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Color in pigment and light (Read 2092 times)
Nov 11th, 2009 at 8:28am

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To forum readers:
This is an email talking about light and pigments between Robin and I.
You have to start from the bottom, and go to the top of each post as you work your way up. I'm sorry but that's the way my email comes to me. I answer from the top.
(-) Robin
(~) Don

On Nov 10, 2009, at 7:02 PM, Don Jusko wrote:
~Hi Robin,
Scroll down for more on reflection and absorption of color.
Don

On Nov 10, 2009, at 6:18 PM, Robin S wrote:
-Wow Don,
This is really deep.
thank you so much for taking the time to talk about this. You are evidently passionate about it, and I am most interested to understand it better.
I do agree that I am confusing light and pigment, and I do understand the difference.
My problem is that I see the two having to be intertwined and I don't know how to separate the two.
~Let me go a step farther.
Emitted light, from a computer, a candle or the sun. Makes a light wave.
Reflected light from an object is dead, it can't be seen in the dark.
- Light, is what bounces back at us, FROM the surface of the object...or item painted/colored with the pigments...thus...LIGHT is how we see the color of the pigment, by the reflected light back at our eye.
So, how do the two stay separate. we need the LIGHT to come off the object so we can see the color of the pigment...which is really just reflecting, refracting, absorbing
~ Never "absorbing light", the internet and a lot of books are wrong about that. Light has energy, that energy will be absorbed by a dark object, not the color.. the heat energy. Refracting requires a transparent object. You should not toss around terms that don't apply. Reflecting is 100% from a mirrored object and a much lower % from a matte object. A dark object will absorb the lights heat energy, not color.

- ..light rays.
I understand the additive vs.. subtractive, and how white light is the presences of the whole spectrum..but if that is the case...then WHAT kind of light rays are we seeing when we see magenta object..magenta paint.....what is it composed of...
I love the "pigment our our imagination"...and magenta is my main bug a boo..I just don't know why in some cases is is composed of blue and red.. (as it does appear cool)
~Magenta is composed of red and blue light. Magenta pigment is pretty hot next to blue.
- but in pigment , it can be anything but that. I mean..What makes magenta...and how does it stay clean so it does not muddy up a pigment mix...as in adding three primaries together would.
(in particular, adding magenta , which is cool and has the look of having blue in it...plus yellow to get red.)
~ Magenta is not cool, it's cooler than yellow and warmer than yellow's opposite color, blue. Magenta is a medium temperature just like green. The line between them divides the warm and cool.
- double yikes..., and I driving you crazy? I am sorry if I am slow to get this totally.
~ I hope the difference between emitted and reflected is clear to you now, and I hope you pass this information along.
Robin

-----Original Message-----
From: Don Jusko
Sent: Tuesday, November 10, 2009 5:45 AM
To: Robin S
Cc: Don Jusko
Subject: Re: More about color magenta, Robin, Don2
On Nov 9, 2009, at 5:15 PM, Robin S wrote:
Hello Don,
~Hi Robin,
The subtractive colors (pigment) subtract light, red and blue mix to a very dark dark, subtracting value.
Additive colors (light) do the opposite, all colors making white.
- Thank you for the detailed explaination.
I think I understand it.
But another question.
Would it be fair to say then, that magenta is a combination of the blue and red light? (as in the prism experiment)
but actually is that a additive processs then?
So, how do we explain how the traditional Red on the color wheel, is really not the correct primary, as magenta should be, but magenta then is made up of red and blue if that were the case?
~ Don't confuse the light color wheel with the pigment color wheel. The two will never meet.
It's easy to mix red and blue light (additive) and get cyan light
It's also easy to mix cyan and magenta to get blue pigment (subtractive).

-I did some paint mixing with WC magenta. (opera)
~Good choice
-mixed with hansa yellow..
~fairly good choice, transparent yellow would have been better. The translucent hansa does have some opaque qualities which dulled the red a little too much to get a very good red.

-if Magenta had blue in it,
~"Magenta has blue in it" only in the additive light color wheel. It has no cyan or blue in it in the pigment world.
-then how could I mix a clean red?
- The Nickel element (transparent yellow) mixed with PV19 (a warm magenta) or Opera PR122+10Q makes bright reds.

- If it is a pigment of our imagination,
~ That was my joke, I shouldn't have tried to be funny, it's not my nature.
- but it is diffraction of a wave length, that is an overlap? (is this correct) of blue and red?
~ DIFFRACTION; the process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced.
~ DIFFRACTION, diffraction is light bending around the edges of a mass.
~ REFRACTION; The deviation of a ray of light upon entering a transparent medium is refraction away from the normal. The emerging ray is separated into the colors of the spectrum. Red refracts most, violet and magenta the least.
~ DOUBLE REFRACTION, an incident ray enters and splits, each ray traveling at a different speed.
~ DISPERSION, Diamonds, glass and water give dispersion of light with the proper incident and reflecting angles, thus splitting up white light into its spectrum colors.
- pleochroism in minerals is due to adsorption (- should be reflectance not absorption) of particular wavelengths of light.
~ PLEOCHROISM, the change of color in a crystal when viewed from different directions.
Wikipedia is right.
Pleochroism is an optical phenomenon in which mineral grains within a rock appear to be different colors when observed at different angles ...
en.wikipedia.org/wiki/Pleochroism

Webmineral is wrong about mineral absorbing wavelengths saying:
The primary cause of dichroism or pleochroism in minerals is due to adsorption of particular wavelengths of light. This selective adsorption of certain ...
webmineral.com/help/Pleochroism.shtml
webmineral is right here though,
http://webmineral.com/help/RLPleochroism.shtml

INTERFERENCE COLORS, a thin film of soap or oil will change the direction of the incident ray laterally and cause the prism effect, as the thickness changes the color's change.

