Film Photography Discussion

Hi,

I have mixed some ECN-2 chemistry according to Kodak's guide. Unfortunately I am having some issues with development.

The pictures at the end of the roll are way less dense than the start and middle. This happened to two distinct rolls in the same tank, and I don't think I just happened to underexpose the last 12 or so images on each.

here is the good part of a roll

Here is the extremely underdeveloped part of the same roll

The weird thing is that the edge markings are developed throughout the whole roll. Any idea why this is happening to me?