The investigators hypothesis is that chlorhexidine based skin preparation solutions erase site marking in comparison to iodine based skin preparation solutions. The investigators intend to prospectively study twenty patients undergoing total hip arthroplasty. Patients will be randomized to either a chlorhexidine based or an iodine based skin preparation solution. These solutions are both the current gold standard of clinical care. No differences have been shown in infection rates for total hip arthroplasty between these solutions. The site marking will be performed by the same surgeon in a standardized manner. The site marking will include the surgeon's three initials as per usual routine. Underneath the initials three random initials will be placed with a horizontal line drawn underneath. The preparation of the skin will be performed according to the manufacturer's specifications. Digital photographs will be taken of the skin marking after skin preparation. Photographs of the three random initials will be de-identified and placed in a "Powerpoint" presentation form. Ten orthopaedic surgeons will then read the site markings to identify the random initials and to tell whether the mark looks appropriate to perform a surgical timeout. The horizontal line will be digitally analyzed using Adobe Photoshop to quantitatively measure blackness of the mark.