PR101 is a multipersonality pigment that is typically used to create earth reds (e.g. Indian Red) or earth orange burnt sienna alternatives (e.g. Transparent Red Oxide), sometimes even earth violets (e.g. Caput Mortuum Violet). This paint by MaimeriBlu is the only time I’ve seen it used to create a straightahead brown. Of the typical three PR101 offerings, it is most similar to the earth violets, but it is different enough in palette role (a neutral brown/burnt umber alternative) that I decided to make it its own Color Spotlight entry.
Pigment Stats
Pigment Number: PR101
Names: Imidazolone Yellow (Holbein), Da Vinci Yellow (Da Vinci), Pure Yellow (Schmincke Horadam), Winsor Yellow (Winsor & Newton)
Chemical name: Synthetic anhydrous red iron oxide
Invented in: 19th century
Toxicity: Nontoxic
Lightfastness: ASTM I (Excellent)
Transparency: Varies; this one is opaque
Staining: Yes
Granulating: Varies; usually yes; this one yes
Experiment Results
Color Family: Earth Red
Hue/Gradient: Grades from a neutral to slightly reddish brown, very similar to Burnt Umber, to a pale dusty pink, similar hue to Potter’s Pink. Much less red than Indian Red (shown at the bottom). Hue reminds me a bit of reddish-brown Imidazolone Brown (PBr25), but granulating. Some of the granulation appears to be grayish, a slightly different hue than the pinker under-color. Tendency toward streakiness, like many granulating paints.
Transparency: Opaque
Color Mixes: Neutral brown is easily shifted toward earthy yellows, oranges, reds, or violet browns depending on mixes. With blues, makes a range of dark grays.
Comparison to Other PR101s
Mars Brown (far right) is much more neutral than the earth scarlet Indian Red, but has similar opaque properties. Mars Brown is more brown/neutral and less orange than Transparent Red Oxide, and is also not transparent.
My Review of MaimeriBlu Mars Brown (PR101)
I may just be a PR101 fanboy, but I really like this. I am not usually a fan of neutral browns and have never found a Burnt Umber that I liked, but I find this one enjoyable to use. Perhaps PR101 is just texturally nicer to me than PBr7; I find that PR101 is stronger, easier to rewet, and has less of a tendency toward hardness.
I find this to be a nice color for tree bark, especially in the Pacific Northwest, where I find that many types of bark do tend toward a pink undertone.