sRGBs4w
Ever launch Save For Web and the colors in your image suddenly look terrible?
Original Image (ProPhoto RGB)
Image in Save For Web
So, what the heck is going on? Save For Web is expecting the image to be converted to sRGB. If we convert the profile to sRGB and a relaunch Save For Web, this is what we get:
Image in Save For Web (sRGB)
Hmm. Still doesn't look the same as the original. Easy enough to fix, just change the preview menu option to "Use Document Color Profile":
Preview Menu in Save for Web dialog
If you save out the JPEG from Save For Web and re-open it in Photoshop and compare it to the original image, you'll see it looks the same:
Comparing the JPEG from Save For Web and the Original Image
To solve this problem, I've created a script that will convert the profile to sRGB, launch Save For Web and then reset the color profile after you exit Save For Web.
You can assign a keyboard shortcut to the script once you install it in Photoshop. One note of caution, if you try to assign Save For Web's default keyboard short Command+Option+Shift+S (Mac) or Control+Alt+Shift+S (Win), you'll run into problems. The "Option/Alt" key is used to force debug a script in the Extend Script Tool Kit.
I've had a few people ask if the Scripts Event Manager is a good solution to change a docs profile to sRGB for Save For Web. The short answer is 'No.'
Here's the long answer:
The Script Event Manager in Photoshop post-processes the event. Don't take my word for it, try it for yourself. Run an alert script like hello.jsx with the Script Event Manager. It will play after the event. FWIW - I've put in a feature request to have the option to pre-process or post-process events.