I recently started experimenting with forced patinas. I used a carbon steel Mora 711 for my first experiment. I wrapped it in a paper towel soaked in Tabasco and let it sit overnight before rinsing. I didn't get a patina on the whole blade (some parts must have been left uncovered), so I wrapped it in a paper towel soaked in concentrated citric acid and let it sit for an hour.
After rinsing I was a bit more satisfied with my knife's patina, so I decided to do a sharpness test; it had lost most of its cutting ability and could only slice paper, not push cut it.
I decided to try and restore it on my Fällkniven DC4 and I achieved a hair whittling edge, but because of the blade's geometry (flat grind in the same angle as the cutting edge through half the width of the blade) I had polished off most of the achieved patina.
I got impatient and wiped the blade with a paper towel with a bit of nitrating acid (concentrated nitrous acid + concentrated sulfuric acid). This left me with a rather plain patina and an even duller edge.
I decided that I'd been too rash. I polished off most of the patina on both the edge and the sides, restored the edge and wrapped the blade in a paper towel soaked in a Tabasco/mustard/red wine vinegar mixture and left it for an hour. The patina lacked the character/darkness I sought, so I stuck it in an orange for an hour hoping for a better effect. After this I still wanted some darker spots, so I dabbed the blade with a paper towel with some nitrating acid on it and waited until I was satisfied with the color of my patina. Dabbing created some nice dark spots, instead of just wiping off a layer of metal and leaving a smeared, plain patina.
Finally, I rinsed my blade with water, scrubbed it with soap and a soft brush, rinsed it again and dried it. Then I put some WD-40 on it.
In the end, I was more than satisfied and I've learned a lot about forcing patina's.
TL;DR: I gave a Mora 711 a three layer patina consisting of a vinegar patina (plain), a citrus patina (by sticking it in an orange, irregular pattern) and some darker spots (by dabbing it with a paper towel with some concentrated acid on it).
Also, Pics will follow later.