File Types and Formats

File Types and Formats







In this blog I will be looking at file types and formats of digital graphics



Pixel



A pixels is a small square of colour on a display screen, one of many from which a raster image is composed of.



Image resolution



Image resolution is the detail an image holds. The term applies to raster digital images, film images, and other types of images.resoultion refers to the amout of pixels in are area of a imege. this is measured in DPI (Dot per inch),the higher the DPI value the more detailed the imege will be. Higher resolution means more pixels in a area , the lower the resolution the less pixels in the area.




Raster Images



A raster image is built up form pixels and is great for pictures because you can set each pixel to a certain colour but cannot be resized and because of this you wouldn’t use it for logo, maps or graphics a because you would need higher detail. Raster formats are JPEG, JPEG 2000, EXIF, TIFF or RAW



Vector Images



Vector images are made up from point’s to up make Sharpe line meaning the image can be re scaled to any size without being distorted but because the picture is made from points and lines you can change the colour of areas but vector images can’t do complex colours. Vectors are great for logos, maps and graphics.



As you can see from the picture bellow that raster image loss their quality when zoomed in, were vector you can still see the detail.

















Pixel colour intensity



Pixel intensity is the values of colour a certain pixel is. Pixel intensity is stored in two ways RBG which builds up colours for red, blue and green. CMYK uses Cyan, magenta, yellow and key (black) to build image, this is optimized for printing.



Compression



Lossless compression is a recreated version of the original file exactly where lossy compression gets rid of unnecessary parts to make it a smaller size.

Compression is useful because if you upload a massive file to your web page then it would take ages for someone to load the page, where if you compressed the image then the image is easier to load.



File types



TIF



The key features of a TIF file is that web pages don’t show them. TIF uses lossless compression they have from 1-bit to 48-bit colour, RGB, CMYK, LAB or indexed colour. TIF does not support transparency and animation. This filetype is best used for getting the best quality and maximum compatibility.



GIF



GIF file type is very good for web-graphics and has a smaller file size that JPG with graphics with few colours. GIF files use lossless compression GIF uses 1 to 8-bits. GIF files can hold transparency and animation. GIFs are best used for computer graphics that doesn’t have a lot of colours.















PNG



PNG files can provide transparency for 24-bit RGB images. This file type uses lossless compression it can also be indexed or RGB 1 to 42-bits, can support transparency and animation and PNG is used for getting the best quality.



JPG



JPG files can compress files to be very small but if this is done the quality will not be as good. JPG uses lossy compression and uses RGB, 24-bit or grayscale, 8-bit. This file type doesn’t support transparency or animation. This file type is used for compressing data into very small files.



BMP (Bitmap)



BMP does not use compression to store information. This file type can use either lossy or lossless compression. It is 32-bit and can’t support transparency or animation. BMP files can be best used for printable files while files like JPG and GIFs are used on the web.



PSD (Photoshop)



When you open a file in Photoshop that file automatically gets converted into a PSD file while it is in Photoshop. This file type uses lossless compression. It uses 32-bit and can hold transparency and animation. This file type is best used for editing graphics in Photoshop.