OK....here is what a scene, any scene, would more or less look like to us as observers in 'infrared' if we eliminated the visible light wavelengths.
Infrared Scene
The point I am trying to make is that when most people talk about infrared photography they are often under the mistaken impression that it represents what we would see if we (humans) could see the infrared portion of the electromagnetic spectrum. But, of course, we can't. So if we were relying on the infrared portion of the spectrum to see....well, we wouldn't see very much.
So what are we seeing when we look at infrared photographs? Well, we are looking at how the infrared film or the digital sensor reacts to the infrared portion of the spectrum. It is how the film or sensor 'sees' infrared because infrared can be detected by them. That is to say, both are sensitive to the infrared portion of the electromagnetic spectrum. Our eyes are not.
So when we look at an infrared photograph we are seeing the portion of the visible spectrum that the film or sensor has converted the infrared into. What we see is, by necessity, an interpretation. So what does infrared 'look like' to the several insects, snakes, and ferrets that can see this portion of the spectrum? Perhaps it gets philosophical, but I don't know and I'm not sure anyone truly can. These insects and animals were born with eyes that are sensitive to infrared so they probably don't think it is anything special! Perhaps it is like trying to explain to someone that has been blind from birth what 'yellow' is.
That said, here is an infrared digital image of Cucumber Falls at Ohiopyle State Park in Pennsylvania. At least this is how the digital sensor (with visible light filtered out) converts the scene to something that we can see.
Cucumber Falls In IR
Copyright Howard Grill
6 comments:
Of course, the same is true for the 'visible' portion of the spectrum.
Hi Tom...I assume you are referring to the fact that even with 'routine' visible light photography the image ends up representing the sensors interpretation of the light! Fair enough. Add to that the fact that when we process the RAW image, if shooting RAW, we then add our own interpretation. Then we start to get into the whole is photography truth issue....and of course it isn't, there is always interpretation (http://www.outbackphoto.com/open_your_eyes/oyi_004/essay.html).
Hi Howard,
Yep, you catched my drift.
Photons (whatever they may be) reflected by a subject travel pass through thick pieces of glass, where they are diffracted and filtered. Then they go through a low pass filter in front of the sensor. Then some go through a red, green or blue filter. They then generate a charge. This charge is converted into a digital value by electronics. Those values are combined again to produce colors other than red, green or blue. An analogue, but different story could be told for film. Or about the way photons travel through an eye and are detected by the retina and generate signals in the brain.
Or how those numbers are used to convert them back to something visible again, either on a monitor or printer.
Well, what I'm trying to say that in the end we're trying to produce something that's either close to what we think we saw or what we felt, or something that we just like. So yes, it's all interpretation, there's no recording of what we see.
Thanks for the link. Interesting reading material !
Cheers, Tom
Thanks for some great comments and thoughts Tom. In addition, even if I could get on paper or monitor exactly what I saw, that may not be exactly what you would have seen had you been there, as we all 'see' colors a bit differently as well!
Probably, no two people experience the same stimulus exactly alike....which, I believe, is a good thing!
I agree, we all see colors differently (very true for the color-blind). Colors are just some agreements mankind made. We can't really tell how each individual experiences them.
And you could also throw into the equation the fact that we don't see the whole picture with our eyes, but we constantly scan tiny parts and we kind of generate an illusion of a whole picture in our brains. Or the fact that we can't see color-casts (or light temperature), because our brains filters those away and we can't switch this filter off. But cameras (or sensors), they 'see' them, so we have to adjust for them in the numbers that the camera generates.
Thank you for some great blogging !
Cheers, Tom
And thanks for some very insightful comments!
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