I want to know the answer to the following question:
What consists of 25 pigmented squares touching a plate below a phosphorescent tablet under the light of a burning Magnesium ribbon?
All the background I'm provided with is that "The speed of the emulsion was then expressed in 'degrees' Warnerke (sometimes seen as Warn. or °W.) corresponding with the last number visible on the exposed plate after development and fixation.". Is that enough to answer the question?
Answer: no