Hi, I am heading to this forum again for a wonder about ilfochrmome filtering. I use a color head enlarger (Meopta 6a) which is toped at 200 in C, Y and Magenta and the ilfochrome filters are toped at 50. A simple rule tells me that: 5 in ilfochrome is equal to 20 on my enlarger. 10 in ilfochrome is equal to 40 on my enlarger. And so on... Here is my wonder: Filtering with the head seems denser that it is with Ilfochrome Filters. For filters I do it bellow the lens. Might it be the reason?