Forum Moderators: phranque
I'm scanning photos at 72dpi, at maximum 300 x 200 pixels as web images. The images that come in over 20kb, I've opened in photoshop and tried everything I can think of to get the files smaller. The worst thing is, if I do a file - save as - jpeg - and choose and very low compression (even 1), the file size actually increases from the original, even though no changes whatsover have been made to the image! Short of actually making the image dimensions smaller (which I don't really want to do), is there anything else I can do.
You should definitely be able to shrink a 300x300 jpg to less than 20k w/o too much effort. I'd try another program if Photoshop isn't giving you what you want in this situation. Fireworks does a great job in shrinking graphics to web-ready status.
For JPG compression I only use Xat IO these days, as it always gets better compression and quality out of the same image.
If I compare my sites with others relying on Photoshop compression only, I usually am at 50% or smaller file sizes with sharpoer and clearer images...
PS, I have nothing to do with this program, but I simply still cannot believe that not all webmasters use it.
SN
1) If VueScan supports your scanner, buy it. The program is amazing at getting colours spot on.
[hamrick.com...]
2) Forget 72dpi, it's a myth. The best thing to do is scan at your scanners maximum capabilities then down size. This tutorial lays out the basics.
[tashian.com...]
3) Learn how to use levels and curves. They sound difficult at first but are actually fairly easy to understand.
Not all of what I listed above will reduce the final file size. What I'm saying (in a round about way) is in order to produce consistently good images with a light foot print you need to establish a set of steps.
Again, thanks everybody.
A couple tricks to get the file size down even more - before you save, take the image into L*a*b color space, select onyl the a channel, and do a very large Gaussian Blur (you can often get away with well over 3 pixels) Then do a similar blur on channel b. Now go back to RGB space and then Save for the Web.
If the GB causes colors to bleed at sharp color transitions, mask out those particular edges and just blur the rest of the image.
Those big, sweeping blurs help the compression algo by limiting the little color shifts that your eye can't see, but the algo still must cope with. And because you don't blur the L channel, you don't lose the detail.
