By using a pair of polarizing filters and a property of certain materials called birefringence we can photograph the hidden stresses in hard plastics. This instructable was inspired by this article and a comment I read in another instructable, somewhere, about LCD monitors and polarization.

Step 1: What You Will Need

A laptop or LCD monitor. LCD's have a built in polarizing filter, and will act as our light source.

A polarizing filter to mount onto our camera.

A tripod


A selection of hard, transparent plastic objects.

Step 2: Procedure

In a darkened room. Turn on the laptop and create a white screen, I used clipboard on a Thinkpad 380 running win98, or you can create a white image in an editor and view it full screen. Mount the camera on the tripod and point it at the laptop screen, zoom in until the screen fills the camera's field of vision. If you haven't already, fit the polirizing filter onto the camera, slowly rotate the camera filter until the laptop screen goes black (you need to use the lcd on the camera, an optical viewfinder won't turn black ;-)). When the screen appears black from the camera's perspective we've achieved "cross polarization". Now we can start with the pictures.

Step 3: Taking the Pictures

When we insert a hard plastic item into the field between the laptop and the camera, the birefringent property of the plastic causes the light's angle of polarization to change, since our light is no longer "cross polarized" it becomes visible again to the camera. And since different wavelengths have different refractive indices the visible light appears as a rainbow of colors. Exposures are on the order of 1/2 second so a stand should be used to hold the object.

