LESSON 14 SELECTING AND CHANGING COLOURS STRUCTURE 14.0
OBJECTIVES
14.1
INTRODUCTION
14.2
W ORKING WITH COLOUR 14.2.1 14.2.2 14.2.3 14.2.4 14.2.5
14.3
CHOOSING COLOURS USING THE DEFAULT COLOUR PALETTE CHOOSING COLOURS USING FIXED OR CUSTOM COLOUR PALETTE CHOOSING COLOURS USING COLOUR VIEWERS CHOOSING COLOURS USING COLOUR HARMONIES CHOOSING COLOURS USING COLOUR BLENDS
UNDERSTANDING COLOUR MODELS 14.3.1 14.3.2 14.3.3 14.3.4
CMYK COLOUR MODEL RGB COLOUR MODEL HSB COLOUR MODEL GRAYSCALE COLOUR MODEL
14.4
TEXTURE FILL
14.5
ASSIGNMENTS 14.5.1 CLASS ASSIGNMENTS 14.5.2 HOME ASSIGNMENTS
14.6
SUMMING UP
14.7
POSSIBLE ANSWERS TO SELF-CHECK QUESTIONS
14.8
TERMINAL QUESTIONS
14.9
REFERENCES AND SUGGESTED FURTHER READING
14.10 GLOSSARY
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14. SELECTING AND CHANGING COLOURS This lesson will be of a great help in understanding colour structure and the system of nomenclature build up on a computer. Different colour models on the computer system will be studied and the method of their selection will be discussed so as to make your working with the colors quicker and easier. It will also help you to brush up your skills by doing some activities on creating and changing texture fills in various shapes in Corel draw graphics.
14.0 Objectives This lesson will help you: •
To understand various colour models in computer graphics
•
To work efficiently with different fill options of texture on the computer
•
In designing with Corel Draw Graphics.
14.1 Introduction In colour theory you came across the term “analogous colours". It refers to a series of colours that are of the same hue, but a different shade or saturation value. Look at the image (Fig. 14.1) to see what it means.
Fig. 14.1
Here is a series of brown colours going from a dark shade to a light one. You should be able to feel a sense of something with this colour scheme. We will talk about that later. What we have here is a series of analogous colours. Brown is not the best example, so let us look at blue (Fig. 14.2).
Fig. 14.2
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Here we have the same series, but with blues. Analogous colours can be any hue. If you were using a Grey scale version, they would go from black to white through a series of grays. The level of saturation in colour is an important parameter in selecting colour scheme. Take a look at the image in Fig. 14.3. This is the blue image that has been completely saturated. See how different it feels from the previous image.
Fig. 14.3
14.2 Working with Colour Your application allows you to choose and create colours using a wide variety of industry-standard palettes, colour mixers, and colour models. A palette is a collection of colour swatches. You can create and edit custom colour palettes to store frequently used colours for future use. You can also customize how colour palettes display on the screen by changing the size of swatches, the number of rows in palettes, and other properties. You can choose, fill and outline colours using fixed or custom colour palettes, colour viewers, colour harmonies, or colour blends. A range of colours are displayed in a colour model, such as RGB (red, green, blue), CMY (cyan, magenta, yellow), CMYK (cyan, magenta, yellow, black), HSB (hue, saturation, brightness), HLS (hue, lightness, saturation), and CIE L*a*b (Lab). 14.2.1 Choosing colours using the default colour palette You can choose fill and outline colours using the default palette, which contains 99 colours from the CMYK colour model. The selected fill and outline colours display in the colour swatches on the status bar. 14.2.2 Choosing a colour using fixed or custom colour palettes Third-party manufacturers provide fixed colour palettes. Some examples of these are PANTONE, HKS colours, and TRUMATCH. It may be useful to have on hand a manufacturer's swatch book, which is a collection of colour samples that shows exactly what each colour looks like when printed. Custom colour palettes can include colours from any colour model or fixed colour palette. You can save a custom colour palette for future use. 14.2.3 Choosing a colour using colour viewers Colour viewers give a representation of a range of colours using either one-dimensional or three-dimensional shapes. The default colour viewer is based on the HSB colour model, but you can also use this viewer to choose CMYK, CMY, or RGB colors. 14.2.4 Choosing a colour using colour harmonies 3
Colour harmonies work by superimposing a shape, such as a rectangle or a triangle, over a colour wheel. Each vertical row in the colour grid begins with the colour located at one of the points on the superimposed shape. The colors at each corner of the shape are always complementary, contrasting, or harmonious, depending on the shape you choose. The colour harmonies allow you to choose the colour model you prefer to use, and are most useful when you're choosing several colours for a project. 14.2.5 Choosing a colour using colour blends When you choose a colour using colour blends, you combine base colours to get the colour you want. The colour blender displays a grid of colours that it creates from the four base colours you choose.
