There are various types of file formats involved in digital graphics. The formats used would include GIF, JPEG, TIFF, PNG and also BMP. A file format in digital graphics is what way an image is saved, this depends mostly on the type of image it is, whether it’s a pixilated image or a vector image i.e. geometric or in some cases there are formats that save both.
Vector Graphics
Vector Graphics involves the use of points, lines, curves, shapes and polygon(s) which are all involved in the mathematical equations. These are all used in presenting images in computer graphics. Vector is a word that is used in representation of both a quantity and a direction of something at the same time.
An example showing an image edited by Vector software versus and images edited by Bitmap.Bitmap
In computer digital graphics the word Bitmap is used as a type of memory organisation or image file format used to store digital images. It is a graphical representation of an image which has been stored as a two dimensional map of bits. A Bitmap is a map of bits that makes up a picture as long as you are sitting a reasonable distance away from the screen, most pictures shown on a computer are Bitmap.
Difference between Vector and Bitmap
Just by reading the definition of both Vector and Bitmap you would be able to tell that Vector has a stronger resolution on images than Bitmap. Vector images contain well-defined elements such as curves and shapes of various colours. On the other hand Bitmap images do not rely on mathematical formulas or equations to be able to define their images or colours of images.
J-Peg
JPEG is a picture format that is a commonly used method of lossy compression. JPEG is used as most image file formats. It is the most commonly use image format of a digital camera. It is the most common format that is used for storing and transmitting digital images onto the world wide web. JPEG file format is commonly used for photographs and images that have millions of colours.
GIF
GIF which is also known as Graphics Interchange Format is a digital image format that stores images of up to 256 colours. GIF is a format that uses lossless compression method. GIF compressed image files can be quickly transferred over the Internet or a network. GIF file formats are commonly used for small icons and animated images but they lack the colour range to be used for high-quality photos.
The differences between JPEG and GIF file formats:
JPEG is a file format that is used on images that have millions of colours and are easily stored and trasnmitted onto the world wide web, whereas GIF is a file format that only uses images with 256 colours or less and is commonly used on small icons and animated images. GIF is the cheapest and easiest way of putting animation online whereas JPEG is only commonly able to put digital images online. JPEG format uses the Lossy compression method and GIF uses the Lossless compression method.
File format compression techniques
There are two types of format compression techniques, Lossy and Lossless. Lossy format compression is a format method that loses or discardes a percentage of its data in order to achieve its goal. With the result of the format compression the data yields that content that is different from the rest though is still similar in a way so that it may be useful in some way. Lossy compression is a most commonly used method to compress multimedia data such as:
- Audio
- Video
- Still Images
Original Picture
Lossy Compression Low compression
Lossy Compression Medium Compression
Lossy Compression High Compression
Lossless format compression allows the original piece of data to be reconstructed fom the compressed data. Lossless data compression allow an approximation of an original piece of data to be reconstructed. Lossless data compression is used in many different applications such as:
- ZIP file format
- Unix Tool gzip
Resolution and Colour Depth
Resolution
The resolution of an image is determined by the number of individual points that are used to make up the image, this is whether it is the number of pixels that make up a screen image or the number of dots that make up a printed images.
The more points there are to create an image, the more detail an image can resolve and sharpen its appearances when viewed by someone.
When using a BITMAP format, no matter what the resolution is, the information needs to be stored for each pixel or printed dot. This means that the higher the resolution is, the more information needs to be stored for an image of any given size.
This generally doesn’t apply to VECTOR graphics, because the decision about the resolution only needs to be made when the image is printed, or used as a BITMAP.
Colour Depth
Colour Depth is used to explain or describe the maximum number of colours that are used in an image. Generally the higher the number of colours then the more realistic the image will appear to someone. With BITMAP images the chosen colour depth will affect the final file size.
Here are some examples of the types of formats used in colour depth:
Monochrome (e.g. Black & White)
Monochrome is the smallest storage requirement, because you only need to know whether the pixel should be on or off. The information for each pixel can be stored in a BIT, or put another way. You can store the information for eight pixels in one BYTE of storage space.
16 BIT Colour (High Colour)
Although the 16 BIT Colour format is not as common now as a few years ago, this format uses two BYTES to store the information, one BYTE is used for the colour and the other one is used for the particular shade of the colour. This would give a total of 65,536 colours (256x256). So this is why each pixel requires at least two BYTES of storage space.
24 BIT Colour
This format stores the Red, Blue and Green value for each pixel. Each of these values can be one of 256 values, which gives a total of 16,777,216 colours (256x256x256). Using at least 16 million colours allows for the images to be very photorealistic, however this increases the storage space requirements to three BYTES for each pixel.
32 BIT Colour (True Colour)
This type of format uses the same format as the 24 BIT for the Red, Blue and Green colours but also stores the transparency information for each of the pixels. This allows each of the pixels to be one of 256 values from fully opaque to fully transparent. But because of the extra transparency information. The storage space for each pixel now requires four BYTES.
