I, too, use a Thomas Duplex. It is very bright and can fog paper if the filters are old. You need to perform a proper safelight test like the one Kodak outlines. I have the standard filters in the base and the color filters in the vanes. I can use the vanes halfway open for black-and-white, and fully closed for color. The problem I have with the Duplex is: it's been discontinued. That means that filters are in short supply. Once they are out of stock in stores, I can't replace them when they get old and crack. I cannot get in touch with the company to find out what gels may be used as replacements since they are just gels sandwiched with tissue paper between glass.