Sir Isaac Newton discovered that if he sent white light through a prism, it separated the white light into a spectrum of colors (ROY G BIV). He then discovered that if he sent the spectrum of colors through another prism white light came out the other side.
White Light Prism Prism White Light
White light is not a single color, but a mixture of many colors of light. A prism separates colors that already exist in white light. It does NOT create colors. Each color (frequency) is refracted at a different angle by the prism.
Since each color has a different frequency, it also has a different wavelength. The longer wavelengths are bent the least and the shorter wavelengths are bent the most.
Think about the track. The outside lane is the longest but has the least curve to it (bent the least). So red, which is on the outside of the rainbow, has the longest wavelength and is refracted (bent) the least. Violet is the shortest wavelength and is refracted (bent) the most.
The Primary Colors of Light RED BLUE GREEN
The primary colors of light are red, blue, and green unlike the primary colors of paint (red, blue and yellow) you learned in elementary school.
Combining the primary colors of light allow us to form new colors called secondary colors.
Shine the red and blue flashlights on the same spot.
Red + Blue = Magenta
Shine the blue and green flashlights on the same spot.
Blue + Green = Cyan
Shine the red and green flashlights on the same spot.
Red + Green = Yellow
Shine the red, blue and green flashlights on the same spot
Red + Blue + Green = White
Red White Light Blue Magenta Yellow Cyan Green
Two colors of light that can be added together to form white light. Complementary colors are the combination of a primary color of light plus a secondary color of light.
Magenta + = White Light Red White Light Blue Magenta Yellow Cyan Green
Magenta + Green = White
Blue + = White Light Red White Light Blue Magenta Yellow Cyan Green
Blue + Yellow = White
Cyan + = White Light Red White Light Blue Magenta Yellow Cyan Green
Cyan + Red = White
Black is not a color but the absence of all colors (light).
Color addition is the mixing of red, blue, and green to form white light. However, paint pigments show colors using a process called color subtraction. This is why the primary colors of paint are different than light.
Color addition is the combining of colors of light to form a new color of light. Color subtraction is the absorption of colors of light to form a new color. If a shirt appears blue in white light it is because the shirt absorbs all the colors that make up the white light EXCEPT the blue light which is reflected back to your eyes for you to see.
Why does a black shirt appear black?
It appears black because it is absorbing all of the colors of light. When that light is absorbed, the light (radiant) energy turns into heat (thermal) energy.
This is why people wear light colored clothes in the summer and dark colors in the winter.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under red flashlight.
Under ideal conditions, the red cardboard would have looked red since only red light was hitting it and red light is reflected back to you to see. Under ideal conditions, the red cardboard would have looked black (the absence of color) under blue and green light since both of those would be absorbed. Under ideal conditions, the red cardboard would have looked red under magenta light since it is made up of red and blue light. The red would be reflected and the blue would be absorbed.
Under ideal conditions, the red cardboard would have appeared red under yellow light since yellow is made of red and green light. The red light is reflected while the green light is absorbed. Under ideal conditions, the red cardboard would have appeared black under cyan light since cyan is made of blue and green light. Both blue and green light are absorbed.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under blue flashlight.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under green flashlight.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under magenta flashlight.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under yellow flashlight.
Show the red, blue, green, magenta, yellow, and cyan pieces of cardboard under cyan flashlight.
Using your data table, what color should a red rose look under green light?
The petals of the red rose reflect only red light and absorb all others. Since only green light is hitting it, there is nothing reflected back to your eyes and it will appear black.
What colors are reflected by a yellow banana?
A yellow banana reflects red and green light and absorbs blue light. Therefore under white light it looks yellow which is the combination of red and green which were present in the white light. Under red light it will appear red since only red light is hitting it. Under blue light it will appear black since blue light is absorbed Under a combination of red and green light it will appear yellow since both of those are reflected and combine to form yellow.
When the color wheel is stationary you see the primary colors of light (red, blue, and green).
