Since I don't know what "Blurb" is, I'm going to assume that's your printing service somewhere, and that they have provided you with their target printer profile.
What you describe under current method is absolutely normal, expected behavior. Adobe RGB simply is a much larger color space than whatever this Blurb profile is.
If you care to let me know how or where I can get a hold of this Blurb profile, I can in a matter of seconds prepare an illustration of how the two profiles compare to each other. From where I sit, it would appear you're throwing away a lot of image quality by using Blurb.
There are two wacky ways of getting around your seeing the out of gamut warnings. The first is not to soft-proof at all. (Duh! ) The other one is an unorthodox workflow which works just fine PROVIDED you are aware that the image files as an end product are only good for Blurb and for no other purpose, and that is to set your WORKING COLOR SPACE from the get go to the Blurb profile. Of course that is not the recommended or even kosher workflow. It is only a workaround to the deficiencies of this Blurb profile.
I cannot comment on your "second method" until I know more about this Blurb phenomenon. If they print on a CMYK press, then they are throwing away a lot of colors, even if you send them images in sRGB. Nothing you can do about that.
The one thing I can say is that if the outfit doing the printing is the one that sent you the profile, then they will know how to deal with an sRGB file. The profile they sent you is just what their printing process uses. No need to attach a copy of their own profile.
OK, found the Blurb commercial site and downloaded the Blurb Profile.
It is indeed a CMYK profile, which means you'll have an abundace of out-of-gamut profiles if you profile any RGB file with that profile.
It's just the nature of the beast. CMYK spaces are much narrower than RGB color spaces. Even the lowly sRGB will be wider than this Blurb thing.
My advice would be to convert your files to the CMYK Blurb output profile before sending them out.
Thank you for this answer, it helps a lot.
Now i know what i must do and what i can do and expect.
You're very welcome.
I just did a few tests.
Blurb works with a CMYK profile and this is much smaller as RGB.
I found another printing service and this one works with sRGB, better result with Soft Proofing and the out of Gamut Colors.
I can convert them before sending them out without los of color and see the color result before printing.
Well done, Mario.
Sorry to tell you that the profile Blurb provides isn't used for the actual printing of the books so it's highly questionable how useful if any, soft proofing with that profile becomes. You have no control over the rendering intent used at print time too, what do you setup for the soft proof? The profile is more a 'feel good' option than anything else. Each paper needs it's own profile, how can Blurb supply one? Soft proofing with a profile that isn't used to convert the data that is printed is kind of useless!
Out Of Gamut (OOG) overlays in both Photoshop and Lightroom are not accurate (a kind way of saying it's buggy). You'll see OOG overlay in images that should show none. Further. The profile (the correct profile) will handle al OOG mapping far better than we can manually. Pick the rendering intent you desire based on a good soft proof, again using the actual ICC profile based on how you prefer the rendering. Profiles know nothing about colors in context. The OOG option treats a color that's a tiny but OOG and one way out the same; with an ugly overlay. Best to ignore it. Examples of why: http://digitaldog.net/files/LR4_softproof2.mov
Well, Mario, you couldn't possibly ask for a more authoritative source Than Andrew Rodney.
Thank you Andrew !
This is an eyeopener !