Robert, it depends on whether you want to go through the entire film development process in total darkness, or merely load your film in the dark and then proceed with the lights on. Avoid developing tanks for 4X5 film. Tank development works fine with 35mm and medium format film, but it is extremely difficult to get even development in a sheet film tank. Jobo processors are the exception, but they are expensive. If you are planning on doing high output developing, look for a good buy in a used Jobo outfit. Personally, I've learned to develope sheet film in trays, in total darkness, and I am comfortable doing 6, or 8 films at a time. It's relatively simple to do, but takes practice. Quite a lot of detailed planning is necessary in order to create a totaly light- tight darkroom and still maintain fresh air circulation. I use 8X10 trays for 4X5 sheet film. Two 8X10 trays fit into a 16X20 tray that is used as a water temp. control bath. I usually need to chill the chemicals down to 68 degrees F by using plastic zip-loc bags filled with ice in the temp. control bath. Now here's an easier way to go: buy a Polaroid 545 film holder and use Type 55 film. It will give you a proof print and a negative, and you will never need to worry about the development process.