SAGA OF COLORS

SAGA OF COLORS

            Speaking of colors is not as simple as it seems! It intertwines physics of light, the physiology of vision and our psychological perceptions. Colors have been used in psychology for mental and physical healing. They have been used across almost all cultures and countries to represent certain beliefs and ideas. For example: Indians consider white as the color representing peace, saffron for sacrifice, green for happiness and likewise red has been considered as the color for danger all over the world and hence it is used in painting danger boards, important instructions that are not supposed to be missed etc., Although many such things are formulated based on aesthetic appeal made by the color, some have scientific explanations too, which I will be covering in this article. Similarly, we will also discuss the role of colors in science, entertainment, psychology, photography, art.

Colors intertwines physics of light, physiology of vision and our psychological perceptions

            In order to understand those we need to know the basics of colors, like, how can they be defined scientifically? And classification of colors, nomenclature of colors and so on... which we will be discussing under “Theory of colors”.

Theory of colors:

The adjacent image is called the color wheel and can also be considered as a derivative of HSV which is a popular way of representing colors. Anyways, we will discuss the basic idea first.

Colors can be considered in three sets which you may call as primary colors. The set one considers as primary depends on the application and situation.

RGB (Red / Blue / Green), CMY (Cyan / Magenta / Yellow), YRB (Yellow / Red / Blue)
RGB is used by most electronic and transmissive-light technologies such as TV and film, and CMY (actually CMYK including Black) is used with reflected light technologies such as printing inks.
When it comes to color mixing we can take any one set of first-order colors and produce 9 sets of second-order which then total the sum of colors to 12. Of course we can produce hundreds of thousands of colors by mixing various proportions of primary colors, again here, we are only discussing about basics.
Though traditionally RGB is considered as primary colors, we in this discussion take up YRB for producing second-order colors just to compound the statement that any set can be taken as first-order colors.
Blue                             Primary
Blue-Violet                 75% / 25% mix of Blue and Red
Violet                          50%/50% mix of Blue and Red  
Red-Violet                   25% / 75% mix of Blue and Red
Red                             Primary
Red-Orange                 75% / 25% mix of Red and Yellow
Orange                       50%/50% mix of Red and Yellow
Yellow-Orange           25% / 75% mix of Red and Yellow
Yellow                                    Primary
Yellow-Green             75% / 25% mix of Yellow and Blue
Green                          50%/50% mix Yellow and Blue
Blue-Green                 25% / 75% mix of Yellow and Blue

Complementary colours:

                A complementary color is an important idea in perceiving colors as it tricks our eye. Before elaborating the idea, it has to be known that a complementary color for a specific color in the color wheel is the one which is directly opposite to it in the same wheel. And technically, a complementary color for a primary color is the one which is produced by mixing the other two colors in the set chosen. For example: 

Complementary color for red is cyan as shown in the figure.

An anaglyph movie requires a complementary color set to produce a 3-D effect.

Consider the film shown below. When you wear anaglyph glasses which has red and cyan filters for left and right respectively, the shade of red in the picture is filtered by red filter and only cyan is visible and similarly for the other eye, the shade of cyan is filtered and only red is visible. These two images intercepted by two eyes in two different ways with regard to the position of colors in the picture.

NASA has used the anaglyph picturing technology(as shown above) to map surface of mars in its various rover missions in order to enable scientists and researchers, a 3D view of terrain. 

These days in picturing 3D movies, technique of polarisation is being used which works this way- film is shot using two cameras resembling our two eyes one capturing the picture in vertical polarisation and other, horizontal polarisation. While viewing, audience will be given goggles which has vertical polarity filter for one and horizontal for the other. This way, a perfect 3D image is produced. This has been in practice since 1958, though!

Some interesting facts about complementary colors:

1.      When you stare at a certain object (of a primary color) for long and divert your suddenly, you will notice the same object flashing before your eyes but with a complementary color.

2.      When you observe the shadow formed by an apple, you can observe the hint of its complementary color.

3.      Complementary colors when seen together in equal proportions compounds their brightness. Examine the adjacent pattern:

While anaglyph is a popular practice to represent 3D on 2D, another popular method is stereogram which require no equipment to watch 3D effects.

How does a stereogram work?

            Stereography (stereo=repetition) is a scientific way to represent 3D in 2D which requires no instruments but tricks on how to look at a stereogram. The illusion of depth in a stereogram is made by intelligent mixture of color combinations and vision physics. A stereogram consists of a repeated pattern of images or textures in which the distance with which the pattern repeats is considerable (too high nor too low).

            When we try to look at something we try to focus both of our eyes in unison onto that particular thing. And now if the object is close enough, try closing watching the object with one eye closed at a time, what you watch is linear displacement in the position of the object w.r.t your eyes. Now, in order for you to feel 3D effect on a 2D paper, we need to provide the eyes with two displaced images of the same object (the same way we perceive in reality). In order to do that, stereo grams have repeated patterns. When you try to focus on some object (imaginary) which is behind the stereogram you are looking at, we observe our eyes processing the displaced images together. And now if such displaced images have a coincidence in patterns, we can feel a 3D or reality effect in a 2D picture.

           

Try the above stereogram and feel the 3D for yourself.

Guidelines:

1.      Do not focus on the image as such. Instead, imagine a hypothetical object behind the image and look at that.

2.      If you feel you are having two images before you, linearly displaced, it is good, you are looking in the right way.

3.      For good results try looking through the center of the image.