Christian, it is a matter of the way TMX renders reds, they come out too light, nothing like Tri X where they are dark and rich. It renders blue darker than Tri X, I believe it was designed this way to render skies better than traditional films. If you look at the picture I posted in the critique gallery, you will see the sky is very dark, this picture was taken without any filters, it is the normal response of 400 Tmx to skies, specially those that are deep blue.

Personally I dont like the way it renders reds, so when ever I can I use a green filter, with some lenses, I dont have the correct size filters so I use them without any filters, like it was the case with the picture I told you, this was taken with an angulon 165, it is so small that I dont have any filters for them.