Have Fun.
Brilliant! I want to try it. Might need to scavenge my polarized sun glasses.
Really nice instuctable!... If you have an old calculator LCD you don't even need the camera filter, you can peel the polarizer filter of that LCD an put it on the camera lens
i remember seeing some patterns like that n clear plastic when i was much younger.. guess i know how to have a clear look and know what it is now <br> <br>great instructable..5stars
This looks great :D I got a great affect with cellophane wrapping. I didn't have a polarising filter so i used one of the lens from 3D cinema glasses, and it works great :D
This doesn't work for JUST clear plastics, I remember my first Polaroid sunglasses and the effect of looking through automobile windows, etc. There is whole world of clear stuff to photograph :-)
I remember that too, when I&nbsp;realized &quot;hey those splotches change when I rotate my head... are these windows polarized?&quot;<br /> <br />
&nbsp;This is gorgeous! &nbsp;Thank you for posting it.
I&nbsp;always find it incredible the wit people will employ to capture the true beauty of things.&nbsp; You've found a way to do this that's easy enough for everyone take advantage!&nbsp; <br /> <br /> When did you realize that plastic <em>in between</em> two polarizing filters would achieve this effect?&nbsp; Learned or experimented?&nbsp; Either way, brilliant.&nbsp; Just brilliant.<br />
Too bad you can't take pictures of larger things, well unless you have a giant screen...... would a TV work you think?
if you can get a sheet of polarized plastic, you can set it in front of a light box, and use a second sheet in front of it. Just put the object you wish to view in between. My favorite is a clear disposable cup. You can see the stresses caused by the injection process. Also, try bending the objects and observe the stresses changing. Good for visualizing stress points in parts .<br />
I see things like that through my sun glasses! It's really cool.<br />
Ok,&nbsp; here are my first <em>real</em> attempts,&nbsp; not so good, but better than my others that had an extra filter on it ;-)&nbsp; The first one became blurry because I&nbsp;bumped the tripod....<br /> <div id="refHTML">&nbsp;</div>
Something that is hard to see in these since they've been downsized, on the second one it is more apparent however, although the stresses did not show up as colors in the upper portion of the bottle, it did show up as concentric (but not uniform) circular lines.&nbsp;&nbsp; <div id="refHTML">&nbsp;</div> <div id="refHTML">&nbsp;</div>
I&nbsp;purchased a pair of small &quot;polarized'' filters and used a bottle cap (plastic) and a large plastic washer of sorts, to create my own little camera filter, that can be adjusted. <br /><br />I&nbsp;am sure I&nbsp;followed all the directions above fairly closely, but the pictures below are all I&nbsp;am getting. &nbsp; Is this, by chance, because the filters are not only polarized, but also tinted?&nbsp;<br /><div id="refHTML">&nbsp;</div><br />BTW:&nbsp; the only thing that is really visible is the edge of my home made filter except in the first photo, where a faint outline of the top of a plastic water bottle can be barely made out). <br />
<input type="hidden" id="gwProxy"><!--Session data--></input> <strong>Any suggestions?</strong>&nbsp;<input type="hidden" id="jsProxy" onclick="jsCall();" /><div id="refHTML">&nbsp;</div>
Sorry,are you saying both the filters are in the bottle cap??<br />
The <strong>cap</strong> is a water bottle cap, and there is a space of about 3/4 of an inch between the filters,&nbsp; one is on a plastic ring that I&nbsp;have snapped onto the end of the cap, and the other filter is on the other <em>end</em> of the cap. <br />
Oh, there's your problem, the item to be imaged has to be between the filters. Another consideration is some polarized filters only work in one direction because some contain a 1/4 wave retarder (it let's them work with digital cameras).<br />
You mean you polarized filters are not mounted on the camera?&nbsp;<br />
One is, the other is the polarized screen on the laptop<br /><br /><br />
<input type="hidden" id="gwProxy"><!--Session data--></input>OH,&nbsp; bloody&nbsp; h&nbsp; 3 double match sticks...... Here I made the filter out of two polarized lenses......no wonder it didn't work......I will have to find some time to see if&nbsp; I can correct that and try again......thanks for getting my <em>head on straight</em> again :-)&nbsp;<input type="hidden" id="jsProxy" onclick="jsCall();" /><div id="refHTML">&nbsp;</div>
Lovely stuff. I haven't thought about doing this since high school physics class when we were analyzing stresses, but I recall being fascinated by the aesthetics to the point of forgetting to record the results. Thank God I went into art and not engineering. If anyone has seen a 3-d movie lately, several seem to be using polarized (one eye vertical, one eye horizontal) glasses which can be fun for this sort of stuff if you pop out the lenses.
&nbsp;That's how I found this out - I tried watching TV through 3D movie glasses and found that one eye blocked out the screen
Only the serious movies / cinemas use polarization instead of the red/blue 3d effect. I haven't seen it anywhere other than iMax cinemas. I think it's because it's so much more expensive to produce than the red/blue 3d. If anyone has seen it in lotsa other places, go ahead and prove me wrong.
I havent seen it in lots of other places, but i was just at the Franklin Institute in Philly, and and thier imax theater uses the polarizing type.
I got mine at Up at our normal town theatre. It's a pretty big theatre, though.
They use polarized glasses on the 4D adventure at Noah's Ark waterpark in the Wisconsin Dells. It's amazing how much better it is than the simple red/blue glasses - it really aids in making the effects realistic.
I got mine at Nightmare before Christmas 3-D last fall. Not at the IMAX.
lol i typed IMAX like iPod... force of habit I see. well it may be different in USA, but here in gayass Australia (in my experience) they're not common. BTW I know ur American 'cos u said 'fall' instead of autumn like the rest of the planet
The rest of the <em>planet?'&quot; Let's not forget the english speaking population is only part of the world. (Just had to say that...)</em><br/>
Heh, this is too much fun. I spent the better part of an afternoon experimenting. I found that glucose syrup in the bottom of that volumetric flask changes through a variety of colours depending on polarization axis.
I thought that this was very cool, and tried it out on my own. Here are a few pictures (taken with phone, camera battery was dead). i couldn't fit a filter to the phone, so i just held up a pair of polarized ray bans in front of the camera. i experimented with the white background, and decided that i could make just the polarization appear if it was white behind the plastic, and it wouldn't appear if it was behind a black background, and of course felt obliged to write "instructables" on it. the second used the negative effect of the camera, and the third is showing how the sunglasses filter the light
man,i think that's awsome.very cool dude
That is so cool!!! :-) Would it also work on glass?
Does this work with DSLR cameras? I have to use the viewfinder :/
On a DSLR, the viewfinder sees through the lens, so it will work. the reason the viewfinder doesn't work on a point and shoot is that it doesn't see through the lens, but through a small hole above it, bypassing the polarizing filter.
how do i know that the lcd screen turned black? The guide said it was only possible if viewed through the lcd of the camera
you have to rotate the polarizer ! (circular)
shure it works with DSLR, I used my 20D to make those:<br/><br/><a rel="nofollow" href="http://www.flickr.com/photos/8938408@N05/553797611/">http://www.flickr.com/photos/8938408@N05/553797611/</a><br/><a rel="nofollow" href="http://www.flickr.com/photos/8938408@N05/553797499/">http://www.flickr.com/photos/8938408@N05/553797499/</a><br/><a rel="nofollow" href="http://www.flickr.com/photos/8938408@N05/553797461/">http://www.flickr.com/photos/8938408@N05/553797461/</a><br/>
thats really cool
can i buy plastic forks on ebay? the clear kind. what size?
Try the local supermarket, picnic supplies.
but i only need one.
Steal one out of the box. No one cares for one fork. Just don't let them see you.
buy a take away then
Forkin' hell, that fork looks sublime. Nice instructable, I have witnessed this when wearing my fully polarised (they are designed for fishing, so one can see through the top reflection) sunglasses. An alternative method is to get a polariser sun-reflecting sheet for window glass, (yes you can buy it somewhere) and make up a "daylight" (fake but close to) light box, IF you wanted to do lots of photo's of just such a thing. I recall being on a coach and saw that the smooth curved glass at the top of the bus (on the roof edge angle) was displaying the stresses it was under, due to a polarising layer on the outside of the glass. I should have liked to see a bit of glass like that break, watching the stresses change in slowmo. I have a polariser for my all of my D-SLR's as well, i'll have a bash at some photographs.

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