one shot was with xray film the other shot with delta 100

[ImSoNegative]

i did two shots today one with green senstive xray film, the other with ilford delta 100, both were exposed at 1/15 sec 14in. brass petzval, both at iso 100, the reason i was doing this was because is there really that much of a difference to justify me paying 90 dollars for 25 sheets compared to 35.00 for 100 sheets, tell me which was done with xray and which was done with regular film and why you think so. excuse all the damn dust.