I recently added an Aristo 1212 cold light to my 8X10 enlarger. I am unable to get much contrast out of Agfa and Forte VC papers. When I add a number 4 printing filter, the exposure becomes very long with very little additional contrast. I bought the light used. The lamp emits a rather green light. The folks at Aristo said that the V54 tube should look "agean green". It does. So whats up with the contrast? A print on Seagull G grade 3 looked fine but required a long exposure. I am willing to buy a new V54 tube from Aristo but I need to be sure I don't already have one. Please advise.