Are you saying that the unit has red filters in the base and yellow in the swinging windows? I have a Thomas sitting up in my darkroom but have not used it. I have a separate OC and a Red, ortho safelight I use. With the Thomas I would have to change the filters or are you saying you open the wings for one and close them for the other? The units are heavy, lights expensive, filters expensive, but really bright. I haven't had the courage to put it into use yet. After I bought it I wondered why I did, do I really need it?