On Learning Blender

I’ve been using the GIMP recently to draw some things, and I’ve discovered that there are some things that it can’t do easily. Specifically, I want to draw a three dimensional scene, and that requires textures and other images to wrap around objects in the main image. Like, for example, the label on a can of beans. While this is possible in the GIMP, I’ve not been able to produce really convincing wrapped objects in the GIMP. This is almost certainly my fault and not the program’s fault, of course.

Anyway, I started looking at alternatives, of which there are many. Few of them are free, but one of the best, according to my research, is Blender.

The GIMP doesn’t pretend to be a painting program. It is as its name says, an Image Manipulation Program. (The G stands for “GNU”, which I will not explain. I will refer you to Wikipedia instead.) So, it’s main purpose is to take an image, perhaps a photograph, remove any blemishes, any unwanted photo-bombers, and apply effects and merge images to form composite images.

One task that can be achieved pretty easily in the GIMP is creating text strings and positioning them on top of images. That is great for creating book covers, for example, and I’ve created a few using the GIMP. It is great for two dimensional tasks, but is not designed for building things in three dimensions.

A book cover created using the GIMP
A book cover created using the GIMP.

Blender, on the other hand, is designed for creating three dimensional images. You can even fly or walk around them. A cube looks like a cube, a sphere appears spherical. You can see an example of the layout of the Blender screen at the head of this post. Unfortunately, reducing the Blender screen to this size makes it almost unreadable, but the cube can easily be seen.

So, Blender. I decided to try to learn Blender with the aim of creating images of three dimensional objects and “painting” them with two dimensional images to produce the effects that I wanted. I could then “render” them in Blender to produce images of the objects that I wanted, and then I could import them into the GIMP.

Blender is complex! Even the methods of navigating around the work area needed hard work to get my head around, and actually creating anything more than a simple primitive object such as a cone or a cube is hard.

If you go to YouTube and search for tutorials on Blender you will find literally dozens of them. I came across a series of basic tutorials which numbered forty one. If you perform an Internet search, there are thousands of Blender tutorials. It’s a very complex program.

It also has a quirky and very complex interface. For example, it doesn’t prompt you to save your work on exit, like many other programs, but if you forget to save, it has a way to recover your work from the previous session. This infuriates many people, and a search through the arguments for and against this feature can be entertaining.

Another quirk is that the “select” function is driven by a mouse right button click rather than the more usual left button click. This feature at least can be switched off if the user wishes.

Blender is most easily “driven” using hot keys, though the menus are there. There are so many hot keys and combinations of keys, that they are hard to remember. What does pressing Shift plus Ctrl plus the letter L do, for example? I don’t know, but it is probably something useful.

Anyway, I’m going to try to learn it, and I probably post some of my experiences with it here. So long, I’m off to read a 1900+ page PDF on Blender. It’s a beginner’s guide!

Please read my books. The paperback versions can be found Amazon, and the eBooks can be found there or at your favourite eBook store. I mainly write fantasy fiction.

 

Spring is here!

Bursting buds
Bursting buds

It’s officially spring and things are starting to warm up. Funnily the temperatures have not changed much, but it feels a lot warmer. The chrome sharp acid edge of winter has gone leaving a more bearable softer edged coolness behind. Lyrical words for a lyrical season.

Spring in this part of the world means waves of damp weather coming from the west. A cyclone, a normal one, not one of the monsters that cause devastation, may throw off several fronts as it approaches or passes over us, and we receive several burst of rain.

Water on grass
Water pearls on grass

This year, we have had a wet winter and things are tending to be a bit boggy and muddy. It makes it much harder to keep things clean as the mud tracks indoors. This is particularly bad if you have a dog who think mud is for rolling in. Fortunately our pooch is not one of those.

The wet spring weather means spending time indoors, unless you are prepared to don wet weather gear and brave it. We look forward to the burst of spring sunshine between the bands of showers. Showery weather means clouds and while the sky may be grey, it is not the depressing slate grey sky dispensing drizzle that I remember from England.

Kereru
Kereru or New Zealand Pigeon

The intervals of blue sky should become longer as spring progresses but they are welcome however brief. The enable one to get out and about, to note all the buds bursting from the trees and birds, particularly Tuis, dashing about defending territories, chasing off other birds and generally singing their hearts out.