When the color wheel is spinning you see white. All the colors that are present blend together forming the white color. White is the combination of all of the colors as it spins.
The strobe light only allows you to see the color wheel only when the light is shining on it. By adjusting the frequency of the flash you were able to make it so that the color wheel appeared to be stationary, rotating in the opposite direction, have 2 red pie shapes, etc.
Have you ever seen this phenomenon before?
If you watch an old movie, the wheels of cars and wagons appear to be turning backwards compared to the direction the car is moving. This is because the film only allows you to see the wheels at specific intervals just like the strobe light only allowed you to see the color wheel at specific intervals.
What would you see if you looked VERY closely at the colors in the Sunday Comics or color ads?
All of the variations of colors you see are made up of tiny dots of just three colors that are present in varying amounts. What colors are those?
Look at the following ads from a Houston newspaper.
Notice how the colors show up as the different layers of film are added.
Just the yellow:
Just the yellow & magenta:
Nearly complete with yellow, magenta & cyan:
Now ready for mailing yellow, magenta & cyan plus black for shading.
Just the yellow:
Just the yellow & magenta:
Nearly complete with yellow, magenta & cyan:
Now ready for mailing yellow, magenta & cyan plus some black for shading.
The secondary colors of magenta, cyan, and yellow are used in color printing. The color black is also used to give definition, depth and contrast.
The cost of the ad increases as more color plates are needed. Typically, garage sale ads are done in black and white only because it is the cheapest. During the week, car dealerships may run a two color ad. On weekends when there is a larger readership, more business buy 4 color ads.
Have you ever seen the comics when they look blurry and things don t quite line up? What causes it?
This happens when the color plates that are used to make the comics are not quite aligned.
The human eye has cone cells for detecting red, blue, and green light. These cells are used for daylight vision. Rod cells are used in night vision since they detect only light and dark.
Stare at the center of the circle in the next slide.
Cyan is composed of blue and green. After staring at cyan for a long time, you have exhausted the blue and green cone cells in your eye. Therefore, you see red after staring at cyan.
When have you ever experienced this phenomenon?
When someone takes your picture using a flashbulb, you see black spots. The flashbulb exhausted all of the cone cells in your eye so none of them were working for a few moments.
Stare at the center of the circle in the next slide.
Yellow is composed of red and green. After staring at yellow for a long time, you have exhausted the red and green cone cells in your eyes. Therefore, you see blue after staring at yellow.
Stare at the center of the circle in the next slide.
Magenta is composed of red and blue. After staring at magenta for a long time, you have exhausted the red and blue cone cells. Therefore, you see green after staring at magenta.
Your eyes are capable of more complicated shapes than circles. Stare at the center of the heart on the next slide.
You should have seen a red heart after staring at the cyan heart since you have exhausted the green and blue cone cells from staring at cyan.
Stare at the center of the next slide.
You should have seen a green smiley face since your blue and red cone cells were exhausted from staring at the magenta smiley face.
Your eyes are capable of resolving an even more complicated picture. Stare at the center of the next slide.
Your eyes are capable of resolving an even more complicated picture. Stare at the center of the next slide.
The U.S. flag was originally cyan, yellow and black. After it was removed it appeared red, white, and blue.
Stare at the center of the even more complicated picture.
Color blindness usually involves the colors of red and green. Color blindness is found in 4% of the male population and 0.25% of the female population.
Color blindness is a sex linked recessive genetic trait that appears on the X chromosome. Since men have only one X chromosome, if the gene for color blindness appears on it, they will be color blind. Women have two X chromosomes and it would have to appear on both X chromosomes before the woman would exhibit the trait.
What do you see in the next slide?
Everyone should have seen the number 25.
What do you see in the next slide?
If you have normal vision you should see the number 29. If you are red-green color blind you will probably only see spots.
What do you see in the next slide?
If you have normal vision you should see the number 45. If you are red-green color blind you will probably only see spots.
