Compression and Resolution

There are two different types of compression techniques are Lossless and Lossy. Lossless makes the image size smaller but it has a better image quality when it is compressed and never discards data. Lossless is used in many different applications such as ZIP file, PNG and BMP are all lossless formats this means that if you save an image as one of these formats that the quality of the image will stay the same. You should always save an image as Lossless to keep the image quality.

Lossy the image size will be smaller as it discards data, losses a lot of detail and the colour of the image changes. Lossy formats are the likes of JPEG and GIF which means that if you save an image as one of these formats the quality of the image will be lower than the original. When uploading an image to a website or on the internet it is better to use Lossy as the image size will be smaller but keep the original copy.

Depending on what types of file formats you save your images as the resolution will differ from each format. As you can see from the image below that the higher the resolution the more detail that is in the image and the clearer the image is. If you wanted to print out a photo you would use a file format like Tiff as it doesn't lose the quality of the image but will produce a larger file size. Resolution can be measured in many different ways such as lines per inch or lines per mm using the overall size of the image.

 

   

The colour depth also depends on the quality of the image as the more colours the image the clearer and smoother the image will look. There is a range of different colour options that you can choose from such as Monochrome, Greyscale, 256 colours, 16 Bit, 24 Bit and 32 Bit which is true colour which means that if an image has a 32 Bit colour the image will look more lifelike which then requires more storage space compared to a 16 Bit. As you can see from the image below the one on the left use more colour than the one on the right and it looks a lot clearer, so using a higher bit means a better quality of image.

Settings

When you are saving images you have to consider what you are going to do with it email, print or upload onto the web so you will have to have different settings for the different options. If you were going to send the images via email you will have to save the picture as a file format that doesn’t have a large storage space as emails have a limit to how big an attachment can be. Having a format that requires less space means that the image will lose some quality that’s why Jpeg is mostly used as they don’t take up much space and don’t lose much of the original image.

If you are planning on printing out the images then you want to use a TIFF format as it is considered to be the best format when printing as it keeps the quality of image even if it takes up more space.  Making the image smaller if you used TIFF would result in image quality being lost. When the image is printed out it is clear not blurry/pixelated and that it is at the highest quality.

If you are planning to upload images to the web you will have to choose a format that doesn't require a large save file so it will have to be small as if they are to big they will take longer to load when they are online. It will be better to use a PNG or JPEG format as they don’t require much space and that because they both are lossless when they are reduced in size they will still keep the same