Hi Sean, I checked out your site and I would say you would know if your machines are not getting penetration just from experience, so I would suggest you use a different black. Looks like someone has made the black without dispersing it properly, like mixing a carbon powder with the carrier liquid by hand or something. Carbon's are very hard to disperse and this looks exactly like un-dispersed Carbon, you can not see the difference in a bottle side by side of good dispersed black and un-dispersed black as they will both look ok. But if you want to get a good look at it you need two pieces of flat glass, put a drop of the black you are having problems with on one and half an inch away put a drop of black you know is good and then gently lower the other piece of glass on top so it presses the two drops out until the edges touch and at that point I bet you will see a big difference, with the poor one looking very grey. You need to do it in good sunlight as you can only see the effect for a second or two until they merge.