A month ago, we moved from the Carolina coast to the Appalachian mountains, and I immediately discovered that my carefully chosen watercolor palette that worked so well at the coast was all wrong for these high country hills.
You can see most of my current palette colors here, and though I still love, love, love this assortment and it works great for (most) travel, I need to make some changes to reflect the everyday scenery around me.
This mountain range is known as the "Blue Ridge" for a reason, so I'm beginning my palette revamp with the blues. I have always used Ultramarine as my go-to blue, but I recognized my first week here that ultra wasn't working in these mountains. Ultra's purplish warm hues may perform better here this summer, but right now, I need something a little different for these snowy hills and dales.
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Comparing Ultramarine Watercolors
My first "real" watercolor set was a Sennelier travel set. Sennelier's cobalt looked almost exactly like its ultramarine— just check out the photo below. (Click on any of the images to enlarge.) Since I really couldn't tell a difference when painting but I preferred the strength of ultramarine, that's the color I stuck with.
At the time, I didn't realize that different brands and names of watercolors varied widely. Or that there was such a thing as granulating, transparent, or staining pigments. Or how to read a watercolor label. Or that ultramarine was a completely different pigment (PB29) than cobalt (PB28). If you are interested, you can learn more about watercolors and how to read labels here.
I won't try to reinvent the wheel because other artists have profiled watercolor pigments much better than I ever could. (I especially love Jane Blundell's website and blog for exploring the various watercolor brands, pigments, and mixes.) But I do want to show you what I mean when I say that colors vary widely. Below are several ultramarine watercolor swatches, and all are exactly the same pigment, PB29, which stands for Pigment Blue #29.
Comparing Cobalt Watercolors
When I recognized that ultramarine wasn't working for me here, I immediately sought out cobalt. I wanted to try cobalt because so many artists compare it to my beloved ultramarine... sort of. There are clear differences. (And I'll get to those below in Cobalt vs Ultramarine: What's the Difference?) Being familiar with some of these characteristics, I thought that cool cobalt might work better as a go-to mountain blue.
I trekked down to the art store and grabbed the smallest tube of artist-grade cobalt I could find (oh when will you paint manufacturers sell over-the-counter testers?!?!), Winsor & Newton Professional (PB28). This pigment code stands for Pigment Blue #28, which is the standard blue pigment used in cobalt watercolor. Quite pricey, but the best I could do in a pinch.
W&N cobalt turned out to be a lovely, clear, soft shade of blue and has worked much better than ultramarine for capturing these misty mountaintops and snow-dusted hills.
Since then, I've played a bit with various cobalts. All of the cobalts below are PB28 except for Grumbacher Academy's student-grade cobalt hue, which really looks more like an ultramarine. And that's because it is! (I know, tricky. Right?!?)
Many cobalt hues and student-grade "cobalts" use PB29, which is the usual pigment in ultramarine, or even other blue pigments to lower costs. This can be confusing for a beginning watercolor artist and is a perfect example of why it's important to ignore manufacturer names and learn to be a label reader.
Cobalt in Mixes
As much as I enjoyed playing around with Winsor & Newton cobalt, I noticed that it didn't perform well in mixes. It is so delicate that it quickly went washy, even with very little water.
I rarely use any pigment straight out of the tube but prefer to adjust it, or "dirty it up a bit." Because of this, I was hesitant about giving W&N cobalt a permanent place in my palette so I experimented with a few more brands.
So far, my favorite cobalt in mixes has been M. Graham's cobalt. It looks a lot stronger on paper than the W&N (con: not as easy to do smooth glazes and washes) but holds up pretty well in a mix (plus). It's also more affordable than W&N (plus plus).
You can see in the cobalt swatches above that the Daniel Smith sample dot was barely enough to paint a swatch. I'm interested in experimenting more with DS cobalt, though it will have to be at a later date. Another tube of cobalt just isn't in my budget this month.
In the chart below, you can see that M. Graham cobalt it is more vibrant than W&N, especially in the earth tone mixes, but cobalt still can't compare to the excellent mixes that I get with ultramarine.
Cobalt vs Ultramarine: What's the Difference?
I'm not the first to ask this question (for example, see this thread on Wet Canvas) and I'm sure I won't be the last.
When comparing cobalt to ultramarine, there are a few important differences to note.*
- Ultramarine is typically warmer; Cobalt tends to be cooler. Cool colors like to recede in a painting, so cobalt may work better for shadows and in the distance while ultramarine prefers attention.
- Ultramarine is transparent; Cobalt is semi-transparent. If cobalt is mixed with a transparent color, it may separate (see photo.) Some really like this effect; some do not.
- Both are granulating pigments, but cobalt tends to be less so and appears clearer. This makes cobalt the winner in glazing where ultramarine may streak or settle unevenly. But again, cobalt can appear highly granulating when mixed with a transparent pigment. (But again, see photo.)
- Ultramarine tends to be more intense than cobalt, while cobalt is known for being delicate. Because of this, ultramarine may hold its body better in mixes while cobalt may wash out.
*It's also important to note that these similarities and differences vary widely between tubes and brands. And also between the various pigments like cobalt and cobalt blue hue, etc. You may have to try several brands before you find one (or two!) that you love.
Cobalt vs Ultramarine: The Winner?
So which one is for you? Maybe both! Ultramarine and cobalt sit side by side in many an artist palette, and I'm currently keeping both in my studio palette at home. This ups my number of blues to 5 (eek!) so I'm not sure if all these blues will stay, but for now I'm having fun with this plethora of pretty pigments.
As for my limited travel palette... who knows! I just can't get the mixes with cobalt that I can with ultramarine, but I'm open to changes and much more experimentation.
If you are a minimalist at heart and can't stomach the idea of both pigments, paint the exact same landscape twice but use ultramarine for one and cobalt for the other. That may give you an idea of the differences between the two. Regardless of location, some just prefer the cooler touch of cobalt or the radiating warmth of ultramarine.