Let’s say we have this texture metal taken from CGtextures website:

It is possible to perceive the difference of light across the texture and that becomes even more noticeable when an Offset filter is applied:

There are at least two options to remove or attenuate this difference of brightness.

1st technique – Average/High Pass to remove highlights

• Open the texture in Photoshop and duplicate the layer. Rename the layer to Average.
• Apply the Average filter to this layer. Filter>Blur>Average
• Duplicate the initial layer again and rename it to Linear Light 50%
• Place this layer on top of the Average layer
• Change the Blending mode to Linear Light and reduce the opacity to 50%
• To the Linear Light 50% layer apply the High Pass filter. Filter>Other>High Pass…
• For this image a radius of 100% worked quite well, but each texture will require a different radius. A useful tip is starting with…