Premo has a large color range. I’ve found that the colors in the photo above, plus black and white, should be all that are needed to mix any color.
The ultramarine and purple are really dark, but turn into recognizable colors when enough white is added. They offer a lighter purple, but it has mica powder in it.
Premo offers many other colors including metallic, glitter, fluorescent and stone.
All of these swatches were baked at the manufacturer’s recommended temperature in two aluminum baking tins, one inverted as a lid with two small ceramic tiles inside.
All of the colors were soft and sticky. White and translucent were firm. None were the least bit crumbly.
I had difficulty getting the raw clay swatches to keep their shape, remain flat and not stick to things. If I were working with Premo, I’d leach all the colors. I’ve found it’s possible to leach Premo too much, to the point where it no longer sticks together.
In the photo above, mixtures are indicated by lines drawn between colors.
In the top and bottom rows, I mixed colors that were visually halfway between the packaged colors in the second row. They weren’t mixed half and half because some colors are stronger than others.
The primaries of fuchsia, zinc yellow and turquoise mix quite well to make secondary colors, as shown in the top row of the photo above.
WHITE & TRANSLUCENT
White Premo stays nice and white, even when baked multiple times, though it does break. It can yellow or brown when baked at higher temperatures. See Baking Polymer Clay Without Yellowing or Cracking for my attempts to get Premo to not break by baking at higher temperatures.
Translucent white Premo starts out yellow and gets darker when baked. The more you bake it, the darker it gets. See How to Avoid Plaquing in Polymer Clay. There’s also a plain translucent (as opposed to translucent white) which is a bit darker yet.
COLORS THAT DARKENED WHEN BAKED
Colors that darkened noticeably when baked:
Colors that darkened a little when baked:
It’s hard to tell with purple and ultramarine because they start out so dark. The rest of the colors remained quite true.
COMPENSATING FOR COLOR SHIFTING
I compensated for color shifting by adding white or yellow. These came closer to the raw clay color, though some could use even more.
Yellow can be used with green because it already contains yellow. The photo above shows the green is less pastel-looking when mixed with yellow, but when baked, it didn’t lighten as much as when mixed with white.
Before I started compensating, I added a bit of white to ultramarine and purple, since they were so very dark. The circles of raw clay in the lower left corner include the extra white. Purple could use even more white.
I’ve heard of adding translucent, but translucent has its own set of challenges, as mentioned above.
Test these methods of compensating by baking small swatches before making a project.
NO BENEFIT TO DOUBLE-BAKING PREMO
There’s no real benefit to double-baking Premo as the colors shift about the same amount. Premo doesn’t seem to have much of a problem with plaquing. See Double-Baking to Avoid Plaquing in Polymer Clay.
Premo has a tendency to break and it doesn’t break any less when double-baked. Translucent Premo is much more flexible than white Premo.
Premo green, fuchsia and translucent darkened noticeably when baked. Purple and ultramarine darkened a little. Purple and ultramarine are very dark and really benefit from adding some white.
Color shifts can be corrected with a little white and/or yellow.
Translucent white starts out yellow and gets darker when baked. The more you bake it, the darker it gets. It didn’t seem to have a problem with plaquing.
Premo can be a soft, sticky clay. I’ve also had problems with it breaking. Translucent Premo is much more flexible than white Premo.
Official Premo site: http://www.sculpey.com/product/premo-sculpey/
P.S. I bought all these products myself and received nothing from the manufacturers.