Image compression

Image compression is a method where algorithm is used to compress the size of the file. Different software programs write different code and apply it in variety of manners. Therefore the way an JPG image is compressed in your camera is different from the way it is compressed in Photoshop. There are two ways of image compression Loss-less compression and Lossy compression.

Loss-less compression Loss-less compression lowers the size of the file somewhat with out having any effect on the quality of the image. The compression rate is on the other hand low. If quality is of importance it is best to use file type with this kind of compression. Its main flaw is the file-size. File format like Photoshops PSD TIF and RAW use this method

Lossy Compression Lossy Compression throws away information that it thinks is off no importance for ordinary people in its best form. Lossy compression has different levels of compression and as the compression gets more the more degradation you can see in the file. The main flaw in this format is that it throws out information each time the file is saved and in the end there is little left of the original. Gif, PNG and JPG use this kind of format. There is a huge difference in the file-size of these two ways of compression. A file that is 2MB saved in JPG format can be 16MB saved in RAW format. Same file in Tiff format can be 50MB in size, but little less in Tif compressed as LZW or in PSD format.

What to choose For Photographers there really is not so much to choose from if they want to think of the future. If they are taking images in raw format they should keep a copy of that. On the other hand after developing the file you will have to choose an other format as few if any offer a raw format as a developed format. There are therefor only two forms that have wide enough support from all computer-systems and software to be the formats for saving images. Those are .TIF and .JPG. Both have advantages and disadvantage. If on the other hand photographers like to gamble on the fact that some software houses like adobe and Corel will be here for ever they can go with files like. psd and cdr. The DNG format that Adobe has put forth could change all of this but that remains to be seen. read more in raw pipeline by Ted dillard