I'm looking for some 5" X 5" or around that size contrast filters for a Bessler enlarger MCRX 4x5 B&W. There is a drawer above the condenser and I would like to put them above the negative. Can anybody recommend where I might find something or are they still available? I'm using Ilford Multigrade paper. Not sure if that will make a differance. I believe I read that Kodak makes that type of filter. I'm just new to LF.