What do you see in the next slide?
Everyone should see the number 56.
What do you see in the next slide?
If you have normal vision you should see the number 6. If you are red - green color blind you will probably only see spots.
What do you see in the next slide?
If you have normal vision you should see the number 8. If you are red - green color blind you will probably only see spots.
What NUMBER do you see in the next slide?
The individual with normal color vision will see a 5 revealed in the dot pattern. An individual with red - green (the most common) color blindness will see a 2 revealed in the dots.
Can you find the old woman and the young girl?
The old woman is facing the left and wearing a fur coat. The young woman is facing the back and wearing a necklace.
Can you find the rabbit and the duck?
The duck is facing the left and the rabbit is facing the right.
How many tines are there?
Notice what looks like a tine one the left turns into empty space at the right.
What makes up the front of the crate?
Notice how what is an inside piece on the bottom right turns into an outside piece on the bottom left.
Are the two lines equal in length?
YES they are the same length. They appear different lengths because of the arrow heads connected to them.
What do you see?
You should see the word LIAR written in cursive and a person s face.
Stare at the red parrot for 20 seconds. Then look at the bird cage. You should be able to see the image of a cyan bird in the cage. Then stare at the green parrot for 20 seconds. Then look at the bird cage. You should now see a magenta bird in the cage.
What do you see?
There is an Eskimo turned away from you or an Indian facing left.
Each different picture represents the change of just one line and it transforms the face into a woman kneeling and facing the right side.
What do you see?
You should be able to see a woman s face or a person playing a saxophone.
What do you see?
How many faces do you see?
There are three faces there. Two are facing each other and the third is facing forward.
How many legs does the elephant have?
Some of what appear to be feet at the bottom of the diagram turn into space at the top and what appears to be legs leaving the body turn into free space at the bottom.
What do you see in the picture?
You should be able to see a woman looking in a vanity mirror or a skull.
What do you see?
You should be able to see a vase or two people facing each other.
How many people can you see?
There are 9 people in the picture.
What color are the horsemen?
There are off white horsemen moving to the left and brown horsemen moving to the left.
What do you see?
Do you see the man or woman? Or do you see both? Or are there THREE people in this picture. If you are missing it, the man is the brown moustache. The woman is looking to the left and you can see here eye and nose protrude from the left part of the image. There is also another face - the woman's chin is the nose for this third face, and the wrinkle in the womans neck is the mouth.
Do you see concentric circles or a spiral?
This is another great example of concentric circles that look like a spiral. The red and black diamonds further add to the illusion, and even give the illusion some depth, because they are drawn in perspective, with the center as the vanishing point. This type of perspective is called one-point perspective and involves two sides of each object pointing to the same spot on the page. This is one of my favorite optical illusions!
What do you see?
A polar bear crawling out of a hole in the ice and a seal laying on the ice facing to the left!
How many columns are there?
Are the black lines parallel?
Parallel
Which do you see?
If you look at the picture upright you should see a crane holding a baby in its mouth or if you look at the picture upside down you should see a fish with a canoe in its mouth
What do you see?
a skull or two circus performers holding hands
How many faces do you see?
There are at least 20
What do you see?
an old man or two lovers kissing
What do you see?
Did you find the Dalmation?
What do you see?
the old woman or the young girl
Which do you see?
the two faces or the vase
What shapes are drawn?
Did you include white triangles? They weren t drawn, but our minds fill them in due to the gaps in the other shapes.
Who is up and who is down?
Which way are the birds flying?
Is it really moving?
Is the water flowing up hill or down hill?
Is the book open towards you or away from you?
What do you see at the intersections of the lines?
What do you see?
Sailboards or fish
How many people do you see?
At least 5
What do you see?
Do you see the baby? His feet are on the right side outlined by the branches and the trunk of the tree.
How many shades of green?
There is only one shade of green shown. It looks different due to the colors surrounding it.
What do you see?
Snow covered ground or horses