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Discuss the impact that file format, compression techniques, image resolution and colour depth have on file size and image quality In this report, I will talk about how users need to use different file formats, different compression techniques, and different image resolutions and different colour depths. Photoshop This format lets you open the file straight into Photoshop and edit the image and use all the features of the software however, the main problem is that you can only open this file with Adobe Photoshop and the file is relatively large so it may take up a lot of space on your computer. Also you have to pay for Photoshop which might be difficult for some people. GIF (Graphics Interchange Format) The Graphics Interchange Format (GIF) is a bitmap image format that is used a lot for images on the internet because it is perfect to use due to support, compatibility and not too large in space so it does not take up loads of space and a long time to upload to be used on Webpages. The disadvantage is that it only uses RGB and grayscale therefore the quality of the image will not be as good as other image formats, so this isn’t the best format to use when it comes to image quality but it is a good format for logos with solid coloured areas. GIF file format is also a good file format for the use of animations which are eye catching when used on websites. JPEG (Joint photographic experts group) JPEG is a raster file, which stands for Joint Photographic Experts Group format; this is a format that is also widely used online on websites and on other different online servers because of its compatibility, size and quality of image. JPEG format supports CMYK, RGB, and Grayscale colour modes so the quality of the image is better than some other file formats as they don’t all support CMYK. This file format does not take up a lot of space and still has a good quality image. As this image is commonly used it can be opened with virtually any image software so this can be very useful so you won’t need special software to edit the image or view it due to its file format. The disadvantage is that when you enlarge the image the quality will degrade so you may not want to enlarge it as pixilation might occur. Bitmap file The BMP file format is an image file format used to store bitmap digital images. Many graphical user interfaces (GUI) use bitmaps. A bitmap image is an image that is made up of tiny square, and the way the squares are arranged create an image; this is how photographs are created. The leading disadvantage of the BMP file format is that the larger the resolution the bigger the actual file itself, so to have the image in a high resolution it will take up a lot of space. The second disadvantage of this format is that when you enlarge the image the image quality worsens, this is called pixilation.

TIFF/TIF (tagged image file format) Tagged-Image File Format (TIFF, TIF) is a flexible bitmap image format that is supported by lots of software applications so this is very useful when it comes to editing or viewing the image. It is also a very useful file format as virtually all desktop scanners can produce TIFF images. The software application Adobe Photoshop CS CS2 CS3 etc. all support with format and allow you to open them using the software application but software before CS did not allow you to open up files that are less than 2GB in size. TIFF format supports CMYK, RGB, Lab, Indexed Colour, and Grayscale images with alpha channels and Bitmap mode images without alpha channels. TIFF image files have a bit depth of 8, 16, or 32 bits per channel. Compression techniques There are two techniques of compressing a file to make it smaller and they are Lossy and Lossless. Lossy The first compression technique I am going to talk about is Lossy, this is a technique that affects the quality of the image, when you compress an image using Lossy it worsens the quality of the image because when it compresses the image it loses some of the image data, so when the data is lost part of the image is lost so pixilation occurs and you may see the image turns into loads of very small squares that form the image. However Lossy does do the job of compressing the file as when it is compressed it will be considerably smaller than it was beforehand. Lossless The second technique is Lossless compression; this is a technique that is better than lossy as is does not worsen the image quality when compressed. Lossless also does the job as it compresses the file and makes it smaller and the image will take up less space on the hard drive and will also make it easier for it to be uploaded to a webpage. Image quality and resolution The resolution of an image is decided by the number points that make up the image, that can be dependent on the pixels in that precise image on a monitor screen, or the number of dots that make up a printed image so the more points that are used to create an image, the better the quality and detail of the image. When it comes to the different file formats it is very clear that the larger the image file the better the quality of the image and the if the image file size is small the quality is certain to be poor too, so overall the resolution is directly linked to the image size. It is a disadvantage that an image in large in size as it will take up a lot of space on your hard drive however it might be very important to have a good quality image so it won’t matter it takes up a lot of space.

Colour depth Colour depth is a way to describe the maximum amount of colour used in an image, so the more colours in the image the more detailed the image will look. The colour depth affects the final size of the image, as is resolution. There are many different colour depths such as, monochrome, which is the simplest colour depth as all we need to know is whether the pixel is on or off e.g. black and white image. Here are the different colour depths: 16 Bit Colour: this format uses two Bytes to store the information, one Byte for the colour and one Byte for the shade of the colour. 24 Bit Colour: This format stores the Red, Green and Blue for each pixel. So 256 values for each colour so giving a total of 16,777,216 colours (256x256x256). Having 16 million colours allows the quality of the image to be realistic and good quality however as the colour depth is higher and there are more colours that mean that the storage space will also be advanced. 32 Bit Colour (True Colour): This colour depth is known as “True Colour”, this format uses the same format as above for the Red, Green and Blue colours but also stores transparency information for each pixel. So it permits each of the 256 pixels to be fully opaque to fully transparent which is very important when it comes to having a good quality image, however it does mean the image size will be even larger. So colour depth is very important when it comes to having a good quality image and it also effects the size of the image, the better the colour depth the larger the size of the file but it does mean that the image will consist of more detailed colours so a more realistic image. Overall it is clear that there are some file formats that are clearly better than other file formats and it is clear some file formats are better for different uses for example the use of images on Webpages. The different file formats have their own characteristics such as file size, file compatibility, image quality etc. Compression techniques can also be very useful to know as you can make the size of an image smaller, however it is very important to know which technique affects the quality of the image and which one doesn’t.