The Ilford Multigrade filter set is used for the targeted contrast control of variable-contrast papers. The contrast control takes place during exposure. The RC film filters are numbered from 0 to 5 in half grade steps. A twelfth filter numbered 00 completes the set. This allows you to enlarge even extremely hard negatives. The Ilford Multigrade filters can also be used under and above a magnifying lens. However, the filters work best when placed in a filter drawer above the negative. The polyester backing allows you to tailor the filter to the size of the filter drawer. Unlike some other filter systems, the Ilford Multigrade filter set is very easy to use. They are density-balanced which means no complicated calculations are needed when changing from one filter to another. Filters 00 to 3 ½ require the same exposure; filters 4 to 5 require twice as much exposure. The complete filter set is available in the formats 8.9 x 8.9 cm or 15.2 x 15.2 cm.