A workflow to produce neutral and toned printed images from black and white originals
There has always been a problem in printing black and white images with a four colour process like the HP Indigo printing machines of Blurb use. The grey tones are printed with four colours, so you may have the problems of a slight colour cast or some metamerism when viewing the images under different light sources.
How can we approximately achive pure neutral B&W prints and how can we emulate duotone prints with the four colour process? For monochrome images I recommend using toned images as it might be difficult to obtain a neutral gray image from a Four Colour Process printer. With a duotone or a toned image the colour might subtle shift from screen to print, but it will present far less of a problem than a slightly magenta or green tinted neutral grey would. Also a duotone will lend a pleasing dimensionality to your images.
This is a test book with 33 proofs of pure or toned black and white images with the Blurb ICC Profile and some other CMYK Profiles. There are different toning procedures used and described.
There is also a test page with different black backgrounds like Rich Black, Plain Black, Cool and Warm Black.
This book is also available for ProLine Uncoated Paper.