I hope I can explain this clearly enough. Back when I was using the Ulead JPEG SmartSaver, my compression level was 75% of the original. This produced something small enough to post and download reasonably quickly without too much loss of quality. I'm a big detail person, so I'm very picky about that sort of thing. I used this setting for the books on my Golden Years site, ABPC, and then when posting here. When I could see that the SmartSaver program would not work on a 64-bit system, I knew I had to figure something out with Photoshop and get in the habit of using it before I got a new computer and was forced to do so. For all the many good things about the program, efficient web compression doesn't seem to be one of them. At least not that I've found in comparison to Ulead's compression.
There isn't a direct comparison between the two compression systems either. In Photoshop if you are using basic JPEG saving (File>Save or File>Save As), you have a quality setting between 1 and 12, not like Ulead's percentage. Photoshop's "Save for Web" command (File>Save for Web) is closer to Ulead's program in that it uses percentage compression, but compressing at 75% with Photoshop's "Save for Web" results in MUCH larger files than Ulead's JPEG SmartSaver. To match the file size I was getting from Ulead, I had to use the "Save for Web" command in Photoshop with a quality setting of "3" and set for "optimized" compression. The resulting image was a little more degraded than with the SmartSaver, but it was acceptable at the time to keep from uploading books here that were too large in comparison to what everyone else was doing. Since I started using this new compression system, and have drifted away and come back here several times, people have started uploading larger files. Using a quality setting of "30" now seems to produce scans of comparable size to what others are doing and artifacting is either gone, or greatly reduced.
As for re-compressing and upgrading the older scans, it doesn't take long at all to do. Just a few minutes actually, and it's much easier than the old way with the SmartSaver. I just have to open all of the files in Photoshop, run the automated action on all of the open files (which then saves them to a folder I use as a staging area of sorts for uploading here). Then I just zip them up along with the text file and upload. Very easy. I was mostly worried about it being work for you having to replace all of those old scans. In addition, there are also many that I down-converted to 150 dpi that need upgrading. I really need to look at my old uploads and see what I have better scans of readily available. I'll wait until next week to start work on them so I don't bog you down and also so that they don't distract from the anniversary books that will be going up.
-Eric