14.3 Understanding Colour Models You need a precise method to define colours. Colour models provide various methods to define colours, each model defining colours through the use of specific colour components. There are a range of colour models to choose from when creating graphics. 14.3.1 CMYK colour model The CMYK colour model defines colour using the following components: • • • •
cyan (C) magenta (M) yellow (Y) black (K)
The cyan, magenta, yellow, and black components are the amounts of cyan, magenta, yellow, and black ink that a CMYK colour contains and are measured in percent from 0 to 100. The CMYK colour model is a subtractive colour model. Subtractive colour models use reflected light to display colour. Printed materials are produced using the CMYK colour model. When you combine cyan, magenta, yellow, and black, so that the value of each component is 100, the result is black. When the value of each component is 0, the result is pure white. 14.3.2 RGB colour model The RGB colour model defines colour using the following components: • • •
red (R) green (G) blue (B)
The red, green, and blue components are the amounts of red, green, and blue light that an RGB colour contains and are measured in values ranging from 0 to 255. When you add red light, blue light, and green light together, so that the 4
value of each component is 255, the colour white displays. When the value of each component is 0, the result is pure black. 14.3.3 HSB colour model The HSB colour model defines colour using the following components: • • •
hue (H) saturation (S) brightness (B)
Hue describes the pigment of a colour and is measured in degrees from 0 to 359 (for example, 0 degree is red, 60 degrees yellow, 120 degrees green, 180 degrees cyan, 240 degrees blue, and 300 degrees magenta). Saturation describes the vividness or dullness of a colour and is measured in percentage from 0 to 100 (the higher the percentage, the more vivid the colour). Brightness describes the amount of white that the colour contains and is measured in percentage from 0 to 100 (the higher the percentage, the brighter the colour). 14.3.4 Grayscale colour model The Grayscale colour model defines colour using only one component, lightness, and is measured in values ranging from 0 to 255. Each Grayscale colour has equal values of the red, green, and blue components of the RGB colour model. Colour is mixed differently depending on the medium, i.e., dye, type of dye, oils, acrylics, water colour, fabric paint and even mixing with the help of some computer software. These colours are not exact and will show up differently on different monitors. However, you may get an idea of what a good colour wheel would do for you. Some "rules" to help your colour intuition: •
Different rules apply to different fiber techniques as well: weft has to be considered with weaving as prints need to be considered with quilting.
•
Surface design requires knowing what colour interaction is going to take place when one colour is laid on top of another.
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Pattern weaving shows up better with a blending of colour or tone-ontone, if not a solid.
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Lace knitting shows up better in light colour ways.
Corel Draw supports the following colour modes: Black-and-White (1-bit)
Grayscale (8-bit)
Duotone (8-bit)
Paletted (8-bit) 5
RGB Colour (24-bit)
Lab Colour (24-bit)
CMYK Colour (32-bit)
14.4 Texture Fill Texture Fill puts the power of a texture editor at your fingertips. Hundreds of preset textures can be edited both randomly and through precise settings, resulting in millions of possible texture fills (Fig. 14.4). Texture fills are accomplished by selecting an object with the Pick Tool and clicking on the Fill Tool to open the fly-out. Click on the forth icon to open the Texture Fill window. Fig. 14.4 Texture Fill
Self-check Questions 1. Name the different colour models of Corel Draw 2. Define - Hue, Saturation, Brightness 3. What is a colour palette? 4. Write the name of colour in RGB and CMYK colour Model. 5. For producing Black and White in RGB model, what will be the value of R.G.B.?
