The idea of yarns having a pattern or a recipe has been on my mind for a while. The method I describe here is one I often use. Click on any picture to see it larger. (WARNING: this is a very picture heavy post.)
I start by taking commercially dyed merino roving and my drum carder. Using dyed roving is an easy way to play with color. To my way of thinking, making batts like this is all about getting a heathered yarn. To fill the bobbin on my wheel I usually need four batts. I often make each one a little different (convenient since it is easier to be inconsistent).
This yarn is based in red. I used two to three main colors (all versions of red) and several minor colors. I like the minor colors to be fairly well blended and the main colors to be a little less blended. To achieve this I blend the minor colors together with some of the main colors and then run that batt back through with the main colors.
These are the colors I used plus a violet that I used up. Some where used in very small amounts like the bright orange and the lighter pinks. The purples were only used in the purple batt and the dark burgundy is only in the two darkest batts.
I like to keep my hand just before the small roller to control the feed. Sometimes clumps of roving will try to fee through all at the same time. Light pressure on the feeding batt can reduce this tendency.
The picture to the left shows a length of burgundy that slipped through as a clump. It will not be distributed around the full circumference of the large drum. If I were to spin the batt like this, I would get strong streaks of burgundy. No problem, another pass through the drum carder will fix it.
For this yarn my four batts have the following minor colors: oranges, pinks, dark pinks, purples. It is okay to use colors from the opposite sides of the color wheel as long as they are in separate batts. They won't get blended enough during the spinning process to make an awkward color.
To prepare the fiber for spinning, I stack the batts unfolded. In this case I put the orange one on top and then the pinks from light to dark and purple on the bottom. I ruffled them here just to show you the colors.
I then stripped the batts lengthwise into half, then fourths, eighths, and sixteenths. Each sixteenth was then predrafted a bit (sometimes this is helpful because the batts get really fluffy and want to fall apart. Predrafting makes a more cohesive roving that can be wound into balls.
On to the spinning! I like to use the long draw with this preparation. I did the large skein that way and made a bulky two ply. I made three mini skeins to show you how changing the spinning method will give a different result.
The third swatch is spun over the fold. To spin from a batt over the fold, I split it lengthwise into eighths and then pull a staple length off the strip. With this method the fiber tends to draw from one batt at a time. You can see the the cast on edge is mostly the orange batt. The yarn will be less mottled and more stripey than if the long draw method is used.
For the final swatch I divided the batts and spun them individually into a fine singles which was then Navajo plied. I did just one color repeat; the colors could continue in this order or go from orange to purple to orange and back to purple.
As you can see there are a lot of options. You can pick the method hat will give you the effect you desire. There are also ways that I have not shown. For instance, on the last swatch I could have made a two ply with a barber pole effect.
(ETA: update with better pics)