What would be the correct way to blend 2 normal maps together?

[Jpjapers]

I have a fabric normal map and a wrinkes normal map and keep finding myself needing both.
What would the correct Gamma and blend mode be to mix them properly?

[romullus]

In photoshop we use overlay to blend multiple normal maps, so the same should work in 3ds max too.

[Jpjapers]

In photoshop we use overlay to blend multiple normal maps, so the same should work in 3ds max too.

Would I need to load them gamma 1.0 yes?

[jms.lwly]

The Corona Material library actually has some materials with blended Normal maps (e.g. Fabrics).

They tend to go Bitmap -> Mix -> Corona Normal -> Triplanar (if required)

[maru]

I think just blending them with 50/50 transparency should work fine, without any special blending modes.
Gamma should be the same as when loading just a single bitmap (so the brightness of the flat blue areas should not change).

[Ricky Johnson]

There is supposed to be a technically correct method that requires treating each channel separately.
Lots of guides are available for different applications - Like this one: https://www.moddb.com/groups/udk-developers-group/tutorials/photoshop-combining-normal-maps
I don't know if the same set up could be replicated within a material in 3ds max - it would be complicated. The blend mode overlay always looked okay to me for a simpler set up.

[Jpjapers]

Thanks for the information everyone :) I would have thought using a 50/50 mix would half the intensity of both maps overall so the strength might need to be doubled. I have an idea on how to do the photoashop method in max. It might be complete overkill and yield the same results but damn its got me curious to see if it can be done.

[arqrenderz]

I make a  corona normal and in the additional slot i put another corona normal map (is it bad?)

[romullus]

I make a  corona normal and in the additional slot i put another corona normal map (is it bad?)

My feeling is, that it's really wrong, but it would be interesting to compare it to overlay blending method and see how it looks.

[mantaskava]

Until recently I've just mixed them both with 50/50 (maps loaded as gamma 1) method and after that bumped up the strength from default value of "1" to "2" to compensate for the loss.
But now I got confused after watching some of the Adan Martin videos. Where he's disabling one's of the maps blue channel before mixing them, link to that video (and exact part) here- https://youtu.be/vAHLNq77jUs?t=1849

Anyone has any explanations/comments on this?