Sorry if this has been posted before.
I have been sorting out my lego and putting it into containers by part and colour and putting them in rebrickable and also excel
my problem is that I have bought lego from bricklink and also bought models
both parts I am looking at are dark bluish grey, Technic, Liftarm 1 x 11 Thick. when I came to put them together and in the container I noticed they are not the same shade one is slightly darker
is there different shades of one colour? slightly confused on this