Chapter 4: Images

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Chapter 4: Images by Mind Map: Chapter 4: Images

1. Subtractive color

1.1. In the subtractive color method, color is created by combining colored media such as paints or ink.

1.2. The colored media absorb (or subtract) some parts of the color spectrum of light and reflect the others back to the eye.

1.3. Subtractive color is the process used to create color in printing.

1.4. The printed page consists of tiny halftone dots of three primary colors: cyan, magenta, and yellow (CMY).

2. Making Still Images

2.1. Still images are generated in two ways

2.1.1. Bitmaps (raster)

2.1.1.1. Bitmap is derived from the words “bit,” which means the simplest element in digital world, an electronic digit that is either on or off, black or white, or true (1) or false (0).

2.1.1.2. A bitmap is a simple matrix of the tiny dots that form an image and are displayed on a screen or printed.

2.1.1.3. Bitmapped images can have varying bit and color depths.

2.1.1.4. A bitmap is made up of individual dots or picture elements known as pixels or pels

2.1.1.5. Bitmapped images can have varying bit and color depths

2.1.1.6. Bitmaps are an image format suited for creation of:

2.1.1.6.1. Photo-realistic images

2.1.1.6.2. Complex drawings requiring fine detail

2.1.1.7. Advantages

2.1.1.7.1. Can have different textures on the drawings; detailed and comprehensive

2.1.1.8. Disadvantages

2.1.1.8.1. Large file size

2.1.1.8.2. Not easy to make modification to objects/drawings

2.1.1.8.3. Resizing a bitmapped image requires either duplicating pixels.

2.1.1.8.4. Graphics become "blocky" when the size is increased.

2.1.2. Vector-drawn graphics

2.2. Bitmaps editors are called painting program, vector editors are called drawing program.

2.3. Image editing programs enable the user to

2.3.1. Enhance and make composite images

2.3.2. Alter and distort images

2.3.3. Add and delete elements

2.3.4. Morph (manipulate still images to create animated transformations), allow to smoothly blend two images so that one image seems to melt into the next

2.4. Users can scan images from conventional sources and make necessary alterations and manipulations.

3. Bitmap Sources

3.1. Where do bitmaps come from?

3.1.1. Capture a bitmap using a camera.

3.1.2. Capture a bitmap from a photo or other artwork using a scanner to digitize the image.

3.1.3. Make a bitmap from scratch with a paint or drawing program

3.1.4. Grab a bitmap from an active computer screen with a screen capture program, then paste it into a paint program or your applications

3.1.5. Get from the suppliers of clip arts, and from photo-graph suppliers.

3.1.6. Libraries of clip art are available online and images are downloadable (usually for a fee)

3.1.7. Download from an image from website – be aware of who owns the copyright to the image you wish to use and what is required to reproduce the image legally

3.1.8. Legal rights protecting use of images from clip art galleries fall into three basic groupings:

3.1.8.1. Public domain images were either never protected by a copyright or their copyright has ended (freely used without obtain permission/license fee)

3.1.8.2. Royalty-free images are purchased and then used without paying addition license fees

3.1.8.3. Right-managed images require you negotiate with the right holder regarding terms for using the image and how much you will pay for that use

3.2. The industry-standard programs for bitmap painting and editing are

3.2.1. Adobe’s Photoshop and Illustrator

3.2.2. Corel’s Painter and CorelDraw

4. Vector Drawing

4.1. Vector-drawn graphics

4.1.1. Vector-drawn graphics

4.1.2. How vector-drawn images work

4.1.3. Vector-drawn images versus bitmaps

4.2. Vector-drawn images are used in the following areas

4.2.1. Computer-aided design (CAD) programs needed by architects and engineers

4.2.2. Graphic artists designing for the print media

4.2.3. 3-D animation programs – changes of position, rotation, and shading of light

4.2.4. Applications requiring drawing of graphic shapes

4.2.5. How vector-drawn images work

4.2.5.1. A vector is a line that is described by the location of its two endpoints.

4.2.5.2. Vector drawing makes use of Cartesian coordinates.

4.2.5.3. Cartesian coordinates are numbers that describe a point in two- or three-dimensional space as the intersection of the X, Y, and Z axes

5. Vector Graphics

5.1. Advantages

5.1.1. Vector images use less memory space.

5.1.2. For the Web, pages that use vector graphics in plug-ins download faster and, when used for animation, draw faster than bitmaps.

