The colors in the rgb palette are formed by. Color palettes in RGB, CMYK and HSB color rendering systems. What is a color model

1. In what color rendering system is the color palette formed by adding red, green and blue flowers? 1) HSB 2) RGB 3) WBRK 4) CMYK

2. In what color rendering system is the color palette formed by superimposing cyan, yellow, magenta and black paints? 1) HSB 2) RGB 3) WBRK 4) CMYK

3. How much information (in kilobytes) is contained in a screen picture with a resolution of 512 × 768 pixels and 16 colors? 16= 2 i , i = 4, I = 512768 4 = 1572864 bits / 8 = 196608 bytes / 1024 = 192 KB.

4. How much information (in kilobytes) is contained in a screen picture with a resolution of 256 × 1280 pixels and 256 colors? 256= 2 i , i = 8, I = 256 1280 8 = 2621440 bits / 8 = 327680 bytes / 1024 = 320 KB.

5. To store a bitmap image with a size of 64 × 128 pixels, 8 kilobytes of memory were allocated. What is the maximum possible number of colors in an image's palette? 8 KB = 8 * 1024 = 8192 bytes * 8 = 65536 bits 64*128 = 8192 65536 / 8192 = 8 bits per dot 28 = 256 Answer: 256 colors.

6. To store a bitmap image of 128 × 256 pixels, 4 kilobytes of memory were allocated. What is the maximum possible number of colors in an image's palette? 4 KB = 4 * 1024 = 4096 bytes * 8 = 32768 bits 256*128 = 32768 /32768 = 1 bit per dot 21 = 2 Answer: 2 colors.

7. Bitmap file containing black and white drawing, has a volume of 1.5 kilobytes. What is the size of the image in pixels? 1.5 KB = 1.5*1024 = 1536 bytes *8 = 12288 bits 2= 2 i , i = 1 bit (black and white picture) 12288/1= 12288 pixels.

Number of dots over the entire horizon vertical or vertical Number of information color bits per screen point 800 600 480000 256 8 3840000 bits 640 480 307200 2 1 320 200 102400 16 4 307200 bits 409600 bits

White light can be decomposed using optical instruments (such as prisms) or natural phenomena (rainbow) into various colors spectrum: red, orange, yellow, green, cyan, indigo and violet.

A well-known phrase that makes it easy to remember the sequence of colors in the spectrum of visible light: every hunter wants to know where the pheasant is sitting.

Rice. 3.7.

A person perceives light with the help of color receptors (so-called cones) located on the retina. Cones are most sensitive to red, green, and Blue colour a, which are basic to human perception. The sum of red, green and blue colors is perceived by a person as white, their absence - as black, and their various combinations - as numerous shades of colors.

The color palette in the RGB color rendering system. From the monitor screen, a person perceives color as the sum of the radiation of three basic colors: red, green and blue. This color rendering system is called RGB, after the first letters of the English color names (Red - red, Green - green, Blue - blue).

Colors in the RGB palette are formed by adding base colors, each of which can have different intensities. The color of the Color palette can be determined using formula (3.3):

At the minimum intensities of all basic colors, a black color is obtained, at maximum intensities, a white color is obtained. At the maximum intensity of one color and the minimum of the other two - red, green and blue. The superposition of green and blue forms cyan (Cyan), the superimposition of red and green - yellow(Yellow), red and blue overlay - magenta (Magenta).

Table 3.4

Shaping colors in the RGB color rendering system

In the RGB color rendering system, the color palette is formed by adding red, green, and blue colors.

With a color depth of 24 bits, 8 bits are allocated for encoding each of the primary colors. In this case, N = 2 8 = 256 intensity levels are possible for each of the colors. The intensity levels are set in decimal (from the minimum - 0 to the maximum - 255) or binary (from 00000000 to 11111111) codes (Table 3.5).

Table 3.5

Color encoding at 24-bit color depth

Color palette in CMYK color rendering system. When printing images on printers, a palette of colors in the CMY system is used. The main colors in it are Cyan - blue, Magenta - purple and Yellow - yellow.

Colors in the CMY palette are formed by overlaying inks of base colors. The color of the Color palette can be determined using formula (3.4), in which the intensity of each paint is given as a percentage:

A person perceives an image printed on paper in reflected color. If no paint is applied to the paper, then the incident white light is completely reflected and we see a white sheet of paper. If paints are applied, they absorb certain colors. Colors in the CMYK palette are formed by subtracting certain colors from white.

