Have you ever looked back at the days when you were starting out with photography and everything was fun and thrilling and interesting? Have you ever wondered where all that excitement has gone?
Whether you are stuck in a photographic rut or simply looking for some creative photographic ideas, photoelasticity is an easy and fun project you can do. You’ll come up with great artsy pictures, some fresh ideas and give your creativity a boost.
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What is Photoelasticity
Photoelasticity determines the stress distribution of material through experiments. It’s mostly used when mathematical methods become too difficult to put into practice. And so on.
At this point I can almost see the puzzled expression on your face, but remember this. Photography is as close to science as it is to art.
In fact, the study of what happens to light (not necessarily visible light) is one of the most valuable scientific tools. It’s used to investigate everything from the composition of distant stars to the characteristics of everyday materials.
Photoelasticity is interesting because the stress stored inside a material can become a colourful fringe pattern under the right circumstances.
Photoelasticity for a ripped film of clear plastic shows that the unstressed part of the film appears homogeneous in colour. Near the rip, however, a rainbow of colours appears.
This is where all the stress went when I stretched the film past its breaking point.
How to Use Photoelasticity at Home
To play with the artistic side of photoelasticity, you don’t need any fancy equipment.
All you need are some objects made of semitransparent or clear plastic, a polariser filter and a light source able to emit polarised light.
Unfortunately, common light sources such as the sun, bulbs, LEDs and flashguns do not emit polarized light.
If you are wondering what light source you should use, you are looking at it right now. The LCD screen of your computer, your tablet or your cellphone, all emit light polarised in one plane.
You can easily verify this by looking at your screen through a polariser. You can then observe how it turns darker and then solid black as you rotate the polariser more and more.
By rotating the polarizer you are selecting different polarization planes. This blocks more and more the amount of screen light passing through the filter.
When you rotate the polarizer 90 degrees, you have effectively suppressed all the screen light.
How to Set Up for Photoelasticity
The images below show the effect of a simple plastic wrap placed on my iPad screen (perfect size for small objects), with and without polariser.
To photograph the colourful fringe patterns of larger objects I prefer to use my laptop. I can have the monitor flat on a table and arrange objects directly on top of it or I can place it vertically.
Like that, it lights the objects from farther behind (like in the image below).
Cameras and Camera Settings for Photoelasticity
For this project any camera will work, including compact cameras and camera phones. If you cannot mount a filter, just hold the polariser in front of your lens and you will be fine.
Or you can buy a filter adapter. The Phot-R 37mm Filter Clip allows you to use 37mm filters with a cameraphone such as the iPhone.
ExpertPhotography recommends: Phot-R 37mm Filter Clip.
I prefer to work in manual, in order to have consistent exposure throughout the photo session. All the photos presented here were taken with my Sony RX100 Mk2 compact camera.
I tend to manually focus the scene. If the objects are displayed directly on to the monitor, I try to shoot with the widest aperture possible. That way, I’ll have minimum depth of field and I’ll be able to blur the screen pixels as much as I can.
The only thing that remains to do is to visualise a white image full screen and to crank up the screen brightness.
ExpertPhotography recommends: Sony RX100 Mk2
What To Photograph
I have already said you should photograph objects made of transparent plastic, but plastic is a very generic term. To be honest, I cannot tell you exactly which kinds of plastic will work and which ones will not.
You should go grab every object you can find that is made of semitransparent or clear plastic and try for yourself.
This is where most of the fun comes from, and this kind of treasure hunt can get you addicted. The next time you’re at the grocery store, you might end up buying more plastic than food.
Let’s see some results in detail.
One of the first things I tested was a plastic water bottle and I got almost no fringe pattern.
Plastic bottles for the food industry are made of PET (polyethylenetereftalate), which is a type of amorphous plastic material.
I suspect the degree of crystallinity and/or the fabrication process of the material do play a role. Some other PET containers show stronger fringe patterns, but I am not an expert on this.
What I know is that this kind of bottle does not work well for this project.
Many rigid plastic containers, such as photographic filter cases and CD and DVD cases work very well. If you look carefully at them in the light of your computer screen, you might even see a faint fringe pattern with the naked eye.
Those objects are usually made of polypropylene (PP). This is a much more dense and crystalline plastic than PET.
Sometimes you can know what kind of plastic an object is made of from the recycle symbol. Unfortunately, not all plastic objects have an impressed recycle symbol.
Plastic Cutlery, Glasses and Straws
Clear plastic cutlery, glasses and straws you usually use for parties or picnics look stunning.
Plastic Bags, Food Packaging and Other Food Containers
Do not limit yourself to experimenting only with objects made of hard plastic. Plastic bags used to freeze food or for food packaging can give amazing results creating compelling abstract images.
Small food containers usually have lots of stress in them and should display a great, symmetric, fringe pattern.
Low Key or High Key?
You may have noticed that, until now, I have shown you only images in low key style. You don’t have to suppress the light of the screen with your polariser for photoelasticity to work.
I like the low key style more, but high key images are great as well.
Anything Could Work for Photoelasticity
Once again, this project is all about fun and you should not be take it too seriously. Look around you and don’t be afraid to experiment and test wild ideas. Worst case, you lose a few seconds of your life trying something that did not work.
When things work, though, the reward can be huge. I had this Lego model of the ISS (International Space Station) hanging around at work.
It has a great array of solar panels that are made of clear plastic. Needless to say, I promptly tested it.
Getting Creative With Photoelasticity
As I said, photoelasticity is so easy and fun to do that you will soon begin asking yourself: “Now what? I want more!”
Once you have experimented with different objects and saw how they respond to photoelasticity, it is time to get more creative.
You can combine different objects together, while also playing with the composition and message of your photos.
The previous photo of the ISS is great because it looks like it really is in space. I could have stop there, but I am into astrophotography as well.
I decided to do a composite image using a shot I took of the moon, the ISS and the space shuttle approaching it.
Go With The Flow and Be Creative
Water has a refractive index quite different from that of air. If you partially submerge something in it, like a stick, the stick will look broken.
The part of the stick outside the glass, and that submerged in water will appear to be in different positions.
Here I did the same, just using a straw instead of a stick. Air bubbles were a welcome accident.
Usually, the creative process is a continuous flow of ideas, each one based on what you did before. Wouldn’t it be nice to have two glasses forming a heart with their straws? Yes, it would!
The next results were so unexpected that they looked like magic to me. A spherical food container turned into a magic ball floating in the hand of a wizard.
Two Artistic Practical Uses For Photoelasticity
All these images are nice and can wake up your photographic enthusiasm and creativity. They will also get you quite a bit of likes on social media. But their usefulness ends there.
Or does it?
Before concluding this post I want to give you a couple of examples for when this kind of work has practical use.
If you are good at drawings (which I am not, unfortunately), you can craft your art for yourself. You could get something different by creating a mask of your drawing to put in front of plastic wrap.
This will show strong, colorful fringe patterns.
Finally, if you are a graphic artist, you can put photoelasticity to good use. It provides you with the tools to easily create colourful abstractions you can use to fill in a text.
I hope this post has ignited your curiosity and that you will give photoelasticity a try.
Just remember: don’t overthink it and never stop having fun and experimenting with materials and ideas.
Looking for more fun photography activities to do with children?
If you’re getting colourful effects you didn’t plan for, perhaps you should take a look at our guide to Chromatic Aberration and how to deal with it? We have a great article on creating cool glitch art photos too!