I'm printing a high quality fine art project that combines text and pictures. My designer has done this via InDesign.
When I do test prints the quality of the images does not match Photoshop
They are less sharp; subtle but to my eye noticeable. The tonality also differs.
Will a Postscript RIP help the file to be as good as the image looks in Photoshop?
Will converting the IN file to an EPS be a better method?
My suspicion is the problem is in your print settings. Make sure you have "send image data" set to All.
But I would export to PDF/X-4 and print from Acrobat rather than printing direct from ID, myself.
No, never use any EPS anymore.
Are the images linked to the original file or have the files be copied and pasted into InDesign.
Take also care, that the links to the images are not broken.
Export a PDF/X-4 and print from Acrobat which has better performance with printing than InDesign.