When I was at Art College in the early 1980’s I would get my hands slapped for using pure black out of a tube. We were told to mix our own black from reds and blues as it would harmonize better with the other colors in our paintings, and I agree with this theory and have taught it to many a student over the years. Pure black our teachers told us, is not a color, it is a black hole that sucks light in and does not reflect any light waves back out into the universe. As we were all listening to David Bowie’s Space Odyssey at the time and had grown up with lunar landings we could all relate to this far out concept and avoided black like it was the plague of the universe.
These days I work primarily in oil pastel and I find the black pastel to be very useful, in moderation. I don't blend it with other colors, I use it primarily as a defining line and it really makes all the other colors pop and vibrate - although I still feel as if I’m breaking some universal law for using it. George Shipperley http://www.georgeshipperley.com/#home, a well-known oil pastel artist uses black to great success and it was he who inspired me to break from my old art college doctrines and try something as outrageous as using pure black.
Many Master artists, like Rembrandt, Manet, Renoir and Cezanne to name a few, used pure black with great success. However, when pure black is in the hands of the beginner artist who has less of a feel and experience with color then it can become the demon that can sully other colors. This may have been the reason why our art instructors tried to keep pure black out of our young and inexperience hands.
Here is another blog post about the different black pigments, which you may find interesting by Canadian painter Robert Genn titled, Queen of color.
Artist Jane Wilcoxson was born and educated in England U.K. She now works from her home studio in Oswego Illinois, USA. and uses oil pastel to create contemporary fine art of quirky animals and fantastical scenes that uses color and playfulness to deliver the magic of the universe to everyday spaces. You can view Jane's work at http://www.JaneWilcoxson.com