(this refers to the normal material nodes, not cycles. It is also unrelated to the texture node system)
the color of textures used in a material node tree differs from other uses, the texture appears to be much brighter possibly using a wrong color space. Is there a known fix or workaround for this? The screenshot below shows a normal map. The left side is the node view (it also comes out like that on the output node so it is not just a display issue) and on the right side is how the texture normally looks in the image editor and otherwise.
edit: added a sample blend texture node.blend (1.59 MB)