This article explains a repeatable way to measure watercolor granulation. We analyze the L* (lightness) variation inside a representative 1-inch tile of the wash, remove the paper’s own texture, and scale by mean lightness to get a Granulation Index (GI). The GI is then labeled None, Slight, Moderate, Strong, Very Strong, or Extreme so you can compare colors and papers with confidence.
Watercolor artists often describe paints as staining or non-staining—but what does that really mean? In this in-depth guide, Natural Pigments explains how watercolor staining is measured scientifically using a repeatable method based on the Residual-Color Index. Learn how to prepare filter-paper swatches, test lifting behavior, and understand what the labels “Non-staining,” “Low,” “Medium,” and “High” actually tell you about pigment behavior.
Objective, tint-first hue labels for watercolors—based on CIE Lab* data. Clear warm/cool rules and a reliable way to classify tricky browns and blacks so your mixes behave on paper.
The founders of Natural Pigments recently met James Gurney and his wife, Jeanette, at the Plein Air Convention in Monterey, California. James is the author and illustrator of the book series Dinotopia. This highly imaginative book series details the world of dinosaurs in a utopian setting, hence the name.
The Reeves brothers are credited with the invention of watercolor cakes. Since the introduction of watercolor cakes over 200 years ago, manufactured watercolor paint has changed how artists work. Artists no longer must laboriously grind pigment in gum water to make paint and tirelessly rub hard cakes to get color.
Did watercolorists of the 18th and 19th centuries use mediums to brush and manipulate their watercolors? The evidence shows that they handled their colors differently from contemporary artists today. Here are some historical references on the use of watercolor mediums by British watercolorists of the 18th and 19th centuries.
Rublev Colours Artists' Oils let you experience what the old masters well understood—the unique characteristics of pigments. The pigments used by old masters in their paintings were ground from natural minerals and earths, fermented in dyer vats, and concocted in alchemist laboratories. Rublev Colours Artists' Oils give you the same pigments used by the old masters prepared with linseed oil as ready-made paints.
Rublev Colours* artists' paints are made in the United States by Natural Pigments that include Artists' Oils, Watercolors, and painting mediums for use by professional fine artists. Rublev Colours are different from other commercial artists' colors. One reason is we use natural and historical pigments like those used by the old masters. Another is we make them as they did before modern artists' paint manufacturing—without synthetic, modern additives.
Ackermann’s Superfine Water Colours were prepared and sold at Rudolph Ackermann’s shop, The Repository of Arts at 101 Strand in London, and also sold through print and booksellers in Great Britain. He published a list of watercolor cakes that appeared in 1801 and was appended to A Treatise on Ackermann’s Superfine Water Colours.
Glycerin (also spelled glycerine and also called glycerol) is a humectant and plasticizer ingredient in commercial watercolors today, but it is not always an ingredient in commercial watercolors. An examination of watercolor paints from the late 18th and early 19th century reveals that glycerin was not a plasticizer and humectant in pan watercolors (called 'cake' colors in that period). For example, Rudolph Ackermann used crystal sugar melted in water as the plasticizer and humectant for many colors. In some cases, the recipes called for vinegar!
