In my quest of blue-black inks , I have acquired Parker Quink blue-black (latest formulation ), Pelikan 4001 blue-black (earlier version) ,and Pelikan 4001blue-black (latest version) ,and found none of them satisfactory to my visual appeal , I mean the "exact" blue-black for me. However, Pelikan latest formulation was closer, but not entirely satisfactory. Therefore, I decided to mix parker blue-black (present formulation) 3 equal parts with Parker black (present formulation) 1 part. These were bottled inks, no cartridges. I am presenting my result as a very informal and personal review for comments by fellow FPNers .I may not be the first one to do this. Sorry for my poor camera work.