The viewing filter shortage! I am hoarding my 2 sets. I always used them and my eyes instead of an analyzer. I have several analyzers, but I’ve never used them because you have to make the “perfect print” first. After I make the perfect print I just keep on printing! Small adjustments I find are easy to determine with the viewing filters after that. One of these days I’ll get around to making a ring-around.
A lot of people do tray printing at room temperature, but I don’t like standing in the dark much and I find the developer smell to be intolerable- but I know many are not as sensitive. I liked using drums before I got a roller transport machine.