I switch my greyscale to duotone (adding a little warm or cool tone), then switch that to sRGB.

Until Blurb sorts out some technical issues, you may get inconsistent results on the black and white, twofold:

1. The inks are metameric.   It isn’t so evident in color printing, but it can be quite pronounced when viewing "black and white" books under different light sources.

2.  Also more evident in the monotone images are any variations in color from printing to printing.  My recent black and white books look very heavy on the magenta, whereas the same book printed more green before.  I suspect this is an issue with infrequent calibration on the printing side.

Nice to see some photos of the colour casting on a finished book.  It does indeed have a slight magenta hue, but as folk say – who knows if the ‘customer’ would notice on a finished album?  Thanks for clarifying the metameric process.

I wonder if adding a deliberate sepia tone (eg. via duotoning and converting to sRGB) would result in a less obviously casted alternative to more apparent b&w problems.  That way a more or less sepia image won’t look like a printing error (Though it’s not ideal either way).  Has anyone tried sepia toned images?

Barnaby 

I also was thinking of doing a sepia. My friend’s wedding book had just one grayscale photo that I had given her as Adobe RGB and it looked very neutral. I’m thinking that a magenta / greenish cast across a range of sepia images would not be nearly as noticeable as variations across a collection of neutral grays, although I’d rather not make the sepia too saturated or severe.