Am currently shooting all new work in Prophoto. My old work is in Adobe. I calibrate my printer with a Spyder.
1) Can I use the same profiles with both color spaces since the emphasis (in the print dialog) seems to be on the rendering intent?
2) When I soft proof an orange sunset image it looks orange as it has for the entire time I am using it. When I open the same image and convert and save it off into Prophoto it now soft proofs as a blue/purple sky. Any thought? Seems I will have to keep one output workflow for each color space.
3) Have not installed yet, but have just unpacked an Epson 4880. With all the new technology I read about, is calibrating the printer as important as it was?
I've not heard of calibrating a printer with a Spyder - one usually calibrates and profiles a display with a Spyder - is there something new here I'm not aware of?
The printer profile performs a separate role from the display profile. This question comes up over and over again and has been addressed a number of times in these forums. I recommend reading previous topics to get more insight into this, or better still, buy Michael and Jeff's "Camera to Print" tutorial where the whole colour management process is laid out so clearly from A to Z.
In a nutshell, some colours can be affected by a change of colour working space but a change from orange to blue sounds highly unusual and not something that a change in colour working space would cause. This change can affect the saturation of the same colours but not not usually such a radical hue shift.
Calibrating and profiling your printer for each paper you use remains as important as it always was. It is essential to make sure that your soft proof is set-up for the specific printer/paper profile you will use for printing, to make sure that you have selected that same paper in the printer dialogue, to make sure the rendering intent is the same in the soft proof as it is in the printer settings dialogue, to make sure that you have "Photoshop Mananges Color" turned on in the Photoshop print dialogue and "Printer Manages Color" turned off in the printer driver. Also enable Black Point Compensation wherever it is offered. In soft proof I also enable "Simulate Paper Color" because I find it provides a more reliable soft proof, but there other respectable people who don't agree with me on that last point. It's more noticeable for some papers than others.
I suggest you make sure all of this is in order, and then compare your softproof between colour working spaces. You should not see enormous differences between ProPhoto and Adob RGB(98) on your display, except that saturation of reds is the usual issue expanding the colour working space. You can control that in Photoshop under soft-proofing.