Activity 1. Creating Texture Fill •
Open Texture Fill Window
Create a rectangle at least 3" wide and high, with no fill (Fig. 14.5). Select the rectangle with the Pick Tool. Choose the Fill Tool from the Toolbox to open the fly-out. Choose the fourth icon to open the Texture Fill Window (Fig. 14.6). •
Choose Texture Fill Library
Choose a collection of patterns from the Texture Library fly-out. Each of the libraries contains a separate selection of textures.
6 Fig. 14.5
•
Choose Texture Choose texture from the Texture List. Keep in mind that you can adjust many of the properties of the texture and can substitute colours. The sample in Fig. 14.7 is Cotton Candy from the Samples 6 library.
Fig. 14.7
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Set Tiling Options
Fig. 14.8
•
Depending on the size of your object, you may have unattractive edges due to tiling. Not all textures repeat smoothly, and you can set the size of the tile to exceed your object to prevent tiling (Fig. 14.8). You can also skew or rotate your texture fill, offset the tiling rows or columns and change the position of the pattern. Click on the Tiling button in the Texture Fill window to access all the above options.
Set Texture Fill colour
Fig. 14.9
Click on the Sky button to change the pink colour (Fig. 14.9). Choose one of the preset colours or click ‘Others’ for the full range of CorelDraw colours. (Choosing a colour that is not from the RGB colour model will bring a warning that the colour will be converted to RGB. Slight colour shifting can occur.) Click on the Clouds button to change the white colour. Each texture will have a different naming system for the colours, but samples are shown of each colour to make editing easier. Click on preview to see the results.
2. Change Texture Properties There are unlimited variations for each texture. You can easily view random variations by pressing the Preview window. Each click will present a slightly different combination. You can also manually adjust a variety of properties in the lower left corner of the Texture Fill window. You can toggle locks for each property on and off. Experiment with variations of many styles to learn how to find exactly the right combination for your needs. Two versions of the same texture and colour are shown in Fig. 14.10. Fig. 14.10
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3. To copy a fill to another object •
Open the Eyedropper flyout, and click the Eyedropper tool. Eyedropper, enables you to select a fill colour from an object in a drawing.
•
On the property bar, click one of the following buttons:
•
Fill/outline lets you choose the colour of the object's fill or outline.
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1x1 lets you choose the average colour in a 1X1 pixel area of the object.
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3x3 lets you choose the average colour in a 3X3 pixel area of the object.
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5x5 lets you choose the average colour in a 5X5 pixel area of the object.
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Selection lets you choose the average colour in marquee selected areas of the object.
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Click the object whose fill you want to copy.
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Open the Eyedropper flyout, and click the Paint bucket tool.
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Click the object to which you want to apply the fill. Eyedropper tool also allows you to fill an object with a colour that you select from another object.
4. Draw a circle •
Open the Ellipse flyout, and click the Ellipse tool. Hold down Ctrl Key, and drag in the drawing window until the circle is of the size you want.
5. Apply uniform fills Uniform fill is a type of fill used to apply one solid Colour to these objects. •
Select an object.
•
Open the Interactive fill flyout, and click the Interactive fill tool.
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Choose Uniform fill from the Fill type list box on the property bar.
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Specify the settings you want on the property bar, and press Enter.
