Film speed is found from a plot of optical density vs. log of exposure for the film, known as the Dlog H curve or HurterDriffield curve. There typically are five regions in the curve: the base + fog, the toe, the linear region, the shoulder, and the overexposed region. For black-and-white negative film, the "speed point" m is the point on the curve where density exceeds the base + fog density by 0.1 when the negative is developed so that a point n where the log of exposure is 1.3 units greater than the exposure at point m has a density 0.8 greater than the density at point m. The exposure Hm, in lux-s, is that for point m when the specified contrast condition is satisfied. The ISO arithmetic speed is determined from:
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the ISO arithmetic speed?
Ah, so.. unanswerable

There are many names for God, and different names are attached to different cultural ideas about God's identity and attributes. In the ancient Egyptian era of Atenism, possibly the earliest recorded monotheistic religion, this deity was called Aten, premised on being the one "true" Supreme Being and Creator of the Universe. In the Hebrew Bible and Judaism, "He Who Is", "I Am that I Am", and the tetragrammaton YHWH are used as names of God, while Yahweh and Jehovah are sometimes used in Christianity as vocalizations of YHWH. In the Christian doctrine of the Trinity, God, consubstantial in three persons, is called the Father, the Son, and the Holy Spirit. In Judaism, it is common to refer to God by the titular names Elohim or Adonai, the latter of which is believed by some scholars to descend from the Egyptian Aten. In Islam, the name Allah, "Al-El", or "Al-Elah" ("the God") is used, while Muslims also have a multitude of titular names for God. In Hinduism, Brahman is often considered a monistic deity. Other religions have names for God, for instance, Baha in the Baha'i Faith, Waheguru in Sikhism, and Ahura Mazda in Zoroastrianism.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the Christian God called?
Ah, so.. Yahweh and Jehovah

Stephen Hawking and co-author Leonard Mlodinow state in their book, The Grand Design, that it is reasonable to ask who or what created the universe, but if the answer is God, then the question has merely been deflected to that of who created God. Both authors claim however, that it is possible to answer these questions purely within the realm of science, and without invoking any divine beings. Neuroscientist Michael Nikoletseas has proposed that questions of the existence of God are no different from questions of natural sciences. Following a biological comparative approach, he concludes that it is highly probable that God exists, and, although not visible, it is possible that we know some of his attributes.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the name of the book by Michael Nikoletseas?
Ah, so..
unanswerable