Thanks Dave & Bob. I've already got the filter settings from Ilford and they have two settings, one for just the Yellow filter and the other for Yellow and Magenta. Is there a noticeable difference between the two and which is preferable? I'm certainly noticing the difference between the condensor and the dichroic head. It looks as though I may need to go a grade harder than I used to. Is this normal due to the diffusion? A lot of my old negs were developed as per manufacturers spec. If I understand correctly I need to increase development/contrast for a diffusion type head. Can some this be achieved in film rating and exposure (e.g. I normally expose HP5+ at 320) and then using normal dev times or is it purely down to development?