As soon as I saw 'dcwaites' Ink Blend Evaluation form, I had to print it off and complete it after it spurred me on to produce my own copy of Pen & Message Cigar ink. I have been trying to produce this copy for a while, but I couldn't do it because I was using a washable blue element that made it fail. So I selected a bottle of Noodler's Bad Blue Heron and started again. The permanent blue element doesn't have to be Noodler's Bad Blue Heron. However, it does have to be a permanent, waterproof, single dye royal blue type ink. The green I actually used in my recipe isn't available as it was a potential Diamine Green shimmer ink that didn't make it to production. However, I'm reliably informed that Diamine Jade Green or Light Green will work as well. In fact any washable bright yellowish green might work. The chroma test will separate 3 dyes for you to replicate: Permanent blue, terracotta and bright green. You can only replicate that chroma test if you use a permanent blue ink. If you don't the blue and terracotta will mix and make dark brown.