- Are you asking if an oil slick is additive or subtractive? Good question, it makes me think.
All colors are seen in an oil slick and they are all interference colors. Blot the oil slick on a white blotter and you would see no color.
~ So we are seeing additive colors not pigment colors.

-I belive I see it in many things, but then how is it REd shows up in rainbows, prisms, etc, but it then is not the true primary? if red is made up of blue and red light, then wouldnt the actual red still be a better choice as primary..yet magenta is the better mixer...
~Your confusing light with pigments.

-I am still confused obvioulsy, when it comes to how can it be seen as pigment, and work as a subtractive color mixing agent, but it is not next to red either? If it has the longest wavelenght,,,then it does not lie on the spectrum  next to the shortest, red...or does it?  I guess I am not really sure how we found it to work as a pigment.?

~I've always thought of the colorwheel as a circle, in a rainbow the circle is a tube, magenta is at the back of the tube.
Also, in light black is clear.

-Yikes...
yikes..
Robin
Don

-----Original Message-----
From: Don Jusko [mailto:donjusko@realcolorwheel.com]
Sent: Friday, November 06, 2009 4:07 PM
To: Robin S
Cc: Don Jusko
Subject: Re: question about color magenta, Robin, Don

On Nov 6, 2009, at 6:09 AM, Robin S wrote:
Hi DOn,
I am confused.
I understand how magenta is the truere color to use for the primary.
But, how is it that it is invisble in the light spectrum, but we can see it as pigment color. How can this be?
What light waves are we seeing when we "see " the color magenta then? And how can it be a component of the reds ect if it is invisible to our eye as light, but we can see it as pigment?
HELP...I am totally lost now, and I thought I had it. but you are right, it does not show up in a rainbow...
but then, it is in lets say a rainbow of oil slick......

~Hi Robin,
It is commonly thought the color magenta can not be seen in the prism, but this is not true, it depends on the viewing angle of the prism while you are looking into it.
It's also thought that magenta can't be seen in a rainbow but I have seen bright rainbows with magenta at the bottom of it.
The invisible wavelengths of magenta in the EM spectrum can be read and will turn a switch on an off.
http://www.realcolorwheel.com/rainbow.htm
http://www.realcolorwheel.com/final.htm#RAINBOWS_AND_SPECTROSCOPES

You are thinking that just because magenta can't be seen in the EM spectrum it can't be seen in light but it can.
DIFFRACTION is a light ray angling around a solid object. Diffraction also is the only way to see the atmospheric light color magenta in it's pure state.
Diffraction is what happens to a ray at it's light stopping edge, stopped by an opaque object, it bends. The longest wavelength color can/will make the greatest diffracted angle. Magenta waves are still angling out of the straight white light that has already passed the stopping edge of the earth. They are moving in the shadow area on there way to a principal focusing point on the center line's axis, deep in the heart of the earths shadow. Red and orange diffract a little and magenta, the shortest wave, bends the most around an object. There is some warm magenta on the outside of red on a strong rainbow and on inside of the second rainbow, and is the last color seen before the dark of night. This is color diffracting, in real time, focusing on a focusing point inside the shadow's void behind the earth, where the center of diffraction for that ray of light is bending toward.
May I suggest a simple experiment that you might find informative?
At a time when sunlight shines directly into a window, place a prism in the sunbeam and adjust it so that it casts a rainbow spectrum onto something white that is not in the sunbeam.
Notice that magenta isn't there. (But you knew that.) Now place a second prism so that its projected rainbow crosses the first one. At each place where the red end of either spectrum crosses the blue end of the other you will see a magenta patch.
Try as you might, you won't find a wavelength for magenta. It is a psychological color, produced in your mind when the eye receives blue and red light in the same area.
It is not bending the meaning of words too sharply to say that magenta is a pigment of your imagination.

The EM spectrum has wavelengths in a line, red and blue at the two ends, they never overlap to see the color magenta. In an oil slick the the prism is distorted and merges to show the magenta color.

- Can you explan this better to me?
thanks so much
Robin

-----Original Message-----
From: Don Jusko [mailto:donjusko@realcolorwheel.com]
Sent: Thursday, November 05, 2009 3:43 PM
To: Robin S
Cc: Don Jusko
Subject: Re: freePenPalettes-tiffromcolorwheel, Robin, Don


On Nov 5, 2009, at 7:44 AM, Robin S wrote:
thank you
-Robin
(THIS IS THE START OF DON'S AND ROBIN'S CONVERSATION)
~Hi Robin,
http://www.wikihow.com/Use-the-Real-Color-Wheel
BACKGROUND INFORMATION:
I first notice that magenta seems to slide into the yellow and cyan areas of color, taking more than its 1/3rd share of the wheel as the colors get darker. I noticed the phenomenon at sunset, because the magenta light rays are longer they bend around the earth giving a red sky at night. I noticed a similar color change in the physical elements making crystals. Darker cyan turns to ultramarine blue by adding magenta like in the polarizing Iceland Spar crystal and yellow adds red (magenta) in most all yellow crystals, iron being the most common. Iron oxide makes colors from Amberg yellow ocher to raw umber, heating the raw umber to burnt umber brings out even more red. It's a natural phenomenon in the physical colorwheel.
 
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