When applied to paper, blue ink absorbs red and reflects green and blue light, and we see blue. When applied to paper, magenta ink absorbs green and reflects red and blue light, and we see magenta. When applied to paper, yellow ink absorbs blue and reflects red and green light, and we see yellow.

By mixing two colors, we get the base colors in the RGB color rendering system. If magenta and yellow are applied to paper, green and blue light will be absorbed and we will see red. If blue and yellow paints are applied to paper, then red and blue light will be absorbed and we will see green color. If magenta and cyan are applied to paper, green and red light will be absorbed and we will see blue color.

Rice. 3.8.

Mixing three colors - cyan, yellow and magenta - should lead to complete absorption of light, and we should see black. However, in practice, instead of black, a dirty brown color is obtained. Therefore, another, true black color is added to the color model. Since the letter B is already used to designate blue, the last letter in the English name for black is Black, i.e. K. The extended palette is called CMYK.

Table 3.6

Shaping colors in the CMYK color rendering system

In the CMYK color rendering system, a palette of colors is formed by superimposing cyan, magenta, yellow, and black inks.

The RGB color rendering system is used in computer monitors, televisions and other technical devices that emit light.

The CMYK color rendering system is used in printing, as printed documents are perceived by a person in reflected light. In inkjet printers for imaging High Quality Uses four cartridges containing CMYK base inks.

Rice. 3.9.

The color palette in the HSB color rendering system. The HSB color rendering system uses Hue (Color hue), Saturation (Saturation) and Brightness (Brightness) as basic parameters. The Hue parameter allows you to select a color hue from all colors of the optical spectrum, from red to violet (H = 0 - red, H = 120 - green, H = 240 - blue, H = 360 - purple). The Saturation parameter determines the percentage of "pure" hue and white (S = 0% - white, S = 100% - "pure" hue). The Brightness parameter determines the intensity of the colors (the minimum value of B = 0 corresponds to black, the maximum value of B = 100 corresponds to the maximum brightness of the selected color shade).

In the HSB color rendering system, the color palette is formed by setting the values of a color's hue, saturation, and lightness.

In graphic editors, it is usually possible to switch from one rendering model to another. This can be done both with the mouse, by moving the pointer over the color field, or by entering color model parameters from the keyboard into the corresponding text fields.

PANTONE® Color Guides. Color display depends on many factors. The color rendering methods of a monitor (RGB color rendering system) and paper (CMYK color rendering system) cannot be exactly the same. In turn, the color rendition of different monitors may vary significantly from each other, and the color rendition also varies when printed on various types paper.

The de facto standard for color identification is Pantone's color guides. Pantone is a developer and manufacturer of technology solutions for color selection and accurate color communication. For more than 40 years, the Pantone name has been known throughout the world as a universal color language for communication between customers, designers and manufacturers of printing, textile and other products. Color identification extends not only to images displayed on paper, but also to the screen. Pantone guides are a set of sheets with test printing indicating the numerical values of the color in the RGB or CMYK system.

Exist various options guides with samples of printing on plain, coated, glossy or matte paper.

When preparing an image for printing on inexpensive mass-produced monitors, colors will be distorted. Using the reference book, you need to specify the desired color values. Printed colors must match the colors in the reference book.

Rice. 3.10.

Having color guides, you can calibrate the monitor. It is necessary to draw rectangles in the layout program, painting them with colors according to the color guide, and then, using monitor adjustments or choosing different profiles in the layout program, try to match the colors on the screen to the color of the guide. Almost all modern video cards come with drivers that allow you to adjust the color rendering.

Naturally, such a calibration will be quite approximate. For the correct calibration of the monitor, scanner and printer, special devices are used - calibrators. Calibrators are installed in front of the monitor screen and connected to a computer using a USB port.

Control questions

1. In what natural phenomena and physical experiments can one observe the decomposition of white light into a spectrum?
2. How is the color palette formed in the RGB color rendering system? In the CMYK color rendering system? In the HSB color rendering system?
3. What are PANTONE color guides for?
4. Why are calibrators needed?

Tasks for self-fulfillment

3.8. Short answer question. Detect colors if base color intensities are specified in the RGB rendering system. Fill in the table.

3.9. Short answer question. Detect colors if the paper is inked in the CMYK color rendering system. Fill in the table.

	Color shaping
	C=0, M=0, Y=0

A person perceives light with the help of color receptors (so-called cones) located on the retina. The cones are most sensitive to red, green, and blue, which are the basic colors for human perception. The sum of red, green and blue colors is perceived by a person as white, their absence - as black, and their various combinations - as numerous shades of colors.

