The Schneider RHOdium Full Spectrum Neutral Density (FSND) filters are a high-end ND filter line made specifically for the critical color standards of 4K, 6K, and 8K resolution cameras. Major advancements in 4K, 6K and 8K digital sensors have resulted in fewer issues with IR leakage compared to digital cameras of the past. However, these imaging sensors can still be subject to IR leakage within the far-red component of the visible spectrum, as well as the near IR. Therefore, IR absorption continues to be a requirement, particularly at optical densities of 1.2 and higher. Schneiders RHOdium FSND filters answers the cinematographers call for a truly neutral ND that controls the IR within the full visible spectrum and into the near infra-red. RHOdium FSND filters are manufactured to finer flatness/parallelism specifications than ever before. These new filters help resolve even the finest detail. Schneider has engineered an extremely thin neutral density interlayer sandwiched between two sheets of crystal-clear Schott water-white glass. The thin interlayer results in excellent transmitted wavefront flatness/parallelism. Additionally the coating is kept safe from abrasions by being encapsulated between the glass, rather than on the surface, thereby withstanding the rigors of the rental market. RHOdiums are the first filters to undergo a lab-tested tristimulus scan, a more critical color measurement than methods previously used to measure filter quality