Ok I think there's some confusion about how the edit in process and the colour spaces work.
Start with "Edit in CS"
Lightroom uses the Adobe CameraRAW engine. The same one as Photoshop. If you update Lightroom but not CameraRAW then you end up with an error. You'll also notice that Lightroom and CameraRAW have the same version release cycle.
Anyway when you click "Edit in CS" what it actually does is open it in CameraRAW with all the settings from Lghtroom, and then imports it into Photoshop. There is no loss in colour here, photoshop is opening the original RAW. When you save in Photoshop Lightroom will import the saved file. This is now different. It is no longer a RAW. It is an image file like any other with an embedded colour space.
Colour spaces:
These define the chroma point of the Red Green Blue primaries. I.e. just how red is RGB(255,0,0). The larger the colour space the more possible ranges of colours you can edit. However this is just the background to a very large problem. Colour spaces determine a way to get each pixel back to a standard space, a second colour space is then used to display the image.
In the case of Photoshop it will use the "working space" of the image to read the file, and the "monitor" profile to output it. Lightroom does the same for normal images. But for RAWs it will use MelissaRGB (a linearised ProPhotoRGB space) for the "working space" which handles RAW files much nicer in terms of calculations.
A non colour managed program will assume everything is sRGB input and output and do not conversions. It will take the bit value of the image and pass it to the video card. An input colour managed (don't think this is the correct term) application like Windows Picture and Fax Viewer will read the "working space" out of the file and convert to sRGB always.
Now this leads to a couple problems:
- Wide colour spaces need more data. If you're editing anything larger than sRGB in 8bits then you're asking for trouble. 8bits just covers the possible combinations in sRGB. Increase the colour space and you end up with posterisation, non smooth gradients, sudden jumps in colour etc.
- There's a finite number of colours that are recorded. Lets assume that you don't photograph LEDs or Lasers or any other single point source type light sources that would actually fall on the very edge of the CIE1931 diagram (i.e. a pure colour). Most images would fall neatly into sRGB, a few fall outside fit just fine into AdobeRGB. A few exceptions are some of those nuclear coloured sunsets. They benefit from the widest colour space but only if you're in support of the next problem:
- How do you display the colours. Nearly ever very web browser will assume an image is sRGB. That's the end. If you don't print your photos then turn off colour management right now. Set everything to sRGB and don't bother your head with it again because you gain nothing. Now lets assume you print, if you print at a nice pro lab who knows their stuff and actually supports colour management (i.e. will tell you they want AdobeRGB files) then your limitation is the paper. Matte paper will fit nicely into sRGB except for some of the greens which fit into AdobeRGB.
Overall I see no real point in using ProPhotoRGB. You can't view it, you can't print it, and it actually contains literally imaginary colours. So if you get a professional print done and you have a real need for it then and only then do you actually end up with a decent result and then AdobeRGB will probably still cover all of your needs.
Finally on the subject of your contrasty images which look the same. What you need to do is softproof. You need to get the profile of your printer and enable softproofing in photoshop. What this does is convert your working profile to the printing profile, and then back to the monitor profile and if you check gamut warning it will show you exactly which pixels in your original image can't be displayed in the colour profile of your printer.
So here's what I suggest:
Read over
http://homepage.mac.com/ilyons/pdf/ps6_sp.pdf.
Open your image you want to print in AdobeRGB, soft proof to sRGB and turn on the gamut warning. If nothing highlights then there is no point in using AdobeRGB for that image.
Then soft proof to your printer profile and edit away till you think it looks right, and finally send them the file. See if that fixes your contrast issues.
Btw just because you send someone a file doesn't mean they won't tamper with it. Like increase the contrast to make it "look better"
