I love working with colored pencils! I feel however, that the fact that some colors are not lightfast (Colors will stay true for 100+ years) diminishes the integrity of this medium. Here are some of my thoughts and my solutions for this problem..
The Colored Pencil Society of America puts out a Lightfastness Test Result Handbook. My latest copy is Version 6. My observations are that the main colors that are not rated highly are the portrait and pink colors. I use Prismacolor and Derwent Coloursoft pencils almost exclusively. Some of the ones that don't make the lightfast list are Prismacolor clay rose, Tuscan red and deco pink (discontinued but still available through Ann Kullberg's colored pencil website). I originally learned to create colored pencil portraits from Ann Kullberg's books and I don't think I could create a portrait or a still life without Tuscan red and deco pink. I have found that Derwent Coloursoft has an almost exact match to deco pink called 190 pink. This is the reason that I own an entire set of Derwent Coloursoft pencils because I liked this pencil so much. However, this pink doesn't pass the lightfast test either. Nor does their Blush Pink.
Prismacolor put out a new line of lightfast pencils which has since been discontinued. This set had some beautiful colors that are wonderful for portraits. Terra Rose is my favorite! When the recession hit someone wrote a comment in the CPSA To The Point magazine, that we artists should go out and buy all of these lightfast pencils to let them know that this is what we want and then they wouldn't discontinue them. I feel that most of their pencils were already lightfast and they repackaged them at a higher price. I SINCERELY hope that the new colors that they introduced will be reintroduced. I stocked up on my favorites so I am good for awhile but, I've found that many of those colors are my main stays.
Since I cannot create a colored pencil painting without using some of these "fugitive" colors, I have looked for other ways to retain the quality of my work. I have found the UV spray varnishes work well. I use Prismacolor final fixative when I finish a painting to prevent wax bloom. This (I read from an artist) is the only fixative that prevents wax bloom on heavily burnished blacks. I then use Golden UV varnish. I prefer matte or satin. I have read that others do a better job because of little particles of white that land on your painting when spraying. I found that spraying my painting when the painting is vertical alleviates that problem.
Most of my research comes from one lone artist in the boonies of Wyoming. I would very much like feed back about other artist's thoughts.
Visit my website at www.EileenNistler.com