It's been a long time since I did it but I think what I used was similar to what damascus described, with India ink. It's held up well for years on my Fox BE grade. As damascus said, the level of background darkness can be controlled. I chose to keep it very subtle on this 105 year old Fox.

Before:

[Linked Image from jpgbox.com]

After:

[Linked Image from jpgbox.com]

[Linked Image from jpgbox.com]


May God bless America and those who defend her.