The new Rembrandt specialty colors including interference, spark and chameleon glass glitter are available as a set from Dick Blick here.
You can also get the colors individually from Jackson's UK (they affordably and reliably ship to the USA) here:
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Further info will be added to the lightfast testing and art supply review section. This includes any other videos I've made about this company, still images of example art, a collection of color charts, along with fugitive fading results. I share my experience on hundreds of pigment and dye ingredients from dozens of painting, drawing and craft supply manufacturers.
If you would like to buy any of the supplies I used in this video, the Amazon links are below. As an Amazon Associate I earn from qualifying purchases. I've also included links to the waterproof inks, pens, brushes and papers I use in all of my reviews. For watercolor, gouache or ink painting, I use small round brushes by Princeton. Heritage series is ideal for a sharp point, small details and snap. Their Neptune series is a synthetic imitation squirrel hair, which is a very soft brush with an amazing ability to hold a lot of water for washes.
Happy painting :)