title: Tiff versus BigTiff
body: <p>Please let me know if there is another Stack Exchange community this question would be better suited for.</p>
  
  <p>I am trying to understand the basic differences between Tiff and BigTiff. I have looked on various sites and the only difference that is mentioned is that BigTiff uses 64-bit offsets while Tiff uses 32-bit offsets. That being said, you would need to know which of the two types you are reading. How is this done? According to <a href="https://www.leadtools.com/help/leadtools/v19/main/api/tifffmt.html" rel="nofollow noreferrer">https://www.leadtools.com/help/leadtools/v19/main/api/tifffmt.html</a>, this is done by reading a file flag. However, the flag they are referring to appears to be unique to their own reader as I cannot find a corresponding data field in the specifications as shown by <a href="http://www.fileformat.info/format/tiff/egff.htm" rel="nofollow noreferrer">http://www.fileformat.info/format/tiff/egff.htm</a>. What am I missing? Does BigTiff use a different file header than Tiff?</p>