My experience with 6x7 t-max 100 would indicate that Ilford 100 might not fill the bill for 20x24's from a 6x4.5 negative. With full frame 6x7 t-max 100, grain just starts to become visible in the mid tones (sky)at 16x20 sizes. A 16 x20 from a 6x7 negative is about a 7.2X blowup. A 20x24 print from a 6x4.5 negative is about a 10.9X blowup. This size enlargement will have a lot of visible grain.(posted 9102 days ago)If you want clean enlargements of 10x or larger, Tech Pan is the film to use. I use Tech Pan both 35mm and 120 and can assure you that a 10X enlargement will be grain free.