How to Make a JPG Image More Clearby Serm Murmson
JPEG files -- also known as JPG files -- use a large amount of compression. By definition, the compression process introduces a loss of colors or pixels. As a consequence, your JPEG images can appear distorted or blurry. In order to make a JPEG image as clear as possible, you must take some precautions while creating and saving the image. The loss of information due to JPEG compression is irreversible.
JPEG compression occurs within blocks of your image. Each block is 8-by-8 pixels. Within these blocks, the JPEG compression algorithm scans for important visual information such as the color and brightness contrasts that make up the borders between objects of your image. One of the processes by which this compression occurs is called "chroma subsampling," a process via which colors are simplified while brightness levels are preserved. Additional compression effects occur when the algorithm detects borders -- this often results in a ringing effect, whereby once-clear borders become fuzzier. This effect is usually more noticeable in images containing text. While it is computationally possible to trace the effects of ringing and partially restore border clarity, this function is not available in standard image-editing software. Instead, you must use a post-processing utility that employs special averaging processes to reduce ringing artifacts (see link in Resources).
To maximize the clarity of your image while still using the JPEG format, you should minimize the number of different colors you use. Reducing the overall color palette of your image can prevent the JPEG compression process from altering the colors of your image. For example, if you create a black and white image, the visual information in your image is binary in nature and therefore will suffer less reduction during compression.
If you have the ability to alter the nature of the shapes and designs in your image you should use as many simple borders and lines as possible. As shapes and lines become more complex, the risk of losing these nuances during compression increases. While ringing artifacts will still occur at high levels of compression, they may be less distracting if your original image shape is simple.
When you save a JPEG image, you typically have a number of choices of compression level. To make your image as clear as possible, use the lowest amount of JPEG compression first. If size is a concern, you may need to compromise the clarity of your image in order to meet these requirements. In general, you should save your JPEG image in a lossless image format such as PNG first. You can later open this file and save it using a number of different JPEG compression levels; by so doing you may find that you can achieve a high level of compression without sacrificing clarity.