Some trees have already blossomed and are now presumably in the process of fruiting. I’ve watched fruit trees in the garden throw out blossoms only for the blossoms to fall almost before I can get into the house for my camera! Some flowering cherries have been masses of blossom and are now merely green.

White cherry blossom
White cherry blossom

The pale green of new shoots is a unique colour, contrasting strongly with last year’s foliage which is a much darker colour. This changes the character of the light for photography, but the effect doesn’t last long. The new shoots rapidly lose that unique tinge, even if they are not yet as dark as the last year leaves.

The grass also grows strongly at this time. Paths which were mere tracks are now corridors between rapidly growing walls of grass. Much of this new grass will shortly pause, flower, seed, then turn yellow brown and die back. Fortunately I don’t suffer from hay fever, but during the flowering phase suffers with curse the wind blown pollen.

Fir trees
Fir trees

It’s not just grass that lets loose a volley of pollen. There are no fir trees near where I live, but the wind screen of my car, the edge of the lingering puddles and other sheltered spots develop a yellow edging from the pollen of fir trees kilometres away.

There’s a surprisingly sizeable population of ducks in this suburban area. The reserve and parks all seem to host a few ducks, and they even visit gardens in the area. It’s breeding season for the ducks, with all the raucous clamour that that entails. It’s sometimes difficult to know whether they are courting or fighting.

No ducks!
No ducks!

Good spring weather brings out the lawnmowers. I’m not sure that the ground isn’t a bit too wet at the moment as things are still pretty boggy. In the reserve which I and the dog visit the mostly frequently, the grass cutting has resulted in a mess of tyre marks and some areas where the grass is damaged by the mowers. It looks pretty bad, but for experience I can say that marks will be undetectable in a week or two.

I’ve not seen many insects this year yet, but they must be around as I’ve seen the Welcome Swallows around twisting and turning and catching insects in the air. They are called “Welcome Swallows” because they appear at the beginning of spring, heralding the better weather to come.

Sacred Kingfisher
Sacred Kingfisher

I’ve not seen the kingfisher recently where I usually see him/her in our local reserve. He/she has been about in the last weeks though, so I shall probably see him/her soon. The full name for the Kingfisher is the Sacred Kingfisher. It’s called “sacred” because it is said to holy to the Polynesians.

I like the bird’s original binary classification name of “Halcyon sancta”. “Halcyon” can mean calm, peaceful, happy or golden. “Sancta” means sacred of course. “Sacred peace”. The drug halcion is used to induce sleep or relaxation and there is possibly a connection between the two words. Unfortunately the binary classification name of the bird has been changed and it is now the less appealing “Todiramphus sanctus”.

Winter clothing
Winter clothing

One advantage of spring is that we can start to discard the multiple layers of clothes that we are forced to don over winter. I hate piling on the sweaters and overcoats, changing shoes and so on that going out in the winter involves. Every layer that I can leave off is a cause for rejoicing. Unfortunately the fickle weather of spring with the occasional cold snap means that tomorrow I might have to layer up again.

Today the weather is a bit grey. It’s not too cold. Later on it is forecast to be showery again. That’s OK because I know that better weather is coming. The weather will be up and down for a while, it’s true but the ‘ups’ will get more up and the ‘downs’ will be less down, and before we know it, the t-shirts and shorts will be out, we’ll be looking forward to summer.

Grey weather
Grey weather

Spring is a turn around season, where we say goodbye to the fierceness of winter and look forward to the mellowness of spring. No more chopping of wood and lighting fires, cold draughts through small cracks and mounds of bedclothes to keep us warm. No more donning layer upon layer of clothes when leaving the house. It’ll be back to open windows, time in the garden and much lighter bedclothes, and just picking up the car keys when we leave the house.

Surrey woods near Walton on the Hill
Surrey woods near Walton on the Hill

Photography – Yet Again

Gum Grove path
Path to Gum Grove

I wondered if I had ever written a post about photography. So I checked. The answer was that I’ve done quite a few. Oh well, it’s a big subject!

I don’t count photography as a hobby of mine, but more as an interest. I’ve got a camera, but it is only an enhanced point and shoot, and I sometimes even use the camera on my cellphone. I haven’t bought any camera gear and I probably won’t. Handheld is good enough for me.

