Digital BW, The Print

I printed 2 pics today w. the R800: one B&W using black ink only, and one 
color, both on Premium SemiGloss.   As to the black-only grayscale print -- I'm 
a bit perplexed.  When I printed black only on the 2200, I found that the prints 
had a strong warm brownish tone.  This print doesn't look like that at all -- it 
does have a tone that is not "neutral", but it tends toward purple, not brown, 
and isn't displeasing.  It looks, in terms of tone, like a fairly heavily toned 
selenium print, but not so heavily toned that you look at it and say it's purple. I 
can't remember if the black-only prints I did on the 2200 were with the matte 
black or photo black, so that might account for the difference.  Does anyone 
have a black-only print using photo black ink handy, and can you comment on 
the tone?

 In terms of image quality w. black only, no complaints -- I don't see any dots in 
the highlights and the image is nice and sharp.  Admittedly, it wasn't an image 
that had a wide swatch of sky or anything.  I guess this finding isn't surprising, 
given the R800's small droplet size.