Normal map seams in Arnold

[Anonymous]

Hello, I come from Blender+Substance and I need to make renders in Arnold. 

This object is been made and rendered correctly in Blender, with regular Substance outputs. I'm using a 24bit (figures as 8bit on photoshop) openGL normal map. 

Now, as beginner in Arnold, I'm not getting a correct result: you can see there is a seam on the heads, that's where the UV seams are. (I am using an Arnold light and I'm rendering with Arnold).

But I saw elsewhere, in many cases, the normal map being set in this way in Arnold (and working) so I did the same:

But I get that result. If I connect the bitmap to the "normal" socket it's even worse. 

I don't want to add additional nodes here, but mainly to understand how to make it work correctly with its most basic setting, like this, perhaps changing something in the input image if it might be the problem. I need to keep the workflow minimal and just to be as it's supposed to be in the usual way, because it needs to fit in a pipeline and I need to make many renders of many objects with the same workflow.

Other details: yes the normal map node is set to Tangent space, and Color to Signed is flagged. Order is XYZ and the image is not rotated. I'm using Max 2019.

[oliver · Accepted solution]

Turn off gamma-correction (override with 1.0 / set color space to linear) for the image.

This can be done in the import-dialog (autodesk bitmap-node) or in the node's settings (OSL bitmap lookup & Arnold image-node) .

[Anonymous]

It worked, thanks a lot. I imported them bitmaps before by drag&drop so I missed the importing settings in between. That means, by drag&dropping, it corrects gamma automatically.

Thank you!