Can someone explain this to me, I have already been told but just can't  seem to fully undestand how this works. I go to proof setup select custom, a box comes up, customize proof condition. top box is custom proof conditions with Custom selected from the dropdown list, next is device to simulate, adobe RGB (1998) is already selected in the dropdown list so do I go in and select the profile for the paper type which I am using or do I leave it as is, Preserve RGB numbers is unticked, do I leave this, Rendering intent is relative colorimetric which I usually choose in my print options, and the black point compensation box is unticked, do I leave this unchecked.

All my work is done in RGB and don't seem to have too much trouble , but when I download my wifes Images from her compact they are in Srgb and seem to get really crappy prints and can't work out how to overcome this problem.

Presuming you are inkjet printing you really should not be using the proof set up for something as simple as this, and if its a srgb or Adobe rgb profile should make no difference if you are setting your print with preveiw settings correctly by ticking the document box and choosing let photshop determine colors ,then selecting your printer profile from the profile box drop down menu and letting colour managment do its job properly.

 Hard proofing for Blurb books I now use their printer profile (which I have downloaded to PS) by going to View - Proof Set-Up and custom.  In the dropdown menu I find the profile and turn it on and also change the intent to Relative Colorimetric. Once I have done this I change to CMYK, blurbs printing method, and then turn on Gamut Warning.  This will grey out any colours that won't print true and I can tweak the image untill the out of gamut colours come into Gamut - as close as I can get them depending on the image of course.  Once that is done I put everything back to my original sRGB image without further editing (even if it looks a bit dull) and save it to my book file as I now know roughly what it will print like for the book.

 I used to do everything in aRGB but got fed up making sRGB copies for the web.  I now work totally in sRGB and never have a problem.  This explanation is my simple novice way of saying things by the way, so I hope it helps in some small way.