used to dilute or substitute more expensive safflower dyestuff in the production of . Friedrich Ratzel reported in The History of Mankind during 1896, that in Micronesia, turmeric powder was applied for embellishment of body, clothing, utensils, and ceremonial uses. Native Hawaiians who introduced it to Hawaii () make a bright yellow dye out of it. Indicator Turmeric paper, also called curcuma paper or in German literature, Curcumapapier, is paper steeped in a tincture of turmeric and allowed to dry. It is used in chemical analysis as an indicator for acidity and alkalinity. The paper is yellow in acidic and neutral solutions and turns brown to reddish-brown in alkaline solutions, with transition between pH of 7.4 and 9.2. Adulteration As turmeric and other spices are commonly sold by weight, the potential exists for powders of toxic, cheaper agents with a similar color to be added, such as lead(II,IV) oxide ("red lead"). These additives give turmeric an orange-red color instead of its native gold-yellow, and such conditions led the US Food and Drug Administration (FDA) to issue import alerts from 2013 to 2019 on turmeric originating in India and Bangladesh. Imported into the United States in 2014 were approximately of turmeric, some of which was used for food coloring, traditional medicine, or dietary supplement. Lead detection in turmeric products led to recalls across the United States, Canada, Japan, Korea, and the United Kingdom through 2016. Lead chromate, a bright yellow chemical compound, was found as an adulterant of turmeric in Bangladesh, where turmeric is used commonly in foods and the contamination levels were up to 500 times higher than the national limit. Researchers identified a chain of sources adulterating the turmeric with lead chromate: from farmers to merchants selling low-grade turmeric roots to "polishers" who added lead chromate for yellow color enhancement, to wholesalers for market distribution, all unaware of the potential consequences of lead toxicity. Another common adulterant in turmeric, metanil yellow (also known as acid yellow 36), is considered by the British Food Standards Agency as an illegal dye for use in foods. Medical research Turmeric and curcumin have been studied in numerous clinical trials for various human diseases and conditions, with no high-quality evidence of any anti-disease effect or health benefit. There is no scientific evidence that curcumin reduces inflammation, . There is weak evidence that turmeric extracts may be beneficial for relieving symptoms of knee osteoarthritis, as