I have used the 8x10 arista and it seems to be the same as the 4x5 FP4+ that I had used previously. I have gone through four boxes so far and have been very pleased with the results. No problems or defects except for the ones that I produce. I don't know for sure which emulsion it is but unless freestyle bought a few big rolls of film before FP4+ went into production it is most likely FP4+