In general, red is 'safer' than amber (OC), but there are different reds. There is light red (#1A), red (#1) and dark red (#2). Dark red is 'safe' enough to work even with orthomatically sensitized emulsions (some Foma papers), but it isn't very bright. I have tested them to be 'safe' up to 16 minutes. Light red should be safer than amber from a wavelength point of view, but it is very bright, and I haven't found them to be 'safe' beyond 2 minutes. Red (#1) and amber (OC) are both good for regular emulsions, with red being safer than OC if you can stand the red light in the darkroom. To be sure, you should test with your paper, and if in doubt or more time is required, add some paper (from the outside!) as a neutral density filter.