Occasionally, I have found myself wanting to test the tinting power of certain paints in my drawer. This usually happens after I purchase the less expensive brand of a color I have wanted, and find the need to kick myself for not spending the extra money upfront for the higher quality paint. Watching a color disappear when added to a pile of white is extremely frustrating - to the wallet as well as the mind.
As Frederic Taubes stated in his 1943 book, Studio Secrets, "Generally, the best colors have the greatest tinting strength, whereas cheap colors are deficient in this respect."¹ His suggestion for evaluating the power of paints is to employ a simple tool to mix equal quantities of different brands of a single color, with equal quantities of white, and then compare the results. The instrument, as pictured below, is just a small metal plate or wooden board, ⅛ to ¼ inch thick, with two small openings, about the size of penny, cut through the panel. Using this tool, equal volumes of white and the color to be tested can be made. Just fill each side with paint, level it with a palette knife, then lift the panel and mix the two discs together. Do this again for each brand, and hopefully, the results will clearly show which paint is the best (i.e. has the greatest pigment strength).
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| Frederic Taubes' drawing of his paint measuring device |
When I considered testing the power of paints in my possession, I decided to start with Prussian Blue, an ancient and highly staining color which is a regular part of my palette. Normally I use a Prussian Blue made by Winsor & Newton, but when I got my hands on Rublev Prussian Blue from Natural Pigments, a company which eschews fillers and stabilizers in its paints, I was curious to see how the two compared.
Originally, I made a tool like that suggested by Taubes out of a piece of ⅛ thick hardboard, but later decided to modify the design to suit the pigment Prussian Blue, which at equal volume might be expected to quite overpower the white. Instead of two equal-sized openings, I made an instrument with two holes of vastly different sizes (the ratio of the sizes is not pertinent, as long as the same tool is used for each brand of paint).
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| Taubes' tool worked pretty well, though the Rublev paint did not drop through the opening as well as the Winsor & Newton paint had done (I had to scrape the Rublev paint from the hole with my palette knife). I chose to use Titanium white because of its opacity (and because it is much cheaper than my lead white). |
I placed the tool flat on my palette and filled the smaller hole with Winsor & Newton's Prussian Blue, and the larger with Titanium White. I then cleaned the plate, and repeated the process with the Rublev Prussian Blue. Afterward, I mixed the two pairs of piles together, and then compared the outcomes.
Knowing which paint has the greater tinting strength is important to me because it affects my future purchases: a more highly concentrated pigment is of greater value, and will go further in mixtures on my palette.
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| Here are the two mixtures in comparison to an Xrite ColorChecker. Winsor & Newton is on top; Rublev on the bottom. |
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| Rublev is darker in value because of its higher pigment concentration. |
Winsor & Newton Prussian Blue lists for $11.99 for a 37 ml tube ($.32 per ml).
Natural Pigments' Rublev Prussian Blue lists for $14.95 for a 50 ml tube ($.30 per ml).
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| I converted my picture to black and white and compared the results to the Munsell Scale from The Classical Lab app "Grayscale Converter." The Winsor & Newton Prussian Blue tint was approximately a 7 on the scale, while the Rublev was a full step darker. |
¹ Taubes, Frederic, Studio Secrets, (Watson-Guptill Publications, Inc., New York, 1943), p. 79.
Studio Secrets on Amazon.com.
Prussian Blue at Natural Pigments.
Grayscale Converter at The Classical Lab.