Red filters require three stops more exposure, so make sure you are metering properly. The next step is to develop the film for your enlarger, or work with your lab to nail the exposure/development process for your work. If you aren't developing the film yourself, you will need to tailor your exposure to the lab's processing technique. Talk with the person who develops and prints the film.(posted 9710 days ago)If you are deveoping the film yourself, try an extra 30 seconds in the developer to bring out more contrast. We really need more information to give specific tips, because your film developer, enlarger, paper and paper developer will all effect your contrast.