Dark etching

[nurseswim]

I see very few SA , NSKK, etc daggers with dark letters etching.
Is this just simply worn off most daggers?
Dark etching increase value of the dagger ?

Please advise and thank you from a new collector

[Schlange]

Black etching is mainly introduced during the later period of blade production in TR.
Examples: Late RZM Puma Solingen SA daggers of navy Carl Eickhorn KM daggers.
During the production of most of early SA dagger Solingen company did used "unpainted" type of etching.

Schlange

http://www.mojalbum.com/schlange88/albumi

[fredswiss]

As Schlange pointed out, most early SA daggers do not have "dark" mottos but there are exceptions. Here's an example of an early SA with a dark motto:

[fredswiss]

Here's a view of the back. As you can see, the maker's mark is also dark: