I recently bought a used zone VI cold light for my Omega D-2. It is an older li ght (aluminum finish) and when I put it in the enlarger, I can clearly see the p attern of the light tube projected onto the easel. The light has a diffuser att ached but maybe it needs another? Any ideas? I'm sure that if I tried to print with it the pattern of the light tube would be discernible in the print. Has a nyone experienced similar problems and developed a solution?

Thanks in advance, Mark