From the monitor screen, a person perceives color as the sum of the radiation of three basic colors: red, green and blue. This color rendering system is called RGB, after the first letters of the English color names (Red - red, Green - green, Blue - blue). Colors in the RGB palette are formed by adding base colors, each of which can have different intensities. The color of a Color palette can be determined using a formula.

Color = R + G + B, where 0

With a color depth of 24 bits, 8 bits are allocated for encoding each of the primary colors. In this case, N = 2 8 = 256 intensity levels are possible for each of the colors. Intensity levels are given by codes: - decimal (from minimum - 0 to maximum - 255); –Binary (from to)

Color coding at 24-bit color depth Color Binary and decimal coding of primary color intensity Red GreenBlue Black Red Green Blue Cyan Magenta Yellow White

When printing images on printers, a palette of colors in the CMYK system is used. The main colors in it are Cyan - blue, Magenta - purple and Yellow - yellow. The CMYK system, unlike RGB, is based on the perception of not emitted color, but reflected light. A person perceives an image printed on paper in reflected light. If no paint is applied to the paper, then the incident light is completely reflected, and we see a white sheet of paper. If the paint is applied, then they absorb certain colors. Colors in the CMYK palette are formed by subtracting certain colors from white.

Cyan = W - R = G + B When applied to paper, cyan ink absorbs red light and reflects green and blue light, and we see cyan. Cyan = W - R = G + B Magenta = W - G = R + B When applied to paper, magenta ink absorbs green light and reflects red and blue light and we see magenta. Magenta = W - G = R + B Yellow = W - B = R + G When applied to paper, yellow ink absorbs blue light and reflects red and green light, and we see yellow. Yellow \u003d W - B \u003d R + G Red \u003d Y + M \u003d W - R - B If magenta and yellow are applied to paper, green and blue will be absorbed, and we will see red. Red \u003d Y + M \u003d W - R - B Green \u003d Y + C \u003d W - R - B If you put blue and yellow paint on paper, then red and blue will be absorbed, and we will see green. Green \u003d Y + C \u003d W - R - B If purple and cyan are applied to paper, then green and red will be absorbed, and we will see blue. Blue \u003d M + C \u003d W - R - G

Color formation in the CMUK color rendering system Color Formation of color Black Black = C + M + Y = W - G - B - R White White = (C = 0, M = 0, Y = 0) Red Red = Y + M = W - R - B Green Green = Y + C = W - R - B Blue Blue = M + C = W - R - G Cyan Cyan = W - R = G + B Magenta = W - G = R + B Yellow Yellow = W - B \u003d R + G

Mixing three colors - cyan, yellow and magenta should lead to complete absorption of light, and we should see black. However, in practice, instead of black, a dirty brown color is obtained. Therefore, in the color model there is one more, true black color. Since the letter "B" is already used to designate blue, the last letter in the English name for black "Black" has been adopted to designate black, i.e. "K" In the CMYK color rendering system, the color palette is formed by superimposing cyan, magenta, yellow, and black inks.

CMYK model The CMYK model is subtractive; to obtain a new shade, you need to remove the primary colors in certain proportions. Cyan = White - Red = Green + Blue Magenta = White - Green = Red + Blue Yellow = White - Blue = Red + Green Black White + Red + Green + Blue

The RGB color rendering system is used in computer monitors, televisions and other technical devices that emit light. The CMYK color rendering system is used in printing, because printed documents are perceived by a person in reflected light. Inkjet printers use four primary color cartridges to produce high quality images.

The HSB color rendering system uses Hue, Saturation, and Brightness as basic parameters. The Hue parameter allows you to select a color hue from all colors in the optical spectrum, from red to violet (H = 0 - red, H = green, H = 240 - blue, H = 360 - violet). The Saturation parameter determines the percentage of "pure" hue and white (S = 0% - white, S = 100% - "pure tint"). The Brightness parameter determines the intensity of the color (the minimum value B = 0 corresponds to black, the maximum value B = 100 corresponds to the maximum brightness of the selected color).

HSB model The HSB model is tuned to human perception of color. In it, all the primary colors are located on top, decreasing in brightness down. For more exact definition desired hue, the gradation bar on the right is used to make the selected color brighter or darker. There is also a choice of color by name and its coordinates translated into the RGB or CMYK model.

