Cadmium was discovered as an element the early 19th century in contaminated zinc oxide samples. The discovery is widely attributed to German chemist Friedrich Stromeyer, although others were involved in its discovery. Cadmium pigments range in color from yellow-green, yellow, orange and red. Many historical red pigments were problematic due being fugitive, that is, fade under light Cadmium pigments revolutionized art by being much more lightfast and having a much higher tinting strength and opacity than existing pigments such as mercury sulfide (vermilion). However, they are sensitive to air exposure and their application in murals and frecos is more limited. Some watercolor artists also do not like cadmiums due to their opacity.
Despite it being ubiquitous in artist paints in the 19th and 20th centuries, cadmium is toxic and exposure is thought to increase the risk for cancer, kidney and liver problems. The U.S. Environmental Protection Agency considers cadmium as a probable human carcinogen. Inhalation can also cause respiratory problems. However, the major risks are associated with working with large quantities of cadmium in industrial settings (used in coatings, plating, plastics manufacturing, battery manufacturing and recycling, etc.) and artists paints with cadmium are generally not considered dangerous (also see here). However, the precautionary principle should always apply and artists are encouraged to use common sense and protect themselves from ingestion and inhalation. Cadmium alternatives have also been developed. Liquitex for example has developed cadmium-free acrylic paints that imitate the original cadmium pigments in terms of lightfastness, opacity and tinting strength and to me they are indistinguishable to the originals. Their development was spurred by a proposed ban on cadmium pigments by the European Chemical Agency (ECHA) in 2014 over concerns about its presence in the food chain as a result of sewage sludge applications over farmlands and potential adverse effects on bone health and cancer. In other words, it was suggested that artists washing contaminated materials down the drain contributed to this problem. After opposition from artists and arguments that nickel-cadmium batteries were the main cause of the problem, the ECHA abandoned the proposed ban. However, cadmiums were banned in jewelry and plastics.
Over time, the cadmium pigments have been replaced by azo pigments, but some of these can be less lightfast than the cadmiums. In addition, synthetic pigments such as the quinacridone pigments are intense and lightfast alternatives which were developed for use in the automotive industry and industrial coatings, but are now used by many fine art paint manufacturers. It is good to be an artist in the 21st century with so many safer, lightfast and potent alternatives available. Although I confess it can get overwhelming and paralyzing to take the time to do the research and choose the best (and safest) pigment alternatives out there. I am not here to limit or police how artists conduct their art, just to motivate artists to take some necessary precautions to protect their health and that of the environment, which eventually comes to affect us all.
According to the U.S. EPA, most of the cadmium used in the U.S. today is a byproduct of smelting of zinc and copper ores. Cadmium can become airborne when fossil fuels and municipal wastes are burned. Mining can have devastating impacts beyond the most evident scarred landscapes. It can affect local biodiversity, soil, air, water and food quality, and even human rights. Although artists demand for cadmium pigments is relatively minimal compared to other uses, we have a responsibility when it comes to its fate and transport in the environment. Here are some things that artists can do to minimize the potential adverse health and environmental impacts from use of cadmiums and other toxic pigments:
Do not wash your paintbrushes, rags and contaminated water down the drain. Try to get as much pigment off your brushes by cleaning them on a rag first, then clean them in a big bucket of water, let the solids settle for a few days. Then you can carefully throw the cleaner water at the top of the bucket down the drain or even better, use a coffee filter to minimize the smaller particles going down the drain. You can then let any remaining water evaporate from the bucket and after a few days remove the solids and take them to your local landfill for proper disposal.
Do not put brushes near your mouth when painting.
Use alternatives to cadmium pigments such as quinacridones, azos, etc.
Use extra protective equipment such as gloves and respirators when dealing with toxic materials.
Please leave any other tips below and thank you for reading!