Adding a bit to what Andrew said, LR uses a colour space akin to ProPhoto with which you do your image edits while in LR. The program is designed so that you do not need to worry about what profile is embedded in the image as long as you are working it within Lightroom (This is laid out in Martin Evening's excellent book on LR2.) As Andrew said, you cannot softproof in LR. (We all hope this limitation will be changed in a future program upgrade.) On exporting the file to Photoshop, where it can be soft-proofed, you do have options regarding colour space and bit depth. Whether you print at home directly from LR or send the image to a lab just after exporting it from LR, you still have no control over the appearance of the printed image. If you want to have that control, which it seems you do, you need to do your finishing luminosity and colour adjustments in Photoshop with Softproof active. For doing the adjustments under softproof, you would need to tell the softproof which printer profile it should simulate. The ICC profile you would need in this case must come from the lab, if they have one they can share with you. The lab should tell you HOW they want the image delivered (i.e. with or without an embedded profile - they may for example just specify sRGB colour space) and they should give you their printer profile if possible, which you would install in your profiles folder so that you can call it up in Softproof, and adjust your image accordingly. For any of this to work as expected, of course your display also needs to be calibrated and profiled so that it accurately reproduces the file numbers as you make your adjustments under softproof.