Please someone correct my explanation to Sylvia. Example: If you use a Kodak TMax 3200 ASA, you may choose to select your camera exposure index, as 800 ASA, and it will work fine. But it will accept if you select as if it has 1000 ASA, and the prints will be just fine too. And so on. But when you want to take pictures in very, very dark places you may select the stops (+ 1, +2 ), as if the film is much more sensitive to light (+1 means that you want that your 3200 ASA film act like a 6400 ASA; +2 like a 12800 ASA). In this case you must overdevelop the film, following Kodak's instruction tables.(posted 8592 days ago)I use the term latitude of a film as the capacity of a film for accept different light condictions, without loosing important information in dark or in bright areas of the picture. Of course that is not as simple as this, but I tryed. Does someone is interested in help me with this "amateur explanation for an amateur"?