As the skill at painting improves though, the differences diminish. In fact most skilled painters are quite comfortable at using brushes and would prefer them to pencils anytime. Watercolor pencils though are excellent painting aids to both newbie and pro. It is applied technology in the true sense of the word and its applications are still developing.
Watercolor pencils are similar to the effects made with watercolor in tubes except for minor differences in effects.
The finest line that you could define using watercolor pencil is applying a sharp point on a dry paper. Then you could control the lines by using the brush to redirect the lines according to the design, effects, and images that you have in mind. This is also where you get the most intense color. In comparison, the watercolor dry technique is the most intense color and lines that you will get out from tubes and pans although because of the thickness of the resulting lines, bronzing results.
When you dampen the watercolor paper before applying the watercolor pencil, the lines that results will be broader and softer. The wetter the surface that you paint the watercolor pencil on, the broader lines become.
Techniques at application
Scraping – You could scrape the color off the pencil mix it with water, adjust for temperaments, and use it as you would a regular watercolor. To create textures, you could scrape the color off the pencil directly into the paper and paint the scrapings over with water for textured effects.
Dry painting – watercolor pencils could produce rich detail. Use the pencils, as you would color pencils. Draw the details and shadings and leave other parts of the drawing untouched or touched barely by water. This could produce interesting variations in textures and colors that could not be produced by other watercolor painting techniques. If you do the painting on a moist surface, paint over a dry pencil to create other textures and details.
Typically, you could layer as much color as you desire. The danger only lies in muddying up the color that would result to poor color definition. If you should layer and would want to touch only the color that is in the topmost layer, brush very gently. Brushing the layers over and over would tend to mix all the colors layered over creating the same muddied effect.
Finally, keep the tips of the watercolor pencil clean and dry. Wipe the tip of the pencil after using to keep the colors pure. Before starting on another work, scribble the pencils first on a scrap of paper to remove whatever color left on its tip during the previous painting to insure that you get the color desired.