As a chemist I tell people to avoid pyrogallol due to its toxicity. This is a dangerous chemical and urge people to read the MSDS for it. The LDlo (lowest lethal dose) is only 28 mg per kilo of body weight which is much lower than other developing agents. it is rapidly absorbed through the skin and so protection like nitrile gloves are a must. In addition it is expensive and oxidizes rapidly in solution.