http://www.amazon.com/ILFORD-Filters-3-5-Inches-1762628/dp/B00009USUJ/ref=wl_it_dp_o_npd?ie=UTF8&coliid=I29YFP919IF0KN&colid=EI7HQJ6EOGHS
They're filters, they either decrease or increase the contrast of photographs. I love photography a lot and really want them, but I can't afford to buy filters with the cost of darkroom chemicals and paper thrown in on top of that.