Tuesday 22 November 2011

COLOUR THEORY LECTURES 1 +2 + NOTES


Here are the general points I took away from the lectures and further points of investigation I hope to carry out.





There are two different types of colour.. additive and subtractive colour. Additive colour is basically RGB colour and subtractive colour is basically CMYK colour. It may be more complicated than this, but as of now this is the main information I'll be dealing with.


additive colour = RGB colour
subtractive colour = CMYK colour


RGB colour is obviously to do with light, and is based around the concept of white, and the colours that make up light waves. i.e. white. Isaac Newton back in the day found this out when he shined light through a prism and it split up the light into three principle colours: red, green and blue.


CMYK colour is where Cyan (C), Magenta (M), Yellow (Y) mix together to form Black (K). Sometimes called Key, or Kblack.


RGB colour is mainly based around screen, projectors, cameras, pixel based tools such as computer monitors. This is why RGB is used for web, so whatever colour you work with, it will display how it should and the colour won't change drastically. Similarly you should never work with CMYK colour modes, to produce work that will be displayed on the web. The different colour resolutions and colour modes of different monitors will make the colours work out differently.


CMYK is mainly to deal with print - offset printing, paints, plastics, fabrics, and photographic prints are all based on CMYK colour. Basically anything that comes out of a printer is CMYK colour. Most printers have seperate ink cartridges for C, M, Y and K. and mix them together to make pretty much any colour possible.


As it says in the E-Studio resource (probably explains better than me!)




"Additive Colour

An additive color model involves light emitted directly from a source or illuminant of some sort. The additive reproduction process usually uses red, green and blue light to produce the other colours. Combining one of these additive primary colors with another in equal amounts produces the additive secondary colors cyan, magenta, and yellow. Combining all three primary lights (colours) in equal intensities produces white.

Additive color systems start without light (black). Light sources of various wavelengths combine to make a color. In either type of system, three primary colors are combined to stimulate humans’ trichromatic color vision, sensed by the three types of cone cells in the eye, giving an apparently full range.

Subtractive colour
A subtractive color model explains the mixing of paints, dyes, inks, and natural colorants to create a full range of colours, each caused by subtracting (that is, absorbing) some wavelengths of light and reflecting the others. The color that a surface displays depends on which colours of the electromagnetic spectrum are reflected by it and therefore made visible.

Subtractive color systems start with light, presumably white light. Colored inks, paints, or filters between the viewer and the light source or reflective surface subtract wavelengths from the light, giving it color. If the incident light is other than white, our visual mechanisms are able to compensate well, but not perfectly, often giving a flawed impression of the "true" color of the surface."



It's really interesting to note that they're both the primarys and secondarys of each other. The secondarys of RGB are CMY and vice versa. how cool!



We also learned about colour terminologies and colour wheels and how each colour works with another. The three main types of colours are:

PRIMARY:
This depends on what type of colour system you're working with.

For additive colour the primary colours are R (red), G (green) and Blue.

For subtractive colour the primarys are C (Cyan) M (Magenta) Y (Yellow).

When light is split through a prism, the colours are sometimes called spectral colours which are ROYGBIV. These are often shortened to Red, Green, Blue/Violet. I learnt a nice little memorising thing in school:

Rip
Off
Your
Goolies
Before
I
Vomit


Red
Orange
Yellow
Green
Blue
Indigo
Violet


SECONDARY:
Secondary colours are the result of mixing two primary colours. For example Red and blue produce violet. Red and yellow produce orange. Yellow and blue produce green. Depending on what ratio of each primary you add you get different colours. For example a 'reddy yellow' or a 'bluey green'.

TERTIARY:
Tertiary colours are browns and greys, containing all three primary colours. They're created by mixing either all three primary colours or a primary and secondary color (secondary colours of course being made from two primaries). By varying the proportions of each primary color, you create the different tertiary colours.



COMPLEMENTARY:
Complementary colours are the colours opposite each other in the colour wheel. For example primary red's complimentary is primary green. Primary oranges complimentary is blue. Yellow's complimentary is Violet. 


CHROMATIC VALUE:
The 'lighter' a colour is, or the closer to white a colour is - the higher it's chromatic value. So for example pale yellow has a higher chromatic value than navy and black as it's lighter and closer to white than both.


Similarly black has a lower chromatic value than navy and pale yellow as it's 'darker' and further away from white than both.


HUE:
Hue is pretty much what we call different shades of colour. When we differentiate a cyan, from a turquoise or a navy blue. We are looking at different hues of colours blending together. Different hues are caused by different wavelengths of light, especially in regards to additive colour methods.


SATURATION:
Similar to chromatic value, where it deals with light and dark. A colour seeming lighter or darker in terms of how much light is hitting it. For example a colour on the wall, in a dark room would look different to a colour in a light room even though the colour on the wall hasn't actually changed but the amount of light hitting it. It looks as though someone just mixed more black, or white into the colour when you see it on screen/print. So it's easy to think of it in terms of light or dark, but really something should be weak in saturation or strong.






You can see here all the different shades of colour, as the colours go towards the outer edge, the chromatic value of the colour is increasing as they're getting lighter, or more 'whiter'.  In the middle area of all the colours in terms of the levels is probably the colours with the strongest saturation as they're the 'brightest',

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