The first type of dispute that comes to mind when reading these facts is whether there is copyright infringement by the tattoo shop displaying your work. Based exclusively on the facts provided, you appear to be in the right, because, under the current Copyright Act, a work is “made for hire” (and owned by the employer) only if (1) you are an “employee” when creating the work or (2) you expressly agree that the work is “made for hire.” Thus, when you are an independent contractor and there is no agreement as to who owns the work, the presumption, under the Copyright Act, is that YOU own the work and can enforce those provisions of the Copyright Act regarding publication, copying, and display.
But it is important to note a few things. To call yourself an “independent contractor” (even if both you and your employer called you that, and even if there was a written contract and you were treated for tax purposes as an independent contractor) may not be conclusive proof that you were, in fact, an independent contractor. According to the U.S. Supreme Court (Community for Creative Non-Violence v. Reid, 1989), to determine whether you are an “employee” under the Copyright Act, you look to the law of agent-principal relationships. Factors relevant to this inquiry include, among other things: (1) the employer’s right to control the manner and means by which you created your work; (2) the skill required; (3) the owner/source of the instruments and tools used; (4) location of the work; (5) duration of the relationship; and (6) payment arrangements. Notably, if you were required to be in the shop for set hours to handle whatever potential clients walked into the shop, you may have an uphill battle trying to prove that you were not an “employee” for purposes of the Copyright Act.
The “independent contractor” v. “employee” debate is a case-by-case struggle, and it is one for which an attorney would be helpful, particularly if this issue advances to a lawsuit.
Most would start with a well-crafted cease-and-desist letter.
The information provided in this and other answers on Avvo are general in nature and limited to the facts as stated. The information provided in this and other answers on Avvo should not be construed as legal advice on which the reader relies without further consultation with an attorney. No attorney-client relationship is created on Avvo question & answer forums. This attorney is licensed and admitted to practice law in the State of Florida only.
You will likely need a local FL lawyer to send a CDL [cease & desist letter] as a shot across the bow to this ink shop. However, first take any paperwork between you and the shop and a log of financial transactions between the you and the shop to that lawyer to be sure you are, in fact, an indie.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.