Re: O.K. were not GEEK's but need computer HELP

Posted by MarkPBG on Feb 22, 2013; 4:31am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/O-K-GEEK-s-Fer-HELP-NOW-TYPE-OF-INTERNET-CHOICES-To-house-tp4036578p4036946.html

JPG is a compression algorithm and the computations performed each time it is opened and closed innately add some variation in the final compressed render. The newer JPEG 2000 does away with this, but many online sites only support the older JPG format for linking.  Many sites will say this is a myth and is false, but think about it. JPEG is a non-lossless compression algorithm so each time you close the image, the algorithm is applied to an image that has already been compressed before. Over time, these miniscule differences in the way the image was saved degrade them. It takes thousands of these cycles to become noticeable, but it DOES happen. Any site claiming it doesn't just doesn't understand the way the compression works. It applies compression EVERY TIME THE IMAGE IS CLOSED. To save in RAW, the image must have been originally recorded in RAW, which is not done by all cameras.

Yes, just opening and closing them, they will be fine, but if you do any editing they can degrade even faster.

Even the article you quoted admitted that there is loss, but it is not normally detectable by the human eye. True, but after 1500-5000 cycles, it is, and if you make enlargements of the image to say, poster size prints, it becomes even more obvious to the human eye. I am an amateur photographer, I have sold work to galleries and have taken many classes on digital image printing and archiving. While MOST people won't notice....the FINE ART community certainly WILL.

Keep in mind, JPEG is acceptable in almost all everyday life, but if you exhibit your work, or make large prints, you WILL see its limitations. That being said, JPEG still offers the BEST image quality of almost all the lossy type compression methods.