It gets dark when im in survivial mode and in my tunnel

[Johne171]

for whatever reason when im in my minning tunnel which is very long i can see all the way to then end of it instead it looks like my tunnel is very dark but when i switch to creative mode i can c all the way to the end of it.

Any idea what going on here

[disconsented]

That is Optifine IIRC

[Viktor_Berg]

That's the depth fog. It gets worse at lower depths, and is disabled in creative. You can also disable it in Optifine (which Technic Pack has) - check in Video Options.