Terrence Brennan
Member
Is there a source for making long exposure reciprocity calulations for Double-X 5222? Kodak only indicates that the film doesn't require adjustment from 1/10,000 to 1 second.
Ilford has a calculation for their films for making long exposures in which the indicated exposure time is raised to a specified power to get the final exposure time. For example, with HP5 Plus, one takes the indicated time--say 8 seconds--and raises it to the power of 1.31, which gives 15.24 seconds, which rounds up to 16 seconds.
Ilford has a calculation for their films for making long exposures in which the indicated exposure time is raised to a specified power to get the final exposure time. For example, with HP5 Plus, one takes the indicated time--say 8 seconds--and raises it to the power of 1.31, which gives 15.24 seconds, which rounds up to 16 seconds.