Hello there! I hope you’re staying warm — it’s been quite a cold and snowy winter here. I’ve been holed up away from the weather, so I figured it’s a great opportunity to get to know my colors! In my last post, I mentioned that I’m adding Indanthrone Blue (PB60) to my watercolor palette. So, I’m sharing some of my experiments here as I’m learning more about this color!
About Indanthrone Blue
Background
Indanthrone Blue, also known as Indanthrene Blue, Royal Blue, or other descriptive names depending on the brand, is a deep, dark blue. It is made with the pigment PB60, which was created as a vat-dye by Rene Bohn in 1901 (source: MFA Boston).
While most major brands have some form of PB60 in their line, I don’t often see this pigment in other artists’ palettes. As a deep blue, it’s regularly compared with indigo; a much cooler blue, indigo seems to be the more popular option.
I have several tubes of PB60 in my collection, so I decided to try each. As sometimes happens, each example has a slightly different hue. As the most neutral option, I used Daniel Smith’s Indanthrone Blue for the remaining tests — and it was my selection for my palette.
Properties
Regardless of brand, Indanthrone Blue is transparent, non-granulating, and highly staining. It glazes nicely, leaving a clear, strong mark on top of a previous layer. Due to its staining nature, it doesn’t lift completely. I wouldn’t recommend this for an application where one is lifting color. Similarly, Indanthrone blooms readily, but does not full push the pigment back from water droplets.
The Daniel Smith variant seems relatively stable when dropped wet-into-wet. It doesn’t spread too far from its drop-in point.
It’s worth noting that Indanthrone has a pretty significant drying shift. According to Handprint, some applications can change as much as 50%!
Why Did I Add This Color to My Palette?
Like many other artists, blue is the most common color in my palette. I currently have at least five or six blues, depending on how you regard lavender and teal! So, while I have always been intrigued by this color, I never paid it too much heed.
That is, until recently. Now, I need to make a confession — please, bear with me through this — I am not the biggest fan of Ultramarine, French or otherwise 😱. While I truly enjoy it in many mixes, I find it to be sensitive to dulling effects. The oversized granulating particles sometimes overwhelm my work. For these reasons, I dislike using Ultramarine in skies — but I end up adding it, to deepen the zenith.
So when I dropped into my sky deep-dive last month, I found myself reaching for Indanthrone to deepen my skies. I squeezed a dollop of paint onto my mixing space, as I usually do for one-off paints, and figured it would just live there for forever — as my palette is littered with dots from years of tests. Imagine my surprise when I hit the pan with my brush — and quickly squeezed out more and more! I realized I was using this color for so many applications beyond just skies: evergreens, shadows, anything that benefits from a deep blue.
Highly transparent and non-granulating, Indanthrone Blue can hold its own in a sea of other blues. As a warm blue, I often think of it in the same category as Ultramarine — but as illustrated by the image here, Ultramarine is much brighter (and of course, granulating). I thought of both Phthalo Blue (Red Shade) and Prussian Blue as possible competitors, but both are much brighter and more on the green side.
Before adopting this color, when I wanted a darker blue, I would add a touch of Burnt Sienna (or similar) to French Ultramarine. While a useful mix, this can rapidly lean to the gray side — and the granulation can leave an almost “dirty” effect to the mix. I’m pleased to now have a cleaner dark blue on my palette.
Indigo is another color that has been in and out of my palette for years, as my representative dark blue. This has its applications, but it isn’t an essential in my palette — especially when I have other cool dark colors, like Perylene Green. I pulled Indigo off my palette while in Spain, after an ill-fated night-painting adventure, that involved me accidentally creating a green sky — and I absolutely COVERED all the paints in my palette with liquid indigo. I actually just attempted to recover the painting from that night by placing a light wash of Indanthrone Blue over the sky — not too bad!
Color Mixes
As you might know if you’ve read my other posts, color mixing is my absolutely favorite thing to do. Naturally, I can’t resist mixing this with my color palette!
Here are some of my representative exploratory mixes:
Cobalt Blue
As I mentioned before, I like to deepen the zenith of my skies with a darker blue. Given my base sky color is invariably Cobalt Blue, this seems like a great mix to explore! While the range isn’t too great, given both colors are in the same family, I enjoy the soft colors that can be achieved with this mix. I believe this can approximate an Ultramarine as well — maybe there’s a future where I don’t have that on my palette!
Quinacridone Rose
As my main cool red, I couldn’t resist mixing Quinacridone Rose with this color. Ever pushy, Quinacridone Rose can easily overtake other colors; Indanthrone Blue is no different. When stirred, the two colors create dusky purples that are beautiful in shadows.
Winsor & Newton New Gamboge
I wanted to see what greens this color might make, and as landscapes are my most common subject, I chose my warm yellow — W&N New Gamboge — to mix with Indanthrone Blue. This mix was delightful to play with! The pair mixed well on the page, and created a range of mossy greens. From light olives to deep, almost Perylene Blacks, this mix is an incredibly versatile option.
Indian Red
I love mixing reds with Indanthrone Blue, thanks to the browns and blacks they create! Although Indian Red isn’t currently on my palette, this is one of my most favorite mixes! The two push each other and try to overtake each other, but regardless create lovely combinations. From brick reds to muted grays, this can be an incredible pair to include.
Complementary Colors
According to Handprint, Indanthrone’s complementary colors are Earth Yellows/Browns. While I haven’t yet fully explored these mixes, here are some quick combinations with some colors on my palette!
Well, what do you think about this color? Do you have Indanthrone Blue on your palette? Are there any mixes I should try? Leave a comment below!