Chapter Textbook: Ugrinovich N.D. Informatics and ICT. Basic course: Textbook for grade 9. - 4th ed. –M.: BINOM. Knowledge Lab

slide 2

White light can be decomposed using optical instruments (for example, a prism) or natural phenomena (rainbow) into different colors of the spectrum: red, orange, yellow, green, blue, blue and violet. A well-known phrase that helps to easily remember the sequence of colors in the spectrum of visible light: "Every hunter wants to know where the pheasant is sitting."

slide 3

A person perceives light with the help of color receptors, the so-called cones, located on the retina of the eye. The cones are most sensitive to red, green, and blue, which are the basic colors for human perception. The sum of red, green and blue colors is perceived by a person as white, their absence - as black, and their various combinations - as numerous shades of colors. The rainbow has 7 colors. The eye distinguishes 3 colors. 100 gradations per color.

slide 4

The color palette in the RGB color rendering system.

slide 5

Shaping colors in the RGB color rendering system

At the minimum intensities of all basic colors, a black color is obtained; at the maximum intensity, a white color is obtained. At the maximum intensity of one color and the minimum of the other two - red, green and blue. The superposition of green and blue colors forms cyan (Cyan), the superposition of red and green colors - yellow (Yellow), the superimposition of red and blue colors - magenta (Magenta).

slide 6

In the RGB color rendering system, the color palette is formed by adding red, green, and blue colors.

Slide 7

Color encoding at 24-bit color depth

With a color depth of 24 bits, 8 bits are allocated for encoding each of the primary colors. In this case, N = 28 = 256 intensity levels are possible for each of the colors. Intensity levels are specified in decimal (minimum - 0 to maximum - 255) or binary (from 00000000 to 11111111) codes.

Slide 8

Slide 9

Decimal codes for the intensity of base colors.

Slide 10

Color palette in CMYK color rendering system.

When printing images on printers, a palette of colors in the CMY system is used. The main colors in it are Cyan - blue, Magenta - purple and Yellow - yellow. Colors in the CMY palette are formed by overlaying inks of base colors. The color of the Color palette can be determined using a formula in which the intensity of each paint is given as a percentage: Color = C + M + Y, where 0%

slide 11

A person perceives an image printed on paper in reflected light. If no paint is applied to the paper, then the incident white light is completely reflected and we see a white sheet of paper. If paints are applied, they absorb certain colors of the spectrum. Colors in the CMY palette are formed by subtracting certain colors from white light.

slide 12

When applied to paper, blue ink absorbs red light and reflects green and blue light, and we see blue. When applied to paper, magenta ink absorbs green light and reflects red and blue light, and we see magenta. When applied to paper, yellow ink absorbs blue light and reflects red and green light, and we see yellow.

slide 13

By mixing two colors of the CMY system, we get the base color in the RGB color system. If magenta and yellow are applied to paper, green and blue light will be absorbed, and we will see red. If we put blue and yellow paint on paper, then red and blue light will be absorbed, and we will see green color. If purple and cyan are applied to paper, green and red light will be absorbed, and we will see blue.

Slide 14

Mixing three colors - cyan, yellow and magenta - should lead to complete absorption of light, and we should see black. However, in practice, instead of black, a dirty brown color is obtained. Therefore, another, true black color is added to the color model. Since the letter B is already used to denote blue, the last letter in the English name for black is Black, i.e. K. The extended palette was called CMYK to denote black.

slide 15

Shaping colors in the CMYK color rendering system

In the CMYK color rendering system, a palette of colors is formed by superimposing cyan, magenta, yellow, and black inks.

slide 16

The RGB color rendering system is used in computer monitors, televisions and other technical devices that emit light. The CMYK color rendering system is used in printing, as printed documents are perceived by a person in reflected light. Inkjet printers use four cartridges containing the base colors of the color rendering system to produce high quality images.

Slide 17

Slide 18

The color palette in the HSB color rendering system.

The HSB color rendering system uses Hue (hue of color), Saturation (saturation) and Brightness (brightness) as basic parameters. The Hue parameter allows you to select a color hue from all colors of the optical spectrum: from red to violet (H = 0 - red, H = 120 - green, H = 240 - blue, H = 360 - violet). The Saturation parameter determines the percentage of "pure" hue and white (S = 0% - white, S = 100% - "pure" hue). The Brightness parameter determines the intensity of the color (the minimum value of B = 0 corresponds to black, the maximum value of B = 100 corresponds to the maximum brightness of the selected color shade).

Slide 19

In the HSB color rendering system, the color palette is formed by setting the values of a color's hue, saturation, and lightness.

Slide 20

slide 21

Homework

§1.1.3. pp. 15 – 21, control questions, Assignment for self-fulfillment 1.6. and 1.7.

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