Sample Texture2d (lod) node maps texture color to wrong vertex position

Hello,
I made a vertex shader graph to display a surface, where the y coordinate (i.e. height) of each vertex is
set by a height map (png file). Now, I have made a very simple png file.
I encode the height over the red color channel. The value increases linear in one direction (see image).

Unfortunately, the surface height does not increase linearely. Instead, it seems to increase
exponentially or according to a power law (see second picture).

200323-screenshot-35.png

Seems, that this is caused by the sample texture (lod) node. It seems to not just map
the red color channel directly, but instead make some exponential change with it.
Do you know, what I did wrong? Is there perhaps a certain setting, that I have to change or
a mode, that has to be set or some checkbox, that I have to tick?
For any suggestion or help I would be very thankful.

Hi,
I know this is old but I just came across this by chance. The reason for that is most likely because you’re using sRGB in the texture. If you untick that from the texture properties you’ll most likely fix this.
sRGB values are decoded using exponential values which is why you see the curve.
Hope this helps,
Eduardo