Leave the colors to the artist. Hamlet suggests not bringing in a fully rendered drawing of the image and colors you want. The more I interview tattoo artists, the more I am coming to understand that getting a tattoo is like commissioning an artist to paint a mural. You do own the building, but you don't hand the artist a photo of another artist's mural and tell them to replicate it for you. Instead, you say your building works for peace and you want a mural that conveys that message and that you especially love lily of the valley flowers and the image of the rising sun. Then you let the artist do what they do: Create some art!
The FDA regularly issues warnings to consumers about avoiding any temporary tattoos labeled as black henna or pre-mixed henna as these may contain potentially harmful ingredients including silver nitrate, carmine, pyrogallol, disperse orange dye and chromium. Black henna gets its color from paraphenylenediamine (PPD), a textile dye approved by the FDA for human use only in hair coloring. In Canada, the use of PPD on the skin, including hair dye, is banned. Research has linked these and other ingredients to a range of health problems including allergic reactions, chronic inflammatory reactions, and late-onset allergic reactions to related clothing and hairdressing dyes. They can cause these reactions long after application. Neither black henna nor pre-mixed henna are approved for cosmetic use by the FDA.
The word tattoo, or tattow in the 18th century, is a loanword from the Samoan word tatau, meaning "to strike". The Oxford English Dictionary gives the etymology of tattoo as "In 18th c. tattaow, tattow. From Polynesian (Samoan, Tahitian, Tongan, etc.) tatau. In Marquesan, tatu." Before the importation of the Polynesian word, the practice of tattooing had been described in the West as painting, scarring or staining.