Of course photographer want the best picture that they can get, so better cameras and lenses are the way to go, and probably a tripod would be the next buy. Special filters and accessories enhance a photographers art and this can get expensive. Not to mention bulky and hard to carry around.

Fungi
Old and New

I have nothing but admiration for those photographers who will hike kilometres and wait for hours for the right light to capture a particular shot. I’m usually constrained by a number of things that need doing, plus I usually have a dog attached to me when I have the opportunity to snatch a picture.

Nevertheless I try to take good pictures. I might spot the opportunity of a picture and I wrap the dog’s lead around a convenient tree while I compose and take whatever has caught my eye. I usually take a few shots of the same subject to enhance the possibility of one of the pictures being an acceptable one.

First Bridge
First Bridge

Usually I don’t fiddle with the camera settings, some of which are meaningless to me anyway, but occasionally I will experiment with the shutter timings and the aperture settings. I say “shutter” but I’m pretty sure that my camera doesn’t have a shutter.

I have to trust the autofocus as there is way on my simple camera to easily adjust the focus. I can lock in the distance setting by partially pressing the button, and I have done so in the past, with variable results.

Lichen on trees
Lichen on trees

One consequence of the digital revolution is that the potential picture is displayed on a LCD screen rather than through a viewfinder, and these are often difficult to see and compose a picture in. I sometimes take a few pictures of my subject from different distances and different angle, but composing a picture is still difficult.

Fortunately my camera is pretty clever, and the focussing is usually better than I expect. Composition is pretty hit and miss for the reasons I mention above. Usually there is at least one photograph from the many that I take which is acceptable and many are better than I could hope for from my somewhat random shooting method.

Kereru
Kereru on New Zealand Pigeon

It’s not quite a “Monte Carlo” method of taking photographs, but it is close. It’s not often that I get a picture which is better than merely “good”. But even then the picture will not be razor sharp, and serious photographers would probably look down on them. That’s OK, as I don’t aspire to having them blown up to A4 or even A3 and hung on a wall.

So, why do I take photographs? Well, I do post a lot of them on Facebook, so I must feel the need to get others to look at them, and hopefully they will like them and if they like them or don’t like them, hopefully they will say so.

Above the bridge
The stream from above the bridge

My Facebook pictures are public, but most comments come from friends and family, which is understandable as I don’t do anything to publicise them. When friends and family comment on them, others may see the pictures so they do find their way out there.

Facebook and other “social networking” apps have changed photography for me and for millions of others. Without Facebook taking a photograph of oneself is a bit pointless. Who would ever see it? But “selfies” allow the photographer to include his/her self into a picture.

First Bridge
The First Bridge

It’s a form of bragging. The selfie taker is boasting : “Here am I and here are my friends, and we are having fun, in this indiscernible location, and we are drunk as skunks”. OK, well, some selfies are taken in recognisable places and the selfie taker is not under the influence of alcohol, but many, many are.

So the pictures that I and other serious and not so serious photographers post to social media are usually not selfies and most often don’t contain babies, other children, pets and people grinning at the camera. The pictures that I and other posts are in the minority, and of course there is a huge number of pictures that fall into both categories, the trivial and the hopefully not so trivial.

Autumn Colors
Autumn Colours

For instance, the pictures of dogs running where you can’t see their legs and so they appear to be floating are funny, essentially trivial, but make a good photographs, even if it transpires that the pictures were serendipitous. The stunning picture of a sunset taken on a honeymoon, may be snapped on an iPhone, and is arguably less trivial.

I mostly like to take pictures of fungi, flowers and trees, not to mention insects and other small animals. I see beauty in a spider or beetle or slug and often try to bring this out in my pictures. Also in fallen leaves or leaves with autumn colours, or the small flowers that others refer to as weeds, but which repay a closer look. Often the structure of such small plants is amazing.

Basket Fungus
Basket Fungus (Ileodictyon cibarium)

I also take pictures that I think of a “records”. Such as the time when the stream turned into a raging torrent during a big storm, or the moment when a Monarch butterfly hatches from it pupa. While some of these may transcend being a record of the event, many are interesting but less of a photograph and more of a picture. The lighting many be wrong and the image fairly dark, but it still shows the insect expanding its wings from mere sacks to the beautiful wings of the complete insect.

