Bitmap vs Vector How computers work with photographs

Bitmap vs. Vector How computers work with photographs and drawings

• Vector graphics is the creation of digital images through a sequence of commands or mathematical statements that place lines and shapes in a given two-dimensional or threedimensional space. In physics, a vector is a representation of both a quantity and a direction at the same time.

vector graphics are comprised of paths, which are defined by a start and end point, along with other points, curves, and angles along the way. A path can be a line, a square, a triangle, or a curvy shape. These paths can be used to create simple drawings or complex diagrams.

• Because vector-based images are not made up of a specific number of dots, they can be scaled to a larger size and not lose any image quality. • Common types of vector graphics include Adobe Illustrator, Macromedia Freehand, Many Flash animations also use vector graphics, since they scale better and typically take up less space than bitmap images.

• Vector Image File Formats. • EPS - Adobe's EPS format (Encapsulated Post. Script) is perhaps the most common vector image format. It is the standard interchange format in the print industry. It is widely supported as an export format, but due to the complexity of the full format specification, • AI - The native format of Adobe Illustrator is the AI format (Adobe Illustrator Artwork), a modified version of the older EPS format. The AI format is fairly widely supported,

• PDF - Adobe's PDF format (Portable Document Format) is very widely used as a general purpose platform-independent document format. And while it is not exclusively used as such, it is also a very good vector image format. Adobe gives away the Acrobat PDF reader, but sells the tools required to create PDF files (third party tools that perform the same task are also for sale). Those tools work with any program that is able to print. Support for reading and editing PDF files is much more limited.

• SVG - The W 3 C standard vector image format is called SVG (Scalable Vector Graphics). Inkscape and recent versions of Adobe Illustrator and Corel. DRAW have good support for reading and writing SVG. Further information on the SVG format may be found on the official SVG website. • DXF - Drawing e. Xchange Format. A CAD format from Autodesk, used by CAD tools from many different vendors. Some programs have difficulty reading DXF files with splines (curves), so the Desktop Edition supports line+spline as well as line only output modes

• Bitmap Image File Formats. • JPEG/JPG - One of the most widely-used image formats is the JPEG format (Joint Photographers' Expert Group). This format has excellent compression characteristics and has the nice feature that the user may specify what level of compression they desire, trading off fidelity for file size. • We do not recommend using JPEG files for rasterized vector art, as the compression artifacts substantially degrade the quality of the image near edges. • PNG - The best of the lossless image formats is called PNG (Portable Network Graphics). This format is widely supported by web browsers and image viewers/editors. • Vector Magic recommends using the PNG format when storing logos as bitmaps.

• BMP - There actually several BMP formats (Bit. Ma. P). Windows and Macintosh have their own formats, both of which are called BMP. Most modern image editing tools are able to read both. • In any case, all of the variants of BMP should be avoided when possible, as they use little to no compression and consequently have unnecessarily large file sizes. • TIFF/TIF - This format (Tagged Image File Format) is used to store raw bitmap data by some programs and devices such as scanners. This format comes in a compressed an uncompressed variant. The former is comparable to PNG, while the latter is more like BMP

Definition: Bitmap • Bitmapped images: • Photographs, computer paintings, videos • Specific number of dots (or pixels) across and down (160 x 120, 800 x 600, 1400 x 1050) • Dots spread out or squeeze together as image size changes • Number of dots remains the same • Photoshop, Paint, Quick. Time

“Maps” of Dots

Bitmap Examples

Making Bitmaps Bigger 100% (900 x 983 dpi) 200% 500%

Warning! • • DPI is critical! Printers: 300 dpi, 600 dpi Monitors: 72 dpi (Internet pictures) If you download a picture from the Internet to print out, make sure it’s BIG!

Definition: Vector • Vector-based image: • • • Drawings, animation Points, lines, fill, shapes Instructions to computer Quality remains same as image size changes Illustrator, Word “draw”, Corel Draw

Points, Lines and Fill

Vector Examples

Vector Image 100% 200% 500%

Bitmap vs. Vector • Bitmap • Photographs • Dots (pixels) • Photoshop • Vector • Drawings • Points, lines, fill • Illustrator

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