In theory the blender helps blend colors together by wetting the surface of paper. In practice, colors will blend in any case (except with black) but will do so more smoothly on a reasonably wet layer of color. I have probably not mastered it as I find it’s more of a smudger than it is a blender, giving edges fuzziness, even on non-bleed paper.
To test the grey series I went for a dragon that adorned an Alfons Mucha poster of 1896 for the Lorenzaccio play:
I sketched the outline:
I marked the outline using Uni-ball pin pens (0.05, 0.1, 0.2 and 0.5 mm):
Then I applied layers of grey. I had to use a white ink Posca pen to cover some overlapping black lines in the moustache. Here is the finished version:
I learned that the alcohol ink smears pencil lines and even the Uni-ball pin pens ink, so it’s better to go easy on the outline and add those or add finishing lines afterwards.