When I was using the Philips tanning lamp (which of course had 'white' tubes) I was only using the Centennial POP. They took about 35-40minutes IIRC. It was then that I decided to make my own printer in the belief that I could reduce printing times. By the time I had finished the box, POP was no more so I looked for something else and started making Argyroypes with Fotospeed's solution BUT with d***l negs. They took only 7 minutes. I have some solution left and will use it with FP4+ which I am using now. It will be a useful experiment. I am wondering if the film base is not as suitable for tubes as Pictorico.