A union card refers to the IATSE (International Alliance of Theatrical Stage Employees) union. There are different locals for regions. For example Los Angeles's local is 706. (local706.org) A union card is obtained after an experienced makeup artist has successfully worked a certain amount of days on non-union film productions. Check out the site for what is required, after you have completed the required days of work, you pay your union dues and can begin working union jobs. It can be very complicated when getting into requirements, but if you want to work in the film/tv industry it's a part of it. It's not like a discount card or anything, but a lot of cosmetic companies will except a union card as proof for being a pro makeup artist and then give you discounts.
