This feature was on the Sun/Spirit as well the OneStep 600 (not the box style Polaroids). You will recognize the cameras by the small plastic slider below and to the side of the main lens, between the lens and bright/dark compensation slider.

Moving the lever towards the lens slides a plastic lens over the front of the main lens as well inside of the viewfinder area. These are not precision ground glass lenses, so the lens and distance between the main lens and the close up lens can vary a bit between cameras.

Since this is a lens over a lens, you aren’t taking a camera that focuses 4 feet to infinity and giving it 2 feet to 4 feet range. There is a sweet spot, or distance, that each camera has. Normally, as I move from one 600 OneStep to the next, I find it difficult to get the exact ‘in focus’ distance when using the close up lens. So, I end up with things at different distances in and out of focus.

Using that ‘issue’ to your advantage, there is a first test you should do when you pick up a Polaroid with a close up lens before going out and using the camera. Place the camera in a spot on a long table or on the floor. Now, take small objects (chess pieces, small stuff animals, dominos… etc…) and place on at foot distances away from the camera. Be sure one does not completely hide the one behind it. If you are using things like chess pieces or dominos, you can place one every half foot to get more precision. Now, snap a photo. The print will show you quickly what the perfect ‘in focus’ distance is for that camera.

Holding the camera when pulling the picture out

Posted on November 30, 2013 by admin

Pulling the photo out of a Polaroid, normally I’m paying attention to not tearing the image tab and pulling at a steady rate. But, the hand holding the camera is very important too, and often not done correctly.

In an attempt to make the cameras smaller, Polaroid tightened the space that the film needs to make a 180 degree turn on it’s way out of the camera. Remember, the exposed film is at the front of the camera and must go around the end of the camera to exit at the back of the pack of film. If the camera is held tightly on the end the film is making the sharp turn, it get’s pinched and unable to make the desired trip.

Here you can see the early Polaroid sandwiched between a Reporter and a Super Shooter.

The early cameras had a handle area on one end, where the film is making the turn. The bodies are more solid and the handle is outside of the area of the turn.

The Super Shooter and Big Swinger (not pictured here) have a handle that isn’t just for carrying the Polaroid. The ‘T’ handle is best used to hold the camera firmly when pulling the film out, removing the possibility of pinching the case.

The ‘Reporter’ has a little ring that clicks into the back cover. Most people think this is for locking down the heat sleeve or holding the Pro’s timer. Actually, it flips out and should be used to hold the camera like the ‘T’ handle. But, the ring means fewer fingers holding the camera on pull, a trade off for removing the need for a big strap off the end of the camera.

It is easy to see here how the flip out handle puts the holding area right where the extra area of the camera used to be in the earlier cameras. That extra area was also the battery holder so it isn’t there just as a handle.

The instructions on the back of some Polaroids covers the rest of the process:

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