There’s nothing wrong with selfies and other similar photographs, but one would hope that the selfie taker would graduate to something better eventually. If what I might term a “proper” photograph is actually better in any real way.

Large Fungi
Large Fungi

Photography, Ancient and Modern

19th century studio camera, with bellows for f...
19th century studio camera, with bellows for focusing (Photo credit: Wikipedia)

When I looked up the date when photography was invented I was surprised that it was first tried in 1800, if you allow the word to mean the capturing by some means or other an image created by some means or other!

While optics were known and understood well before this time, no one apparently thought of using glass to create images of views, people or anything else. If they did, there appears to be no record. Also the technology didn’t exist to record any image so created, so it would have been pointless to do so anyway, though artists may have been able to benefit from an image projected onto a canvas as a guide.

The geometry of a pinhole camera as seen from ...
The geometry of a pinhole camera as seen from the X2 axis (Photo credit: Wikipedia)

So before “the camera” we had “the camera obscura”. A camera obscura is basically a darkened room with an image created by a pinhole camera projected onto a white screen.  They are fascinating to visit and I highly recommend visiting one.

When the means for creating an image (a lens) came together with a means of capturing the image photography was born. At first the techniques were hit and miss with wet plates coated in chemicals to capture the image and simple lens to create the image, and a long exposure time.

Brownie2 lens
Brownie2 lens (Photo credit: Wikipedia)

But techniques and technologies quickly improved and exposure times came down. In the early days, when sitting for a photograph, the long exposure times meant that braces had to be used to prevent the sitter from inadvertently moving and spoiling the photograph.

The image of a photographer in those days was of a man hiding under a dark cloth doing mysterious things with his camera, maybe firing off a tray of flash powder to record the image on a glass plate, then dashing off to his “dark room” to process and fix his image onto the glass plate with dangerous chemicals. The end result was an image with light and dark reversed, a so-called “negative”.

New dark room, Boston Camera Club, Bromfield St.
New dark room, Boston Camera Club, Bromfield St. (Photo credit: Wikipedia)

Some of these early cameras were works of art, with shining brass trimming, great leather bellows and polished wood bodies and plate holders, all mounted on a substantial tripod. Great brass screws could move the lens closer to or further from the body which held the plate and often could move the lens up and down or from side to side to compensate for perspective distortions.

Several things eventually brought photography in reach of the man in the street. Firstly, it became possible to record the images onto a strip of plastic, which meant that the camera only had to be loaded once in a while. At the same time, it became possible for you to hand your film to the local chemist or apothecary and have the films developed and positive images printed on cards.

English: J. J. Williams, Portrait of Hawaiian ...
English: J. J. Williams, Portrait of Hawaiian woman. Print from glass plate negative. (Photo credit: Wikipedia)

The rise of mass production allowed cameras to be produced very cheaply, and the Box Brownie arrived, costing two British pounds. Anyone could be a photographer. To be sure corners had to be cut, so the Brownie was a simple box with small and very simple lens, and the shutter was simply a plate that usually blocked light from entering.

On pressing the shutter lever a spring was tightened until the plate flicked over, giving the lens a brief look at the outside world. The film strip was held on one spool and transferred to another. A window in the back of the camera showed the backing strip of the film and you would the film on until the next number showed in the window.

Kodak SIX_20 'BROWNIE' E
Kodak SIX_20 ‘BROWNIE’ E (Photo credit: Wikipedia)

The user aimed the camera by using a crude “viewfinder”. This was simply a window in the top of the camera which allowed the photographer to look down on a tiny mirror which reflected the view in front of the camera. It was around a centimetre wide and pointed only more or less in the same direction. To switch from landscape mode to portrait mode you turned the camera over and looked into a similarly minute viewfinder!

Of course things rapidly moved on from there. People loved the Box Brownie and soon handheld cameras of all sorts appeared. Some had two linked lens arranged piggy back style as in the Rollieflex, and some had a single lens, like the Hasselblad. Those two were high end machines, and featured switchable components and high quality lenses and other accessories. They tended to be favoured by professional photographers.

Hasselblad 500C
Hasselblad 500C (Photo credit: Wikipedia)

Most other cameras were built on a different design, though. Most featured a eye level viewfinder, and cheaper ones usually didn’t have interchangeable accessories. Most moved away from the spool to spool system to the 35mm cassette. Really cheap cameras eventually had a drop in cassette system.

