The Noir Files

I mentioned in a previous post that as far as I could remember, I had never shot a black and white (B&W) photograph. No point in losing all that rich hue information, I reckoned. The other day I was hiking around a forested area when I decided to change the setting on my Olympus TG6 camera and put it on monochrome, which is to say black and white (or grayscale). I pointed it at some foliage and immediately regretted it. It was all a mass of black and white shrubbery. Gone were the rich greens and woody browns. I believe I deleted the image. So, I changed the camera setting back to colour and continued my hike. The results of this hike are my entry for this #monomad challenge.

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Monochromatic setting in camera

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Vivid colour setting in camera

I have a bit of a stubborn streak and kept mulling over why my first photograph did not turn out so well. Later, I found a fern and kneeling beside it, I took a close-up shot in B&W. I was immediately thrilled by the look of it. That was the trick! I remember thinking. Devoid of colour information, a monochromatic image had to use what remained: light contrasts, recognizable shapes, textures, and structures that convey the nature of the scene.

I continued photographing in monochrome and at some point, I decided to compare the results versus colour photographs. So for each scene shown, I took two photographs. One in monochrome, and the other using the Vivid colour setting in the camera. This is why you might see slight changes in composition between the two images. I did not carry out any post-processing of the raw files, which I then exported as JPG.

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All of this took me back to my student years when I was learning about the visual system. So, I dusted off some old books and cranked up the Internet tubes to do some more learning. I was particular interested in the differences in how humans process visual information in colour vs grayscale. I found some really interesting geeky facts about it, and I thought I would share them with the Black and White community.

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The visual system is an exquisite machine that besides the eyes involves multiple brain areas when processing environmental elements like objects, luminance, and colours. Scientists don’t fully understand how we process them but thanks to a combination of theories and scientific work, they have a good guess about how it all operates (at least on a general level).

The complicated thing is that a perceived colour is not just pure information but rather it is a combination of signals that have been filtered in multiple ways. The colours that we actually see in the world around us are basically the Instagram version of reality, filtered through multiple processing layers along the way.

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It turns out that the brain processes colour and grayscale information in different but often complimentary ways. Early on in the process, chromatic and achromatic signals share retinal mechanisms. A photon of a particular wavelength- short, medium, long- strikes the retina. Different wavelengths carry different types of information that when mixed correspond to red, green, blue, or grayscale. The human retina is able to exquisitely capture this and other information using photoreceptors.

The photoreceptors that make up the retina are called rods and cones. The rods are sensitive to luminance and achromatic vision (black and white). The cones are sensitive to acuity and colour information (as determined by the nature of the wavelength that strikes them). So, when we see a colour photograph, then the cones and corresponding brain mechanisms become active. But when viewing a black-and-white photograph, the rods get excited and pass on the luminance/achromatic information for further neural processing.

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This is where things start getting even more complicated because the two systems for colour and grayscale information diverge. Colour information is transmitted to the Lateral Geniculate Nucleus in the thalamus via the parvocellular nerve pathway, while luminance (grayscale) information is sent along the magnocellular pathway. At this point, attentional mechanisms come into play and affect the final render of the image that we see and experience. The information is relayed to other visual areas of the brain where the signal undergoes further elaboration, refinement, and processing. It’s basically as if our brain edits the raw image information with Photoshop using a lot of in-app and homemade filters.

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At higher levels of visual processing, colour and luminance information once again come together to share mechanisms that determine the final impression of colour, object, shape, texture, etc. Context information from other areas of the brain are also important for colour determination at this stage, and the brain mixes that information as well.

As you can see, most of the images that I took contain natural objects like trees, which we would expect to be green. The ocean, sky, and distant mountains would be expected to be blue. Although the colour information is missing from a B&W image, the extra context could cause the brain to fill in information by activating colour cells without actual external light input. The brain just makes it up based on expectations and even emotions, which is kind of spooky when you think about it.

I could go on. Trust me, there’s much more where that came from. The visual system is crazy. The point being that colour and B&W photographs are processed somewhat differently in the brain. Interestingly, people who have suffered damage to their colour perceiving abilities after a stroke did not lose their ability to detect luminance and shape recognition. It turns out that grayscale information is sufficient to recognize objects on a scene, and it is processed by a different physical mechanism than that of colour information.

During my photographic exploration, I began to focus on areas where light-shadow contrasts were clear. I found myself paying more careful attention to composition, even the mood of a photograph. Since then I have taken more shots in Black and White, and I will share them next time.

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