I used to use pencil crayons all the time and would use lots of hard layers to get it all as smooth as possible. I kind of regret it, actually, because I'm sure it did damage to my fingers pressing that hard. Plus, the smoother I got the surface, the more waxy buildup that appeared after a while. The wax just rises to the surface and leaves an icky wax skin on top.
If you want to be daring, I'll second Raerae's suggestion to use rubbing alcohol afterward. I once dipped a q-tip in and rubbed the surface with it and it really spread the colour around. But it does sort of soak through and I'm sure there is some archival issues involved.
You might look into soft chalk or pastel colored pencils I've started to see around.
Usually I just work on colored paper to give an overall tone to my picture. I've never been much one for burnishing. You can also lay a 'base coat' of colored pencil underneath and lay down a light wash of alcohol over the pigment...it works somewhat akin to watercolor pencils.
I see that blending is coming up a lot, and if you don't want to go out and buy expensive blending pens/markers/pencils, using an unsharp white crayola works fairly well. It may not work for large white spots, though. Maybe you should try be very careful when you colour and make sure there are no gaps?
as others have stated when doing color you want to wax on wax off young grasshopper excuse my nerdyness for the karate kid ref lol but yeah small circles blends in the pits because the color pigment makes it thicker than what a ordinary pencil is.
Try filling in color using tiny circles instead of straight lines. Also, getting a colorless blender, either a marker or pencil kind, will help push pigment into the crevices. Burnishing helps too, especially if you burnish with a color that's slightly lighter than your base color. What brand do you use?
You can also use turpenoid & a brush to get the same effect as the color marker- same principle- it's solvent breaking down the binder...you get a little bit of a wash that fills the holes. The danger is- if the color is already heavily applied...the solvent will break the binder down- you risk pushing color around- like there was a fine layer of mud on your work. I use the turpenoid technique a lot...I've had success & plenty of "oh shit" moments.
You can get more solid colour by grinding the pigment into the gaps (burnishing, as someone else already pointed out). But every medium and tool that you use has a certain nature and you are only going to get so far in fighting that nature. If you OMG totally absolutely holy crap need perfectly smooth colour, just go and get markers or paints or a digital program or something. I mean, you can pound nails in with the end of a screwdriver and complain the whole time, or you can go out and get a hammer.
HUm I personally don't understand about colour pencils but I understand about photoshop. If you use photoshop, after scaning your work, you can use Topaz filter, it's a filter out from photoshop, I mean, it's like a nother program but you can easily... if you know what I mean... xD Just make sure you didn't let many blank spaces in your paper work and that filter will work amazing. It works really really well with sketches to clean up the lines.
I also remember having a white pencil, it had a very big tip which didn't paint any colour and I remember my Grandfather who paints, told me it was some sort of blender for pencils, what I don't remember is it was exactly for coloured pencils. I hope it helps!
Like most would say, you can get a colorless blender or a stump/tortillion.
But in my case, I just use the lighter color as a 'blender'. If you want to color something green, color it and blend it with the lightest green you have. Prismacolor, by my experience, is really smooth and blends well.Sorry if I wan't helpful. =_=
You can avoid the scratchy look by shading in tiny circles instead of lines. Color pencils will always have tiny white gaps, unless you're pressing really hard and burnishing. For burnishing you can use a white pencil, or a special "blending" pencil, or other type of tools. Read more here: [link]
Somtimes it's just the nature of the beast, too, kinda like how it is with graphite or charcoal. Since it's not wet like ink, paint, or marker, it won't always fill in everything. Even in that fox picture, you can still tell it's pencil. A few examples:
However, there are ways to blend out pencils to some degree. You can get a colorless blender (either a marker type or a pencil type works), you can use your finger or a tissue... I'm not that great with colored pencils though so I don't really know other tips.