Two other big changes were the introduction of colour film and the single lens reflex system. Many photographers used to monochrome film were appalled by the advent of colour film and swore never to change to it. Most amateurs adopted it with enthusiasm of course. Eventually everyone (almost) used colour.

Empire-Baby camera
Empire-Baby camera (Photo credit: Wikipedia)

The single lens reflex system allowed the photographer to see exactly what he was shooting as the viewfinder looked through the same lens through which the image was captured. Generally the viewfinder was eye level but the Hassleblad was an exception retaining the waist level view point.

The more expensive cameras had knobs, dials and buttons all over them, but the cheaper varieties had only a few, and some did not have any controls. All used film cassettes and most had flash devices for low light level conditions.

English: A very popular collectible made even ...
English: A very popular collectible made even more popular by its appearance in the 2nd Harry Potter movie. This is just a cool camera, from its impressive dials and gears, to its nifty two-tone skin and bright chrome trim. This example is shown topped with the clip-on selenium meter. Because of its shape (and weight), the Argus C3 is affectionately known as “The Brick”. Made from 1958-66. Polski: aparat fotograficzny Argus C3 Matchmatic (Photo credit: Wikipedia)

Then along came digital. Film disappeared, to be replaced by flash storage. Most cameras lost their viewfinders, which were replaced by small screens covering the whole of the back of the camera. Many settings could be set using the screen and a few buttons, and the cameras sizes shrunk. Some these days are credit card size.

But now, it seems that the so called “compact digital cameras” have briefly had their day. Every smartphone has an embedded camera, and people are not buying the compacts. Some smartphones now come with Leica lens technology.

English: Leica III camera with both the Clear ...
English: Leica III camera with both the Clear and Amber lens attachments. (Photo credit: Wikipedia)

The result? Billions (if I’m not mistaken) of absolutely atrocious photographs spamming the Internet. From cute cats to drunken revellers, everything is now floating around out these. But I’m optimistic. Real photographs and real photographers are still out there. Somewhere.

 

 

Imagine this….

Flying Swan
Drawn using Python and Matplotlib. This picture is serendipitous and not intended.

[Grr! While I finished my previous post, I didn’t publish it. Darn it.]

Since I’ve been playing around with computer generated images recently, my thoughts turned to how we see images. When you look at a computer or television screen these days, you are looking at a matrix of pixels. A pixel can be thought of as a very tiny point of light, or a location that can be switched on and off very rapidly.

Pixels are small. There’s 1920 across my screen at the current resolution, and while I can just about see the individual pixels if I look up close, they are small. To get the same resolution with an array of 5cm light bulbs, the screen would need to be 96 metres in size! You’d probably want to sit at about 150m from the screen to watch it.

A closeup of pixels.
A closeup of pixels. (Photo credit: Wikipedia)

The actual size of a pixel is a complicated matter, and depends on the resolution setting of your screen. However, the rating of a camera sensor is a different matter entirely. When I started looking into this, I thought that I understood it, but I discovered that I didn’t.

What complicates things as regards camera sensor resolutions is that typically a camera will store an image as a JPG/JPEG image file, though some will save the image as a RAW image file. The JPG format is “lossy” so some information is lost in the process (though typically not much). RAW image file are minimally processed from the sensor data so contain as much information about what the sensor sees as is possible. Naturally they are larger than JPG format images.


Embed from Getty Images

When we look at a screen we don’t see an array of dots. We pretty much see a smooth image. If the resolution is low, we might consider the image to be grainy, or fuzzy, but we don’t actually “see” the individual pixels as such, unless we specifically look closely. This is because the brain does a lot of processing of an image before we “see” it.

I’ve used the scare quotes around the word “see”, because seeing is very much a mental process. The brain cells extend right out to the eye, with the nerves from the eye being connected directly into the brain.

Schematic diagram of the human eye in greek.
Schematic diagram of the human eye in greek. (Photo credit: Wikipedia)

The eye, much like a camera, consists of a hole to let in the light, a lens to focus it, and sensor at the back of the eye to capture the image. Apparently the measured resolution of the eye is 576 megapixels, but the eye has a number of tricks to improve its apparent resolution. Firstly, we have two eyes and the slightly different images are used to deduce detail that one eye alone will not resolve. Secondly, the eye moves slightly and this also enables it to deduce more detail than would be apparent otherwise.

