I have only used raw since I discovered it years ago for that very reason one thing I wonder does just making a copy of a jpg to work on degrade the original I am pretty sure that flipping/rotating, and cropping probably does not degrade it, at least to anything that will be noticeable.
rmalarz wrote:
This is not going to be a "this format is better than...". It's simply going to clear up a few misconceptions bandied about on this forum regarding the jpg file format. In fact, it's only going to clear up one misconception about this file format. The jpg format is a lossy file format. This means it is going to lose data. An understanding of discrete cosine transforms would be helpful in understanding the process. However, suffice it to say, here's what this post is going to clear up.
If one opens a jpg file, looks at it, and closes it, nothing happens to the file.
If one opens a jpg file, looks at it, and saves it, it degrades.
This is just the nature of the jpg file format and the save algorithm. It's that simple. Open, Look, Close, nothing. Open, Look, Save, file changes.
Yes, one can edit a jpg. However, in addition to the edits one makes, the save process works just the same making additional changes to the file over which the photographer has no control. The only control the photographer has is how much more gets changed based on the amount of compression selected at the time of saving the file.
If you don't believe this, it's simple to prove. Using the diff function in UNIX, or the free Windows program windiff will show you the changes. Can you visually see them, perhaps yes, perhaps no. The changes are there none the less. Again, it requires nothing more than a Save to instigate a change to the file.
--Bob
This is not going to be a "this format is bet... (
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