Cerulean, meaning “sky”, is a light sky blue, traditionally made from the PB35 or PB36 pigments, which are both cobalt oxides. It’s an opaque, granulating, light-valued, green-toned blue.
Warning: Be careful to look at pigment numbers. Some brands, like Mission Gold, call their PB15 Phthalo Blue “Cerulean.” Don’t make the mistake I did when I first started painting, and get “Cerulean Hue” (from Da Vinci, Cotman, etc.), made from Phthalo Blue + white. PB15 is not the same color, and will not have the same granulation/magic/mixing properties.
Experiment Results
Gradient: A highly granulating gradient between a middle green-blue, to a pale sky blue. Doesn’t get very dark.
Opacity: Semi-opaque. This is the most opaque color in my palette (and it’s still not THAT opaque).
Glazing: Glazes to medium cornflower blue.
Lifting: Back when I only knew about wet-paint lifting, I didn’t really understand why Cerulean was considered an especially liftable paint. If anything, it lifts less cleanly than a Phthalo and makes less realistic cloud shapes. But when you do a dry-paint lift (scrubbing with a wet paper towel on dried paint), WOW, I See It. It’s like erasing a pencil mark, quick, easy, and gets completely white as if I never painted there at all!
Comparison to Other Brands
Daniel Smith – Cerulean Blue Chromium
Daniel Smith offers a Cerulean (similar to Da Vinci’s offering) as well as a darker, greener, more granulating Cerulean Blue Chromium.
I find the CBC is more interesting as a mixer but less suitable to skies.
Color Mixes
I found the color mixes for Cerulean to be surprising and lovely!
Lemon Yellow (PY175)
Range of granulating teals, mints, and yellow-greens. I especially like the cool mint foliage color (similar to Cobalt Green). I found it difficult to keep the lemon from overwhelming the blue.
Monte Amiata Natural Sienna (PBr7)
I was expecting either green or gray and didn’t get either – it’s staunchly simultaneously tan and blue! The balanced mix, with its granulation that looks like reflected light, gives me the impression of looking through clear water to the sandy bottom of the pond.
Transparent Red Oxide (PR101)
Love the clean brown and the medium brownish-tannish-blueish grays, perfect for rocks. A tiny touch of TRO in mostly blue gives a nice gray cloudy cast to the sky color.
Naphthol Scarlet
You can make an interesting Perylene Violet -ish hue from this combo, or soft gray-violets that look good in clouds.
Deep Scarlet
Nearly complementary, though a bit on the purple side; resulting in a range of soft violet grays, brick reds and slate blues. More muted than the Napthol Scarlet mix; similar to the mix with Perylene Maroon.
Indian Red (PR101)
This is one of the most even/neutral gray mixes I have found. I really like the lovely gray that can be made here, which turns either toward a violet-brown or a slate blue depending on the balance. I like these earthy granulating grays for mountains and rocks. It is ideal for a mid-value gray, as it doesn’t get dark/black like the Ultramarine + Transparent Red Oxide mix.
Quin Coral (PR209)
Potter’s Pink (PR233)
A super-separated, granulating purple-cloud sky mix.
Alizarin Crimson Quinacridone
I actually like this better as a sunset cloud mix than PP; it’s still granulating because of the Cerulean, but not as wildly so because ACQ is non-granulating, with a nice purple that is bold but not over-the-top.
Perylene Violet
This is also a cloudy-sky mix for me, but much darker and stormier. Still like ACQ the best.
Phthalo Green Blue Shade (PG7)
Bright, pretty turquoises and sky blues with cerulean granulation floating over the green.
Serpentine (Primatek)
There’s something so interesting about these greens and blues that don’t quite ever mix. It’s turquoise but a much duller shade than, say, Cobalt Turquoise. If I’m being uncharitable it looks like pond scum.
Lightfastness
I tested Da Vinci Cerulean Blue Genuine.
After six month of light exposure, the left (exposed) swatch is infinitesimally warmer (more violet-toned/less green-toned) than the protected swatch, noticeable only in tints. It’s extremely hard to tell. I would generally give this an A grade.
What Others Say
There are a number of other blue and turquoise blues made from PB36. I like this one, mixed with Ultramarine, for blue skies anywhere in the world. It is granulating and liftable, which is very important when doing skies so you can lift out the clouds.
Jane Blundell, Cool Blues
Cerulean is lovely for winter skies, providing a nice cool touch to the horizon. It creates delicate foliage greens, gorgeous rock pools, rivers, lakes. Beautifully cool and refreshing. The textural effects it gives makes it a great choice for soil, foreground, bark.
Debi Riley, Dive Into the Mysteries of Blue (2015)
The cobalt cerulean and turquoise pigments are a definite preference among some artists, who rely on them to temper warm mixtures and create subtly textured pale blue washes (cerulean skies really are unique). … Cerulean blue is an excellent palette complement to ultramarine blue.
SUBSTITUTIONS. All the cobalt cerulean/turquoise paints are relatively dull, and therefore are fairly easy to approximate with a mixture of cobalt blue with cobalt teal blue (PG50), or ultramarine blue with phthalocyanine green BS (PG7). See also the section on cobalt pigments.
Bruce MacEvoy, handprint.com (2010)
My Overall Review
I have to say Cerulean Blue is one of the most popular pigments that I didn’t get – at least, not at first. Everyone always talks about it as a sky color, but I don’t usually prefer granulating skies. You can lift clouds with it, but I don’t do a lot of lifting. I don’t find the hue to be particularly sky-like, at least, certainly not more so than a mix of Ultramarine and Phthalo Blues; most unmixed Cerulean Blues are, in my opinion, too green and dull to really approximate the sky.
What I didn’t realize is that there’s another side to Cerulean Blue: in addition to being a sky color, it’s a lovely granulating mixer that makes textured silvery foliage greens (with yellows), cool browns (with warm earth tones), and interesting grays (with scarlets/earth reds). I think it was important for me to wait to try this until I liked granulation, but once I did: wow! I love nearly every mix I made with it.
I am still continually disappointed when I try to use it in skies.
On my palette? Not on my main palette, but on my B-team and several of my theme palettes. I find that when it’s on my main, I consistently overuse it for situations where another blue would be better. I like to be intentional about it.
Favorite Version: Da Vinci Cerulean Blue Genuine, by far. I find it the most useful as I like its bright skies as well as its gently granulating mixes. DS Cerulean Blue Chromium is an interesting “special effects” paint when you want a ton of granulation in your mix, but it doubles down on the things I dislike about Cerulean Blue, i.e. being weak, muted and greenish.
Nontoxic Alternatives: Holbein Horizon Blue is a fairly nice pastel mix of white, phthalo blue and phthalo green that is a solid and pretty, good for sky horizons, but does not have Cerulean’s mixing qualities. Manganese Blue Genuine (PB15) is a (usually) granulating cyan made from phthalo pigment, but I don’t like its texture or hue as much.