That said, the eye is not made of plastic metal and glass. It is essentially a ball of jelly, mostly opaque but with a transparent window in it. The size of the window or pupil is controlled by small muscles which contract or expand the size of the pupil depending on the light level (and other factors, such as excitement).

English: A close up of the human eye. Notice t...
English: A close up of the human eye. Notice the reflection of the photographer. (Photo credit: Wikipedia)

The light is focused on to an area at the back of the eye, which is obviously not flat, but curved. Most the focusing is done by the cornea, the outermost layer of the eye, but the lens is fine tuned by muscles which stretch and relax the lens as necessary. This doesn’t on the face of it seem as accurate as a mechanical focusing system.

In addition to these factors, human eyes are prone to various issues where the eye cannot focus properly, such as myopia (short sightedness) or hyperopia (long sightedness) and similar issues. In addition the jelly that forms the bulk of the eye is not completely transparent, with “floaters” obstructing vision. Cataracts may cloud the front of the cornea, blurring vision.

English: Artist's impression of appearance of ...
English: Artist’s impression of appearance of ocular floaters. (Photo credit: Wikipedia)

When all this is considered, it’s amazing that our vision works as well as it does. One of the reasons that it does so well is, as I mentioned above, the amazing processing that our brains. Interestingly, what it works with is the rods and cones at the back of the eye, which may or may not be excited by light falling on them. This in not exactly digital data, since the associated nerve cells may react when the state of the receptor changes, but it is close.

It is unclear how images are stored in the brain as memories. One thing is for sure, and that is that it is not possible to dissect the brain and locate the image anywhere in the brain. Instead an image is stored, as it is in a computer, as a pattern. I suspect that the location of the pattern may be variable, just as a file in a computer may move as files are moved about.

Expanded version, with explanations.
Expanded version, with explanations. (Photo credit: Wikipedia)

The mind processes images after the raw data is captured by the eye and any gaps (caused by, for example, blood vessels in the eye blocking the light). This is why, most of the time, we don’t notice floaters, as the mind edits them out. The mind also uses the little movements of the eye to refine information that the mind uses to present the image to our “mind’s eye“. The two eyes, and the difference between the images on the backs of them also helps to build up the image.

It seems likely to me that memories that come in the form of images are not raw images, but are memories of the image that appears in the mind’s eye. If it were otherwise the image would lacking the edits that are applied to the raw images. If I think of an image that I remember, I find that it is embedded in a narrative.

Narrative frieze.
Narrative frieze. (Photo credit: Wikipedia)

That is, it doesn’t just appear, but appears in a context. For instance, if I recall an image of a particular horse race, I remember it as a radio or television commentary on the race. Obviously, I don’t know if others remember images in a similar way, but I suspect that images stored in the brain are not stored in isolation, like computer files, but as part of a narrative. That narrative may or may not relate to the occasion when the image was acquired. Indeed the narrative may be a total fiction and probably exists so that the mental image may be easily retrieved.

One bubble memory track and loop
One bubble memory track and loop (Photo credit: Wikipedia)

 

Seeing things


Embed from Getty Images

I sometimes suspect that I return to the same topics time and again. Not too often I hope, because that will put people off reading this blog (in case anyone does!) This is possibly a topic which I may have already addressed, but hopefully this post will be interesting anyway.

It seems obvious to me that we all see things differently, and I’m talking about vision here, not “seeing” as a philosophical point of view. Some are short sighted, some long sighted, and others have impaired vision. I see a colour as a shade of blue, while my wife sees it as a shade of green.

Toyota Celica 2.0 GT (ST202) shown in Bright T...
Toyota Celica 2.0 GT (ST202) shown in Bright Turquoise Pearl (colour code 756). (Photo credit: Wikipedia)

One could argue that the difference is merely where the line is drawn, but I think that it is more than that. Apart from the physical differences in the lenses of our our eyes, we may have differences in the physical structure of the rest of our eyes, perhaps in the rods and the cones, and it is highly likely that the physical structures of our brains are different, and our minds (which I think of as the software that runs of the hardware of the brain) are definitely different.

