Our senses don t deceive us; our judgment does. Johann Wolfgang von Goethe

Transcription

1 Our senses don t deceive us; our judgment does. Johann Wolfgang von Goethe 1

2 ULTRAVIOLET X-RAYS GAMMA RAYS VISIBLE MICROWAVES SPECTRUM INFRARED RADIO WAVES VIOLET BLUE CYAN GREEN YELLOW RED MAGENTA The visible spectrum The part of the electro-magnetic spectrum that we can see contains millions of colors of varying wavelength. Light from the sun contains all of these colors. A prism splits these colors into the familiar rainbow. 2

3 The eye has receptors sensitive to the primary colors red, green and blue. Stare at the dot in the middle of the red square for 30 seconds, then shift quickly and stare at the dot in the white square.what color do you see? Red stays on the retina as an after-image of its complementary color, cyan blue. 3

4 Now stare at the dot in the middle of the white star for 30 seconds, then shift to the dot in the white square.what do you see? This after-image is due to the rods and cones in the eye becoming sensitized.the after-image is responsible for many phenomena we take for granted, such as motion pictures and the color reproduced on a computer screen or printed page. 4

5 Additive color The receptors in the eye are sensitive to the primary colors red, green and blue.these are called the additive primaries, or projected color primaries. 5

6 BLUE Additive primaries (red, green and blue) are used to reproduce color on a TV screen, in color film and on a computer screen.

7 GREEN BLUE Red, green and blue (RGB) are called additive primaries because as each color is added to a black screen, they blend to form lighter colors.

8 YELLOW RED GREEN MAGENTA CYAN BLUE Where RGB overlap, complementary colors form.when we stared at the red square, we developed an after-image.when we switched to the white square, we saw that after-image as cyan, the complementary of red.

9 Projected color With additive color, the three primaries of red, green and blue are projected one on top of the other to form a composite image. Note that where all three colors are present, such as the bride s veil, the result is white.

10 Subtractive color The complementary colors to red, green and blue form the subtractive primaries of cyan, magenta and yellow.these subtractive primaries are used in printing, along with black, in what is known as the four-color process.the shorthand for this is CMYK, with K standing for black.

11 Subtractive color sometimes is called reflected color because it is used in printing, where the ink on the page absorbs colors of some wavelengths and reflects others. Remember that in additive color, as we add more and more of the primaries of red, green and blue, we approach white.with subtractive color, it s the other way. 11

12 With subtractive color, as we subtract color, we get closer to the white of the page.where no ink is present, we see white, or as close to white as the paper gets. Because the paper is never pure white, and because the inks are never pure cyan, magenta and yellow, the colors can look dull without black to add shadow and detail. 12

13 Separation Before a color picture can be printed, it must be separated into it the four colors.this was done with a camera using filters.today pictures are separated by scanners. These devices separate a color picture into either RGB or CMYK and store the information as digital computer files. Note that with this separation, the white of the veil is produced by an absence of ink in any of the four colors. 13

14 With subtractive color, black is added to the primaries of cyan, magenta and yellow to provide depth, especially in the shadow areas. Because of impurities in the ink, mixing cyan, magenta and yellow will not produce a true black, only a dark gray.the top photo has no black undercolor.the bottom photo does; its black undercolor is displayed below. 14

15 The colors in either additive or subtractive color are not mixed but rather presented individually.the eye does the mixing in a technique similar to that used by French artist George Seurat. In his painting Sunday Afternoon on the Island of the Grande Jatte he portrayed the play of light using tiny brushstrokes of contrasting colors.the style became known as pointillism. Using this technique, he created huge compositions with tiny, detached strokes of pure color too small to be distinguished when looking at the entire work but making his paintings shimmer with brilliance. 15

16 Here is another Seurat painting, The Side Show. The detail to the right shows how pointillism worked. Seurat used precise formulas for how much of each pure color to use to produce the desired overall color. 16

17 Other artists have used similar techniques, believing that the colors seen by the eye appear more pure and vibrant than those created by mixing ink. Paul Klee used a mosaic technique (above), while Chuck Close uses small squares, each a tiny abstract painting, to produce an overall image. 17

18 18 Four-color printing On a printed page, color is produced in much the same way as Seurat did it, with tiny dots of color. After a picture is separated into cyan, magenta, yellow and black, each of those images is converted to a halftone.when the halftones are printed on top of another, they form rosettes of colors.the eye mixes these into millions of realistic colors.the dots in the halftones line up at varying angles to prevent them from being printed on top of each other.

19 19 Registration When the cyan, magenta, yellow and black plates go through the printing press, they must line up exactly, or the picture will appear muddy or 3D-like, such as the picture to the left.the mark of fine printing is color that is in perfect registration. The picture to the left is one that is out of register.

20 20 Color measured in percent The halftone is able to produce millions of colors by varying the size of the dots in each of the four colors (CMYK). Notice how the dots in the detail above vary in size, sometimes approaching complete coverage (100%) and at other times dwindling to almost no coverage (0%).The amount of CMYK color is expressed in percent for each of the four colors.

21 21 Flat color Publications use color for text, backgrounds, rules and illustrations, in addition to photos.this advertisement uses color for all these purposes. While the color in a photograph will vary subtly even where it looks uniform, flat color is uniform.the designer calls for a specific color of a specific percentage.that color may be produced by using process color (CMYK) or by using spot color. With spot color, one or two inks from hundreds of colors available are added to the design along with black ink.

22 Color look-up charts For a specific flat color using CMYK, designers turn to color lookup charts, one of which is reproduced here. A chart is made up of small color squares with varying percentages of cyan, magenta and yellow. Sometimes black is added.this chart starts with 30 percent yellow in the upper-left corner. Progressively darker percents of cyan and magenta are added to each square.the next chart would start with a different percent of yellow, say 40 percent, and the process would be repeated. Color lookup charts are printed on coated or uncoated paper, often on the press used for that publication.

23 Pantone and DIC color Several companies offer color guides similar to the color chips found in paint stores.these include Pantone Color Matching and DIC, a Japanese company.the designer uses color guides to specify a spot or process color by number. Pantone is widely accepted by printers in the United States.The color guides are available for coated and uncoated papers, and for spot and process applications. The Ford 021C This concept car was developed for Ford by a fashion designer. Besides its many innovative feature, the 021C is named after its Pantone color. 23 Pantone color guides DIC color guides Pantone 021 CVU (uncoated paper) Pantone 021 CVU converted to process color: 61% magenta 80% yellow DIC 2527p

24 The color palette Designers never work with an unlimited number of colors. Instead they build a palette of the colors that they hope will come to be identified with the publication or product. In advertising, the color palette is extremely important because it becomes tied so closely with product identification.the colors of a designer s palette are chosen for their personality and for how well they work together. 24

25 Color palette and identity Designers are advised to choose their color palettes carefully, then use those colors consistently. Color is so closely tied to identity that a company such as IBM can come to be known as Big Blue. The yellow square around the National Geographic cover has become a trademark all by itself. The best color palettes have meaning beyond consistency.these palettes are chosen for mood, to convey meaning. Often the colors come from the environment; the Boca Raton News is famous for using the tropical colors of Florida. Choose your color palette carefully! 25