Recalibrating film/developers when moving to 5x7?

[Jonathan Lee]

On a whim, I became a 5x7 owner (Ansco) two days ago. I generally use 4x5 TMAX 100/D76 or Tri-X/Rodinal processed in Expert drums on a CPA2 and have densitometrically calibrated these film/developer combinations for my own use. Do I need to redo the testing for 5x7?

Thanks

[Scott Walton]

My answer is yes. I do a test even when a new shipment of film comes in for work. This will also help you see how differently you need to agitate ect to get nice processes. You might need to slow your rotation down or speed it up due to the larger surface of film. A little anal, yes I am but testing has never let me down when I need to know what a particular film/developer is capable of.