This time, I played around with Blockx's Lemon Yellow, Blockx Red and Cobalt Blue.
The Lemon Yellow from Blockx is PY184, which according to handprint.com is Bismuth Yellow. This Lemon Yellow or Bismuth Yellow is semi-opaque. When used to mix with other colours, causes the mix to be opaque as well.
Blockx Red uses PR254, which according to handprint.com is supposed to be Pyrrole Red. But Blockx's Pyrrole Red is PR255. This is an intense warm red that can produce an orange even when mixed with a cool yellow like Lemon Yellow.
Cobalt Blue uses PB28. The colour is quite similar to Ultramarine.
The purples possible from this limited palette is slightly muted but still recognisable. It's actually a purple that can be used easily because it's already toned down.
Greens are not very vibrant. I was expecting to get some sort of Sap Green but the result is muted version of Phthalo Green.
The grays that can be mixed from these three primary colours are beautiful. For blacks, you'll need to use a lot of reds and blue, especially blue, so be prepared to use up the blue fast.
Here's the sketch that I painted with these three colours. It was a cloudy day so the colours are muted and this palette works really well.
Cobalt Blue has lovely granulation, just like Ultramarine.
The greens are kinda muted. Red was added to make the darker shades.
You can get vibrant oranges and peach-like colours.
I love the grays you can get with these three colours.
The paper I've used is from the Strathmore Watercolour Visual Journal.