May daughter purchased an IPF5100 and the prints were dark after profiling with an x-rite pulse. Custom profiles made by 2 venders did not help. When I posted on other forums most responses have blamed the monitor profile. When I purchased a 6100 in Oct. my prints were also dark. First profiled with x-rite pulse did not help. I worked out how to lighten before printing but did not fix problem. When pulse failed I purchased spider3elete and spider3print. Still had dark print. I soon realized when I compared pure colors and printed colors, the colors were the same color but printed patches were much darker. When I adjusted the brightness by + 12 before creating the profile (trial and error) I was able to get excellent match between screen and print. I have used test images from several sources to be sure it was not how I was processing the images..
When I applied this to my daughter’s 5100 printer, I get similar improvements.
It is my conclusion, after reading numerous posts on several forms that the IPF x100 series printers print significantly darker than the IPF x000 printers and that profiling does not help this problem. (Including custom profiles from reliable sources)
PS: I have had problems with numerous papers and paper settings, including canon papers using canon settings and have calibrated the printer colors several times to be sure the printer was calibrated.