In light of yesterday’s blog concerning toxins found in Cadmium Yellow, I stumbled across an interesting article by Nicole Tonkham for Keetan’s Office and Art Supply. Tonkham takes on the challenge of understanding the chemical makeup of yellows in her 2016 article “16 Shades of Yellow: Understanding Pigments.”
The article can be found at: https://keetonsonline.wordpress.com/2016/02/04/16-shades-of-yellow-understanding-pigments/
Tonkham writes: “Cadmium yellow, Hansa yellow, Naples yellow… all yellow, all completely different colors. How can this be? Yellow is yellow, right? In the world of art, describing a color as “yellow” just won’t cut it. There are warm yellows, dull yellows, muted yellows, intense yellows, rich yellows, opaque yellows, and the list goes on. Is your head spinning yet? With so many options, you may be wondering how to determine the best yellow paint for your next project. To do that, you must understand PIGMENTS. Here’s the pigment low down so you know exactly what you need.”
She goes on to explain the differences between the various yellows pigments, dividing them into three main categories: Earth, Mineral, and Organic.
Earth Pigments: Pigments found in the earth that tend to be opaque when modified with a modern process. Their intensity lessens when mixed with other colors. These are often muted colors (such as ochres and siennas) that have been used since artwork emerged on cave walls.
Mineral Pigments: These pigments are found from metals, most being created during the Industrial Age began. Cadmium Yellow is a great example of this where the mineral pigment cadmium sulfide was used to create it. They tend to be opaque; low in tinting strength and high in chroma (purity/intensity).
Organic Pigments: These are derived from pigments containing carbon, such as Hansa Yellow’s arylide. They are normally transparent and high in tinting strength and chroma (purity/intensity). These pigments will yield the most intense yellows.
Tonkham’s Cheat Sheet:
Nickel Titanate Yellow- Mineral
Cadmium Chartreuse- Mineral
Cadmium Lemon- Mineral
Cadmium Yellow Light- Mineral
Cadmium Yellow Medium- Mineral
Cadmium Yellow Deep- Mineral
Radiant Yellow- Mineral
Radiant Lemon- Mineral
Hansa Yellow Light- Organic
Hansa Yellow Medium- Organic
Hansa Yellow Deep- Organic
Indian Yellow- Earth
Naples Yellow Hue- Earth
Yellow Ochre- Earth
Gold Ochre- Earth
Transparent Earth Yellow- Earth
As painters and those in charge of purchasing paint products, we often forget to really look at the supplemental information that is included in Material Safety Data Sheets. There is often a hidden layer of ingredients that goes beyond the binder and filler outlined in the MSDS. We need to remember where the pigments originate from and the basic toxins present within every hue.
My main message is that all artists need to educate themselves about every product they handle…and don’t stop there! Educate your students, staff, co-workers, and superiors. Think about what you are creating and the safest products to use before purchasing paint supplies.
On a similar note, Environmental Health News posted an article titled, “Yellow Pigments in clothing, paper contained long banned PCB (Polychlorinated biphenyls).” PCB-11 was banned in the United States 35 years ago, but was recently detected in nearly all samples of paper products sold in 26 countries and clothing sold in the United States. Because it is an unintentional byproduct of manufacturing, the PCB-11 found in consumer products is exempt from U.S. laws regulating the compound. This really is a must read:
http://www.environmentalhealthnews.org/ehs/news/2014/feb/pcb-pigments
