Digital BW, The Print

I posted a similar question to this on the QTR forum

I have printed off the 21step.tif using QTR_1400_UT14_IGFS_cool and a blend of QTR_1400_UT14_IGFS_warm and QTR_1400_UT14_IGFS_cool (75% cool and 25% warm and) and find bronzing on the black end of the step wedge. This is only on the 100% patch and only seems to be noticeable in daylight. None of the other patches are affected and it isn't noticeable when viewed in artificial (incandescent) light.

I also did the same using the same profiles with Epson Premium Semi Gloss paper, with the same result.

When using Epson Premium Semi Gloss paper with the Epson 1290 and the 1290 profiles with UT2 inks there was no bronzing - alas the 1290 "gave up the ghost" and is no more.

Is there a satisfactory explanation for this and/or

1. Could UT2 inks be used with the Epson 1400.
2. Is it possible to use Epson Premium Semi Gloss paper with UT14
   inks or is there some incompatibility between ink and paper 

I favour the Epson Premium Semi Gloss paper as it is a brighter white - the Ilford Gold Silk is a creamier paper.