mixing pigments versus mixing light

Short in cut, one is substance principle, another is add.

Oh, I see your problem is another rather than this.....

You mean if we would have divided the mixing pigment into very tiny parts, their particle would be arranged individually. so they would behave add principle? but why still shown subs in the whole unit? wow, interesting...

Im also waiting for right answer... May relate to statistic princile of bio.

or these particles overlap and they may impose on each other..

This is going to be tough to explain short but I will try. Color: to be able to see color you need 3 things: an object, an observer and light.

Light: light is electromagnetic energy, visible light occupies a very small part of the electromagnetic spectrum from about 400 nm to 700 nm, this range is known as the visible spectrum

Object: an object is anything that can reflect, transmit, absorb light

An observer is the person or instrument that sees the light reflected from the object

Any description of color must contain information about HUE, VALUE and CHROMA for the color communication to be complete.

Hue: describe the color, non hue color such as grey, black or white are called neutral or achromatic colors

Value: describes the lightness or darkness of a color. All colors have a value

Chroma: describes the intensity of the color. Words to describe the chroma: saturated, desaturated, clean an dirty. Neutral or achromatic colors do not have chroma.

It is useful to be able to describe a color using number instead. For a specific light source and observer XYZ values are used to describes a color. In general X is red Y is green and Z is blue

Recall that for a color to exist, you need light, an object and an observer. If any of these 3 items change, the color will change

Remember an object has color due to its various chemical compounds. Each color inducing compound has a distinctive curve when reflectance of light is plotted versus the wavelenght of the light. This curve is called spectrophotometric curve or spectral curve. The spectral curve is a "fingerprint" of the compound. In paint, the chemical compounds are called pigments.

When mixing light you don't have the reflection (or absorption) of the object or the pigment.

The human eye is not equally sensitive to all color of light in the visible spectrum. To create a model of the standard human eye, the sensitivity to red, green and blue monochromatic light was measure accross the visible spectrum. The experiment was conducted by illuminating one side of a white screen with a monochromatic test light of a specific wavelenght. Then a person was told to mix the 3 primary lights (red, green and blue) on an adjacent screen until the 2 lights matched. multiply this by 1000 and ou got a database known as the CIE Standard Observer.

The XYZ values vary if the light source, object or observer change.

Mixing light won't.

Hope this help a bit, there's a lot more theory to understand like the tridimensional space of color, complementary colors, gloss etc...

The really counter intuitive thing about the additive process is that if an object reflects red,blue and green equally we see it as white.

From my high school physics book.

(and I won't tell you how old it is ... but, I'll give you a hint ... Moses used the same book .)

And I thought you are a young man, but a classmate of moses.

BTW : Did moses study physics ? May be for the colours but does not look likely.

Or was it him or him?

The fundamental (or primary colours) may be additive or subtractive.

Thus If you add lights - Red + Blue + Green - you get the white light. These are the additive primaries. Of course there are other combinations possible but these are taken as historically the primaries.

However when we use pigment or paints then say the red pigment is absorbing all the colours except red and similarly for the others (Blue - all except blue, Green all except green etc). In this case, these are selectively absorbing (for subtractive the primaries are RYB) so unlike the previous case when

selective emission of primaries = white

Selective absorption of all primary colours = black

What happens when these are not mixed but atomised so are separate physically ?

Now one drop sends the R to my eye, the second G and the third B. Since the spacing between them is small we can not distinguish between different droplets and see the overall as white (R+G+B), may be a bit greyish since the light intensity is 1/3rd almost.

http://www.konicaminolta.eu/measuring-instruments/color-light-knowledge/the-language-of-light.html

Between some advertising and product plug, this link gives some description of the light side.

First let me apologize for how long this reply will be but your question involves many different disciplines I have had to use over my life. But this specific topic is one that I dealt with repeatedly in my career. So I will block my answer into several groups.

The composition and myth of white light.

White light is not a single frequency of light it is a collection of all of the visible frequencies of light in one. The picture below of white light interacting with a prism comes from a Wikipedia web page.

The slightly yellow tint of the incoming beam at the right implies to me that this is the light of a tungsten filament incandescent light bulb. Strictly speaking then this light is not purely white for a pure white light would have all frequencies at equal intensities. Think of the difference between white audio noise (equal energy per hertz) and pink audio noise (equal energy per octave). This warm light is thus produced by a cool 2800K black body radiator. The higher filament temperature of a halogen quartz lamp produces a color temperature of 3400K. Unfiltered direct sunlight has a color temperature of 5500k. None of these lights have equal energies for their spectrum but all are considered in some circumstances as white light.

Pigments: making color of white light

Getting something illuminated by white light to show some discernible single color requires absorption of light at different intensities for different frequencies. The easiest technique for this is the use of pigments. So pigments subtract from white light the undesired colors while reflecting the desired colors. So white pigment reflect back all equally and a blue pigment reflect back predominantly blue light only of white light. This is why a blue ball in blue light can be hard to discern from a white ball in the same blue light. Also this is why a red ball in blue light can be hard to discern from a black ball in blue light. (One group of pigments does break this method, fluorescent pigments. Fluorescent pigment takes Ultra-violet light outside the visible spectrum region and converts this light to frequencies inside the visible spectrum. This is why fluorescent signs seem brighter than a sign of just that color. They are brighter than that color.)

Perceiving Color: the principles of the eye

Our eyes have two types of receptors in our retinas; cones and rods. The rods are our fastest and most sensitive receptors in the eye but they cannot discern color. The cones are most sensitive to three distinct colors; Red, Green, and Blue (RGB). The yellow on the paint of your number 2 pencil is made by white light having all but the yellow hue being absorbed. Your eye's red and green receptors then get stimulated partly but simultaneously by the yellow light. Your brain then interprets this as a yellow pencil.

Mixing light to perceive colors not there.

Hues such as the yellow of this smiley are created by your monitor by illuminating both red and green pixels. The ratio of these illuminations are set to produce a yellow message into your brain. But if you magnify the image with a lens or steer this "yellow" light into the prism at the top of this paper, one will see that instead of yellow light being produced by your screen, red and green are both being uniquely produced. But if the yellow light reflected from your pencil enters the prism, yellow light will come out of the prism.

Well I hope I didn't loose you there but there is a lot more I could go into. But to make a simplified summation;

Pigments remove colors from white light, the remainder colors get interpreted by your eye's three receptors as a single hue. Mixing light add directly the three receptor colors to mimic a color.

RE: the misty droplet behaves like light instead of pigment:

could this be because of translucency at this droplet size ?