Rollei ATO 2.1 seems clear enough. But when you read about Rollei Ortho 25, the literature says it is panchromatic sensitized. Is it ortho or not? And while we're at it, do you have to use a red safelight with a film like ATO 2.1 or other ortho films, or can you use a regular OC filter. I'd like to avoid buying a red filter if possible, but not sure if OC will be safe. I guess it depends on the spectral sensitivity of the specific film, but information on this stuff is scarce. I want to use ATO 2.1 for masking.