It’s no surprise then that my wife and I disagree on whether a colour is a shade of blue or of green. (Actually we disagree about a lot of things. I believe that it goes with being married for 40+ years!)

Plymouth Valiant 100 of some 40 years ago seen...
Plymouth Valiant 100 of some 40 years ago seen on street in New Orleans (Photo credit: Wikipedia)

In Googling around as I write this post I found an article about the brain’s colour processor. Interestingly it has a section entitled “Color is Personal” which is a part of my theme for this post. This section, however, is not really relevant to my theme as the author then discusses Achromatopsia, where damage to the colour processor causes all sensation of colour to disappear.

It seems that even in our own brains and thinking processes the idea of colour is not fixed. I read another article which describes our own personal perception of colours as “malleable”. The implication of this is that a person might describe a colour as “a shade of green” one day, and “a shade of blue” on another day. Is there no hope of a definitive answer?

Newton's color circle, showing the colors corr...
Newton’s color circle, showing the colors correlated with musical notes and symbols for the planets (Photo credit: Wikipedia)

A physicist could help us out, couldn’t he/she? He/she could measure the frequency of the light and say, definitively, that the colour is blue, or it is green, couldn’t he/she? Well, sort of. This would work for very simple colours, but real world colours are rarely made up of just one colour. The scientist’s scope would likely show a range of frequencies resembling a mountain range. That blue/green colour might have traces or red or violet, and is fairly certain to have more than one peak in the blue/green range.

Albert Einstein showed us that if a scientist was moving at a high speed relative to us, he/she would measure the frequencies in the colour differently from a scientist whose spectroscope was alongside us and not moving or moving at the same speed as us.

General Relativity
General Relativity (Photo credit: Wikipedia)

The ambient light has an effect on the colours that we perceive. A red object in red light doesn’t look red. Other objects of different colours look different in a red light. Similarly, it is difficult to determine the colours of cars and other objects under the yellow/orange sodium lights. According to Wikipedia, the colour of a street light has effects other than simple colour perception – it appears to affect peripheral vision.  New LED technology may be able to remove some of these deficiencies.

There are innumerable effects which affect or perception of colour. The most recently famous illusion is the dress which appears to people to be either black and blue or white and gold, but there are many such illusions. One which I came across a long time ago is the chessboard illusion. In this illusion, two square appear to be different colours, but are in fact the same colour. This illusion is usually shown in monochrome, but the illusion works in colour too, and depends on the shadow of the cylinder to produce the effect.


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One brain is very like any other brain. When a scientist shows someone a colour on a card, the same areas of the brain show activity in all individuals, if we exclude some cases where brain function is abnormal for some reason. We can’t delve very much deeper into this issue as we don’t know what this activity signifies, beyond the bare fact that the person was shown a card with a colour on it. We certainly can’t tell if they see it as a shade of blue or a shade of green, and we can’t tell what their subjective experience is when the brain activity occurs.

In some individuals a number or letter may invoke a sensation of colour. Such people might have the sensation of seeing something green when they think of or read the number 6. I don’t know if this imprinted behaviour because the person was presented with a green symbol when first learning their numbers or whether or not it was merely a chance association that arose at a different time, or indeed if it was because of some neurological happening or trauma that has allowed the association to happen.

English: A graph or how the brain interprets color
English: A graph or how the brain interprets color (Photo credit: Wikipedia)

Anyhow, when we see something, there are many stages to the process that  starts with light leaving the object, reaching our eyes, being refracted by the lens of the eye to form an image on the retina at the back of the eye, being sensed by the rods and cone cells in the retina, and sending signals to the brain, which then processes the data.

The amazing thing here is that the image sent to the brain is pretty messy. The eye is not a perfect sphere, the retina is curved in three dimensions and the resolution is pretty rubbish. The retina has at least one major gap in it, rods and cones are not evenly distributed across the retina. Our perception however, is smooth and break free. We have our image processing hardware and software in the brain to that for that.

Retinoblastoma retina scan before and after ch...
Retinoblastoma retina scan before and after chemotherapy (Photo credit: Wikipedia)

It means we can watch a soccer match, and we can see the black and white panels or the ball rotating as it spins across the television screen, when the unprocessed image that reaches our eyes may be quite blurred. Seeing is believing!


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