Pixels

Pixel- Short for picture element – ‘pixel’ – pix (picture) ‘el’ – (element) is the smallest single visual component abstract of an image. The physical size depends on the resolution settings for the colour display screen. If the display is set to its maximum resolution, the physical size of a pixel will equal the physical size of the dot size of the display.

 

The image contains thousands of pixels, each is made up of a cluster of dots.

 

Vector Graphics

• Vector Graphics (aka object-oriented graphics) are composed of paths and use mathematical relationships between points and the paths connecting them to describe an image.

• WMF
• AL
• EPS

·        Vector 

·         WMF - (Windows Metafile) WMF is a 16-bit format and stores a list of function calls that have to be issued to the Windows graphics layer GDI in order to restore the image. It can contain both vector information and bitmap information.  

 

 

·        EPS - (Encapsulated PostScript) is the next best thing if the graphics application you are using cannot read vector files.

These are files which contain the same mathematical descriptions as the vector files they are made from.

Even bitmaps can be saved in the EPS file format. EPS files are supported by almost all graphic applications. It is the most portable format for this reason.

It is best to use EPS files for all line art and illustrations because they can be reproduced at any size or resolution and still be shown exactly as they were drawn. Use them wherever native vector files cannot be used.

EPS files are pretty much self-contained files that describe an image or drawing, that can be placed within another PostScript document.

 

 

 

 

 

 

 

Bitmap Graphics

• Bitmap graphics (aka raster graphics) are a collection of individual pixels where each pixel can be a different colour or shade, put together to create an image. Most commonly used bitmap file formats include;  

• JPEG
• PNG
• TIFF
• BMP
• GIF

 

• Image or graphic file formats provide a standardized method of organizing and storing image data.

 

• Bitmap images require higher resolutions for a smooth appearance and are best used for photographs and images with subtle shading. 

 

 ·        BMP - (Bitmap) or DIB (Device Independent Bitmap) file format consists of either 3 or 4 parts. The first part is a header, this is followed by an information section, if the image is indexed colour then the palette follows, and last of all is the pixel data. The position of the image of the file is kept in the header. Information such as the image width and height, the type of compression, the number of colours is contained in the information header. 

 

 

·        JPEG – (Joint Photographic Experts Group) – Used best for photographic images. Unlike GIF files, the JPEG format can take advantage of the colours available to your monitor.

The JPEG format also uses compression for smaller files and faster downloads. However, unlike the compression method used in GIF files, the JPEG compression is “lossy” which means it deletes data in the process. Once a file is saved in JPEG format the data is permanently lost. If you want the entire image data available for use in the future, save the image using no compression or “lossless” and make JPEG copies from it.

• PNG – ‘ping’ was designed for transferring images on the Internet. It does not support animation. MNG (Multiple-image Network Graphics) is an extension to PNG that does. It was not intended for professional graphics, and so does not support other colour spaces (such as CMYK) cyan, magenta, yellow, and key (black), The CMYK model works by masking certain colours on white backgrounds (absorbing particular wavelengths of light). This is named subtractive because inks “subtract” brightness from white.

 

  

 

 

 

 

 

 

 

http://www.eastbywest.com/pub/vectorbitmap/

 

Colour Space

 

The RGB colour model (red, green, and blue) is an enhancer colour model where the three primary colours are added together in different ways to reproduce a broad collection of colours.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colour space is also the only independent colour space and the only one which represents the way the human eye views colour.

 

CMYK (cyan, magenta, yellow and black) pigments serve as filters, subtracting alternating amounts of red, green and blue from white light to produce a selective range of spectral colours.

 

The same colour display on a computer monitor may not match to that printed in a publication. Because printers sometimes use CMYK inks, so digital art must be converted to CMYK colour before print.

 

 

http://www.drycreekphoto.com/Learn/color_spaces.htm

 

Bits

Binary digits are a basic unit of information storage and communication in digital computing and digital information. It has become more popular in the usage on the World Wide Web due to its wide support and portability.

Both RAM and hard disk capacities are measured in bytes, as are file sizes when you examine them in a file viewer.(A bit is a binary digit, taking a value of either 0 or 1. For example, the number 10010111 is 8 bits long, or in most cases, one modern PC byte. Binary digits are a basic unit of information storage and communication in digital computing and digital information theory. 

 0 =     0
 1 =     1
 2 =    10
 3 =    11
 4 =   100
 5 =   101
 6 =   110
 7 =   111
 8 =  1000
 9 =  1001
10 =  1010
11 =  1011
12 =  1100
13 =  1101
14 =  1110
15 =  1111
16 = 10000
17 = 10001
18 = 10010
19 = 10011
20 = 10100

 

When you look at this sequence, 0 and 1 are the same for decimal and binary number systems. At the number 2, you see carrying first take place in the binary system. If a bit is 1, and you add 1 to it, the bit becomes 0 and the next bit becomes 1.

 

http://www.helpwithpcs.com/courses/binary-numbers.htm