Your skin has cells called Melanocytes, which uses the amino acid tyrosine (also an added ingredient in indoor tanning lotions) to produce melanin which is the protein that turns brown and gives your skin a tan color. Everybody has about the same amount of melanocytes but the amount of melanin they produce varies and that’s why people have different skin colors.
The Fitzpatrick Skin Type System was developed by Harvard University Dermatologist Dr. Thomas Fitzpatrick to determine how sensitive to sunburn any tanner is based on hereditary characteristics like eye and hair color as well as their response to UV exposure. The scale has 6 categories for skin types: the darker the skin (or more pigment naturally) the less likely they are to burn, however people with more melanin and darker skin also require more UVB exposure to produce Vitamin D.
This skin type tool is used by all reputable tanning facilities to determine exposure time in the tanning bed to minimize the risk of sunburn. Sunburn should be avoided at all costs. The belief from the 80’s that you had to burn first before skin would tan is absolutely false and cause far more damage on a cellular level and increase the risk associated with sun exposure.