You can also fill a selected object by clicking a colour on the colour palette. You can mix colours in a uniform fill by selecting a filled object, pressing Ctrl Key, and clicking another colour on the colour palette. 6. Draw a square inside the Circle Open the Rectangle flyout, and click the Rectangle tool. Hold down Ctrl Key, and drag in the drawing window until the square is the size you want. 8
7. Applying texture fills into the Square A texture fill is a randomly generated fill that you can use to give your objects a natural appearance. CorelDraw provides preset textures, and each texture has a set of options that you can change. You can use colours from any colour model or palette to customize texture fills. Texture fills can hold only RGB colours. However, other colour models and palettes can be used as reference to select colours. For information about Colour models, see "Understanding Colour models." You can change the tile size of texture fills. Increasing the resolution of a texture tile increases the accuracy of the fill. You can also specify exactly where these fills begin by setting the tile origin. CorelDraw also lets you offset tiles in a fill. Adjusting the horizontal or vertical position of the first tile, relative to the top of the object, affects the rest of the fill. You can rotate, skew, adjust the tile size, and change the center of the texture to create a custom fill. If you want a texture fill to change according to the actions you perform on the filled object, you can specify that you want it to transform with the object. For example, if you enlarge an object filled with a texture that transforms, the texture becomes larger instead of increasing the number of tiles. Texture fills are powerful features that can enhance a drawing.
14.5 Assignments 14.5.1 Class assignments i) Apply a texture fill • • • • •
Draw an object. Select the object. Open the Fill flyout, and click the Texture fill dialog button. Choose a texture library from the Texture library list box. Choose a texture from the Texture list.
You can also: i) Create a custom texture fill:
Specify the settings you want in the Style name area.
ii) Change the size of texture tiles:
Click Tiling, and type values in the Width and Height boxes.
iii) Set the tile origin of a texture fill:
Click Tiling, and type values in the X and Y boxes in the Origin area.
iv) Offset the tile origin of a texture fill:
Click Tiling, and enable the Row or Column option. Type an amount of offset in the % of tile size box. 9
v) Rotate a texture fill:
Click Tiling, and type a value in the Rotate box.
vi) Skew a texture fill:
Click Tiling, and type a value in the Skew box.
vii) Mirror a texture fill:
Click Tiling, and enable the Mirror fill check box.
Note: You can modify the texture you choose from the texture library and save it to another library, but you cannot save textures to or overwrite textures in the texture library. Tip: You can save a custom texture fill by clicking the plus sign (+) in the Texture fill dialog box, and typing a name in the Texture name box.
14.5.2 Home assignments i) Draw a circle and Draw a square inside the Circle and. Apply different texture fill in the two areas as you like using a suitable colour harmony.
14.6 Summing Up We learnt in this lesson the techniques of colour and texture management on computers. We learned to select and change the colour using default colour palette, custom colour palette, colors viewers, harmonies and blends. Then various colour models on computers are explained. Then there are number of activities taken up on creating texture fill, changing texture properties, copying a fill to another object, drawing and applying texture on the objects,
14.7 Possible Answers to Self-check Questions 1. 1. CMY, 2. CMYK, 3. RGB, 4. HSB, 5. HLS, 6. Lab, 7. Grayscale 2. Hue 3. A palette is a collection of colour swatches. You can create and edit custom colour palettes to store frequently used colours for future use. 4. Red, Green, Blue: and Cyan, Magenta, Yellow. 5. The value of all components is 0 for Pure Black and the value of all is 255 for pure white.
14.8 Terminal Questions 1. What do you understand by colour models and how many types of colour models are available? 2. What do you understand by analogue colour schemes. 10
3. Explain your answer by showing two analogous colour schemes, of different colours.
14.9 References Suggested Further Reading Internet Websites: 1.
Colour Wheel Pro:
2.
Corel Draw Help Menu
3.
Online Tutorials on Graphics Software
http://www.color-wheel-pro.com
14.10 Glossary 1.
Analogous
Correspondent
2.
Hue
Take on color or become colored
3.
Palette
A flat surface on which artists mix paints and the range of colors used
4.
Swatch
Piece of cloth
5.
Superimpose
Lay over
6.
Vivid
Having striking colour
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