Romero explains that research has become the most important and difficult part of his work in recent years. Romero spends much of his time studying the ideas that will nurture his paintings. For the Corpus Christi series, Romero explored the search for god as a whole theme that englobes different subtopics i.e. idolatry, belief, rituals, salvation, etc. For Teeth and Everything that Mattered, Romero looked into the concept of mortality and the facts and fictions we have built around it. 

Romero’s process is based upon a thorough and in-depth analysis of imagery. To make work, Romero scrutinise images that he collects or take photos himself. Once Romero finds an image that he feels himself drawn to, he will paint it over and over again in an attempt to reveal its essential, mystical form. Through painting and repainting, each incarnation of the work pulls out ideas around power, authority and interpersonal relationships.