Before you order any of these chemical patinas for use on the SW SS media it is important to understand a few things. First, this print media is a composite mixture of stainless steel and bronze, being about 60% ss and 40% bronze. Chemicals designed to color plain carbon steel will have no effect on this material. This would include solutions referred to as "gun bluing". There are some formulas designed to work specifically on stainless steel but results on the print media were not very good.
The chemicals that work best are actually the ones intended for coloring copper alloys. These are available from many sources all will produce similar results with colors ranging from shades of brown to deep blue black. The best product we have found for producing a true black color on the print media comes from the Birchwood Casey Co. I believe the product is known as A-24. You can check their website to confirm this.
The other thing folks should realize it these chemicals are rather expensive and in the US extra hazardous shipping charges will be tagged onto the mail order ($20.-$25. extra) per shipment!
You might be able to find a Birchwood Casey "Brown finish for Brass" in a shop that sells firearms and save the shipping costs. This produces a very dark brown color, almost black.
The other thing to try is to experiment with heating techniques mentioned in another one of my posts. This is FREE, no chemical hazards and with practice works VERY WELL.
-G