5.1.3. Vector objects are easily scalable without loss of resolution or image quality.

5.1.4. Easy to edit the drawings as each object is independent of the other.

5.2. Disadvantages

5.2.1. Objects/drawings cannot have texture.

5.2.2. cannot be used for photorealistic images.

6. Texture

6.1. refers to the properties held and sensations caused by the external surface of objects received through the sense of touch.

6.2. the feel of a surface or a fabric; "the wall had a smooth texture

7. 3-D drawing and rendering

7.1. 3-D animation tools

7.1.1. Daz3D

7.1.2. Form*Z

7.1.3. NewTek′s Lightwave

7.1.4. Autodesk’s Maya

7.1.5. Trimble’s SketchUp

7.2. Features of a 3-D application

7.2.1. Modeling - Placing all the elements into 3-D space.

7.2.2. Extrusion - The shape of a plane surface extends some distance

7.2.3. Lathing - A profile of the shape is rotated around a defined axis

8. Rendering

8.1. Rendering - Use of intricate algorithms to apply user-specified effects

8.2. Takes many hours for a single image

9. Colors and Palettes in Multimedia

9.1. Understanding natural light and color models

9.1.1. Additive color

9.1.2. Subtractive color

9.2. Additive color

9.2.1. In the additive color method, a color is created by combining colored light sources in three primary colors - red, green, and blue (RGB).

9.2.2. TV and computer monitors use this method.

9.3. Dithering

9.3.1. Usually, digitised images are 24 bit, 16 million colour depth

9.3.2. If display system is limited to less than 16 million colours, the image must be transformed for display in the lesser colour environment (colour dithering).

9.3.3. Dithering is a process whereby the color value of each pixel is changed to the closest matching color value in the target palette.

9.3.4. This is done using a mathematical algorithm.

10. Image File Types Used in Multimedia

10.1. Macintosh formats

10.1.1. On the Macintosh, the most commonly used format is PICT.

10.1.2. PICT is a versatile format developed by Apple.

10.2. Windows formats

10.2.1. The most commonly used image file format on Windows is DIB, also known as BMP.

10.2.1.1. DIB stands for device-independent bitmaps.

10.3. Cross-platform formats

10.3.1. JPEG, GIF, and PNG – Most commonly used format on the Web

10.3.1.1. JPEG(Joint Photographic Expert Group )

10.3.1.1.1. Commonly used standard method of compression for photographic images.

10.3.1.1.2. Support a maximum of 16.7 million colors

10.3.1.1.3. Lossy compression technique: Losses some image information.

10.3.1.1.4. Degradation of image possible with repeated editing and saving

10.3.1.1.5. No transparency

10.3.1.1.6. No animation

10.3.1.2. GIF

10.3.1.2.1. 8-bit per pixel, bitmap image format commonly used by the world wide web

10.3.1.2.2. Uses lossless compression technique.

10.3.1.2.3. Image can have transparent portion.

10.3.1.2.4. Animation possible.

10.3.1.3. PNG (Portable Network Graphic )

10.3.1.3.1. Supports more than 16.7 million colors.

10.3.1.3.2. Use Lossless Compression Technique

10.3.1.3.3. Image can have transparent portion

10.3.1.3.4. No animation

10.3.1.4. Image File Compression

10.3.1.4.1. lossless compression

10.3.1.4.2. Lossy compression