I just bought a complete set of "Inktense Color Pencils" from Derwendt. I did some tests with them to get familiar with what they do when dry or wet. The inktense pencils are water-soluble but when they dry are permanent. I found the colors to be vibrant + fantastic!
First I lay down a very pale wash about an inch long and 1/4 inch wide. (the wash I did was a 'dry wash', this is a term that means a light layer or drawing with a light touch to add a light layer.) Then I added, with a progressively heavier touch, more to the strip going left. You can see it's darker on the top left of each color swatch and lighter on the right. Then I used a 'waterbrush', that is a brush that holds it's own supply of water for field work, to pull down color from the top. As I got to the darkest area, on every single color I was amazed at just how brilliant and beautiful each color was! Even the browns, neutrals and mustard color were lovely!
I'm really not used to using water soluble color pencils but I will make an effort to use these till I get the hang of it. My intent is to use them in the field when hiking, to lay down washes that may be worked over with ink or color pencil. I did a catapillar drawing and colored it with them just today, check it out on my Nature Sketching Blog at : http://marymcandrew.blogspot.com/
Let me know if you have used the inktense pencils and what you thought of them.