In low light we see only black and white.

Rainbows are spectral colors, magenta is not spectral, it is a mixture of primary colors.

 

Got the book and it is superb, especially for the issues we are discussing here.

 

The book is full of stuff like this and fits nicely with my previous studies and lectures on seeing. I'm looking forward to more depth. I'm trying to figure out what I need to contribute here from the book. How about this nugget, paraphrased: light passes through the retina, 3 layers of cells, first though ganglion, then bi-polar, then rods/cones. Behind that is a dark pigment layers that absorbs any electromagnetic energy not absorbed by the retina that includes UV so it acts like sunglasses for UV.

Pretty cool.

 

This is definitely worth a read and lays some foundations for this discussion.

 

According to Margaret Livingstone, Ph.D., Takeda Professor of Neurobiology at Harvard in her book The Biology of Seeing:
The rods are responsible for the most acute vision and luminous relativity without color, which is processed by the brain for such things as spatial orientation, object recognition, motion and essential mapping. Cones, spaced further apart, are not as acute but provide color through 3 types of cones. Think in terms of detailed monochrome structure overlayed with much more general color info.

 

In terms of evolution, cones developed after rods; perhaps a survival asset. Our vision with 120 million rods (Luminosity/BW) is more acute than our color with cones at 8 million. Rods work in daylight for orientation, object recognition, motion and mapping. The color we see is distributed over the rod matrix of the scene. As Color is not as sharp as BW and the difference is made up by the brain; think watercolors.

So, our attention to BW may be based upon its correspondent structural aspects of our brain processing. We are seeing with that rod-experience while we are seeing color, but color overwhelms it. Take the color away...we are tapping into pure rod vision; more essential to us than color. The gnat's-ass sharpness is not necessary for color. Color is for identifying the chemistry reality; what colors do for identifying materials for their effect on our survival. Rods help you find food and not be food.

Now...toss in genetic make-up, 4,000,000 years of hard-wired and acquired survival behaviors, and what we do with that rod data has a very special connection, though somewhat concealed from our awareness.

 

Our rods are sensitive to luminosity, how bright and how dark an experience is and, therefor, contrast. Cones are sensitive to qualitative color but doesn't care about movement. Two colors can have identical luminosity but one can appear brighter than another. For example when a red hue and a blue hue have the same brightness, the red seems brighter. That said we are talking about two different kinds of contrast. A color image reduced to rods luminous response can conflict with that of the color response. Artist do interesting thing with that, especially the Impressionists.

I will define low light as light below which we see color; we are only using rods and not cones.

 

The whole thread is being defined as we speak. so, yes, low light is self-defined. If I knew the answer to h initial thoughts that started the thread I would not be asking these questions.

As for movement; out rod-acquired data is not merely a mono-chrome sensitivity but a consequence of the way the matrix of cones responds to differences. Rods next to each other do not all respond to stimuli the same way. Rods proximate to an excited rods will also reduce their response in order to render detail, through the messaging determined by the ganglion and bi-polar cells that shape data to the brain.

This performance, as light and detail moves across the matrix, makes rods and their data reveal movement. Cones do not have the density of rods so do not reveal the acute detail. The most primitive processing of rods, pre-dating the development of cones, reveal movement, object identification, spatial orientation, and scene mapping.

Cones do none of this. It has been suggested that cones, the evolutionary step after rods, respond to the variety of wavelengths and "create" color that has no actual presence in reality. The "color" we see, fabricated by our brain for use in a certain kind of distinction, has evolved to identify chemical values useful in survival.

 

Yes, and it is suggested that these were, functionally, rods as they rendered only a monochrome experience. Color started to evolve as different chemicals in different rods developed and, having two separate sensitivities to light, laid the foundations for color.

We can do this forever as the research is developing but 540 million years ago in fishes:

Vertebrate rod photoreceptors are thought to have evolved from cone photoreceptors only after the divergence of the jawed and jawless fishes, but this idea is questioned by new evidence that the short ‘cones’ of jawless sea lampreys are physiologically equivalent to rods..

Huge number of references but this one sorta hits the mark:

• Lamb T.D.

Evolution of phototransduction, vertebrate photoreceptors and retina.
Prog. Retin. Eye Res. 2013; 36: 52-119

It is a fascinating topic.

 

Photography is not possible without vision and vision is not possible without light and the ability to process it. How we process light is key to how we process 2 dimensional representations in our work. Different parts of our visual processing are sensitive to different aspects of light in service our our vitality.

Monochrome underpins all of our vision. Color gives us added ability to make discriminations but it is elaborated over the underpinnings of monochrome. Think watercolors over an ink outline with 3 dimensions.

 

I've heard you say that before and will not argue the point. That said, do these same expressed color events occur when we look at a B&W image?

 

Blood on the ground or a potential mate is jaundiced and therefore rejected come to mind. I imagine we can find many more.

 

Our rods do that:

As for movement; our rod-acquired data is not merely a mono-chrome sensitivity but a consequence of the way the matrix of cones responds to differences. Rods next to each other do not all respond to stimuli the same way. Rods proximate to an excited rod will also reduce their response in order to render detail.

This performance, as light and detail moves across the matrix makes rods, and their subsequent data through the messaging determined by the ganglion and bi-polar cells that shape data to the brain, reveal movement. This acute isolation also facilitates a sensitivity to edges and lines, which leads to object identification.