I want to know the answer to the following question:
What does the last exposed number on the plate represent?
All the background I'm provided with is that "The Warnerke Standard Sensitometer consisted of a frame holding an opaque screen with an array of typically 25 numbered, gradually pigmented squares brought into contact with the photographic plate during a timed test exposure under a phosphorescent tablet excited before by the light of a burning Magnesium ribbon.". Is that enough to answer the question?
Answer: no