Photoshop export + Blues turn to purple

Have you fixed it? I'm trying to resolve the same problem,

One additional thing comes to mind, though: is this a very noisy image - particularly with a lot of color noise? In that case you always need to compare at 100% view. Screen resampling algorithms could affect the result at other zoom ratios. The only way to take that out of the equation is to view at 100%.

Yes, but the monitor profile will use Relative Colorimetric intent in either case, hard clipping everything outside monitor gamut. There's no remapping (which otherwise tends to give a blue to purple shift).

So the color space of the document doesn't play a part here. Everything outside monitor gamut is hard clipped no matter where that clipping occurs, whether in the monitor profile or by profile conversions in the application. It's all invisible.

But ultimately, as long as you have two color managed applications, they should always be identical. The difference between them is in itself an indication that one of them isn't doing it correctly. They can't both be right.

Either Faststone's color management isn't properly set up, or the monitor profile is defective. Or Photoshop's color settings have been changed so that color management is disabled and/or the document profile isn't embedded.

In any case the colors here are very muted and should fit comfortably inside sRGB.

The monitor gamut is too small to view a full gamut Pro-Photo embedded image properly.  So there is clipping and interpolation that can occur when the image gamut is outside of the display gamut.

For example, if your monitor gamut was sRGB:

Or if your monitor gamut was Adobe 1998:

So regardless of the monitor gamut, there is a good portion of Pro-Photo RGB that is outside of the display gamut.  Whenever one image must be interpolated to be viewed it can easily be displayed slightly "different" than an image that is entirely inside the gamut of the display. 

Here's a full and complete color management troubleshooting checklist:

• does the file have an embedded document profile, and is it the right one?
• do you have a valid monitor profile - one that correctly describes the actual response of the monitor?
• is the application color managed, converting correctly from the first into the second?

This simple list covers all scenarios. Color management is a simple chain from document profile (source) to monitor profile (destination). In Photoshop everything will work out of the box at default settings - with one important exception: Export/Save For Web both have all color management disabled by default.

The description above has a lot of holes. Why was color management policies suddenly "off"? That indicates random experiments which is guaranteed to mess everything up. Has anything else been accidentally changed?

The prime suspect in these cases - assuming all applications have color management correctly configured and working - is always the monitor profile. A defective profile will often affect different applications differently. So the first troubleshooting step is always to rerun the calibrator, making sure all parameters are set to safe options. That basically means version 2 and matrix-based (not LUT).

Please set the Status Bar to »Document Profile« and post a screenshot of the original layered file and the jpg side by side (at the same magnification).

In the Export dialog, as well as in Save for web, make sure that both Convert to sRGB and Embed color profile are checked. You are probably viewing the image, with ProPhoto embedded, in an application without color management, which will result in wrong colors.

sRGB embedded is the safe choice.

When putting the jpg image next to the photoshop version there's a huge noticeable difference in tones.

In Photoshop?

Please set the Status Bar to »Document Profile« and post a screenshot of the two images side by side (at the same magnification).

Do you embed the profile when exporting the jpg?

What is the image’s bit depth?

What are your Edit > Color Settings?