Graphics file formats
Different graphics file formats and their uses
Each graphics file formats is a way of organising and saving image into computer system, each file format uses different structure that can be recognised by a program/software it was originally created, so it knows how to show graphics on the computer screen, how to print it, edit it and so on.
The native file format is default file format used by specific applications; it enables users to save graphics on any steps for future editing within the application and it will remain all the features of it.
For example, layer styles in Photoshop will only remain editable when the image saved in native Photoshop (PSD) format.
When sending image to another application - file will be converted to a standard image format (most common bitmap formats are TIFF, JPG, GIF, and PNG), that supported by the majority of graphics applications.
The exemption would be if transferring image between applications from the same Publisher.
For example, there shouldn't be a problem sending Adobe Illustrator files to Adobe Photoshop.
Some examples of some graphics applications and their file format:
- CDR - CorelDraw
- CPP - Corel Photo-Paint
- PSD - Adobe Photoshop
- PDD - Adobe Photo Deluxe
- AI - Adobe Illustrator
- UFO - Ulead Photo Impact
- PSP - Paint Shop Pro
- MIX - Microsoft Picture It and PhotoDraw
All image files are composed either of pixels or vector data.
Graphics that made up of thousands of small pixels (cells) called bitmap (raster) graphics and can be produced and edited with different bitmap software applications often know as painting applications, like Shop Pro, Photoshop and many others.
Main features of bitmap graphics over vectors:
- They are large in file size;
- Print quality can become lossless, when image enlarged or reduced in size;
- Scanned images, and images from digital camera can be edited in bitmap software packages.
Bitmap pictures can be used in many different publications such as magazines, newspapers, also in web page illustrations and many others.
Picture can be improved through editing each pixel, applying different shapes of brushes and pens, using pre-set effects, playing with layers etc.
Examples of different bitmap file formats:.bmp
Windows Bitmap file format commonly used by Microsoft Windows programs and the Windows operating system itself.
BMP files are uncompressed, for this reason they are quite large in file size.
Advantage is their simplicity and wide acceptance in Windows programs..raw
RAW refers to family of raw image formats that are option on some digital cameras.
Such formats use lossless compression, and have much smaller files sizes compare to full-size processed images from the same cameras.
Disadvantage is that many graphics programs and image editors may not accept such formats.png
Portable Network Graphics is a bitmapped file format that uses lossless data compression and due to different factors applied - may be vary in file sizes.
PNG file format was designed to improve and replace GIFs file format on the Internet and, as they do not require a patent licence.
A vector image made up from one or more separate objects, such as lines, circles and other shapes.
And each object can be manipulated individually without disturbing the others.
Software packages for creating vector graphics are known as drawing application, e.g.
CorelDraw, Autodesk CAD and Microsoft Visio.
Some features of vector graphics over bitmap:
- Have smaller file size;
- No loss of print quality when image enlarged;
A vector images are good for diagrams, maps, company's logo, clip art image etc.
Image it self can be edited and each point can be regrouped then.
It is important for user to know where exactly the end picture will be used, to make sure image saved in appropriate file format and have the right attributes, like resolution, colour depth, anti-aliasing, transparency, and compression.
Image resolution describes the detail that image hold.
Higher resolution means more image detail, which will also lead to increasing in file size.
Digital graphics have different resolutions for different purposes, for user it is important to know where exactly picture will be used and make attributes right.
If resolution is not high enough pictures might become blocky when trying to print; if graphics with high resolution used over the web - it will take longer to download a webpage.
Colour depth describes the number of bits representing the colour of a single pixel in a digital graphic; this is known as bits per pixel (bpp).
It is also important as it controls the file size and overall image quality.
8-bit colour depth is popular for web graphics, as they are small in file size and don't take long to load up.
Higher colour depth will give broader range of different colours used in a graphic.
Transparency is a feature in some vector and bitmap software packages allowing a light to pass through an object.
resolution, colour depth, anti-aliasing, transparency (indexed and alpha) and compression (lossy and lossless) and how they are used in the file formats you have identified.