Go colors! Go Smitten! You can do it! I need to calm down!
ok. ahem. I really love me some pigments, utramarines, etc. The thing with those is that you have to mix with with either water or oil, depending on if they are water or oil soluble...I've wasted a lot when I wasn't sure which kind I had and it wouldn't mix! I have some neon pigments which are seriously awesome!
Remember, for any swirling make sure you are not using an fo that accelerates trace and that you are using a decent amount of water (ie a deep water discount makes swirling a PITA). I've had soap on a stick while attempting complicated swirls!
I just about always do swirl in the pot because it's easy and does a decent swirl, and my everyday molds are log molds. Get your colorants ready ahead of time. For most pigments, 1/4 tsp to 1/2 tsp per pound of oils is sufficient. I usually mix up a little more than I need in case I want a darker color.
So, for a 1 color swirl where you are not coloring the base soap and then adding a swirl of color do this: Go by the poundage of oils, for a 4 lb oil batch that you want to do just a little swirl, I would leave about 3/4 uncolored and color 1/4. So you are coloring roughly 1 lb,
1. mix up 1/2 tsp (that's the high end of coloring) with a 1-2 tablespoons of oil or distilled water, depending on what you have.
2. After you reach trace (not light trace, but where you are actually going to mold) remove about 1/4 of your soap to another container. I like plastic 2 cup spouted measuring cups. Pour in most of the mixed color, about 3/4 of what you mixed up. Stir well in the container. If it's the color you want, you are good to go, if it's too light add a little more color, too light add some uncolored raw soap. When it is well mixed, time to add it back to the pot.
3. Pour a thin stream around and around and criss-crossing into the pot. After you get it all in, stir once or not at all (seriously, you don't need to stir since half the swirling has been down already, and the rest will take place as you pour in the mold.)
4. Pour into your mold and it will swirl some more.
Easy peasy! Although I'm sure I made it much wordier than it needed to be, the main part is figuring out how much colorant you need for the amount of raw soap you are coloring. For 2 colors, color the soap in the pot before you add the swirl of another color. For a really pretty 3 color plus white swirl, remove 3 portions of soap (fairly small amounts, depending on batch size), leave the main portion in the pot uncolored, and color each of the 3 portions something different.
Now, for freakin' gorgeous awesome swirls, if you are using a slab mold (and believe me, it is really hard to get this to work in a log mold, if someone has great results that way I would love to hear it, 'cause I have failed miserably on many an occasion! The swirled part just can't reach all the way to the bottom of the mold, so you are left with bars that are swirled on one side. And, because of the way you cut a log mold, the swirl is on the side of the bar rather than on the "face" of it, like in a slab mold) you want to do a kind of "cheesecake" method swirl. Remove a smaller portion of your soap to color and pour the rest (maybe 60-75%, colored or not) into the slab mold. Color the portion to swirl and then pour into the mold in straight, parallel lines. Going the opposite direction (perpendicular to the soap), drag a plastic spoon handle, or something like that, through all the lines in one direction, then remove the spoon and drag through all the lines, beginning at the opposite side, in the other direction. Althernately pour your soap in a kind of back and forth motion in connected lines, and then swirl in a swirly motion that goes from side to side and then crosses back over itself. Yeah that's easy to understand :p
Here's a terrible pic. The "cheesecake" method is on the right, the swirly swirl is on the left. The lines of black are the poured soap, and the lines of red are the way you are dragging through the soap with the spoon handle. Notice the arrows.
I'm soaping this weekend, I will do picture tutes of both methods since I know that was confusing and probably not that helpful!