Walnut Ink

I am determined - I am going to do a silk screen print with home made walnut ink.
 So far I have tried two mixes of colour extracted from the green walnut husks I gathered on campus at Moray School of Art. The first try was far too liquid; although the colour was good and intense it just ran through the screen into puddles on my paper. So then I tried mixing some with acrylic silk screen medium. This worked to an extent, but the colour was too pale now.

So I have spent the evening pulverising more husks in an old coffee grinder, soaking the resulting powder in a wee bit of water then straining the dark juice out with a sweet old tea strainer. Although green walnuts (husk and all) are edible as a pickle, I am being cautious and only using tools and equipment that I reserve for dyeing.
I have the nearly full enamel milk pan simmering on my wood stove now to try and reduce the walnut ink down and make it thicker and stronger. It smells rather interesting! I'm not sure if I like it or not....
If this simmering doesn't make my ink thick enough, I have plans to try thickening it up with corn starch or gelatine, or even seaweed! Lets hope tonight's experiment works - I'm running out of time, we only have three more weeks before we have to hand in our work for the printing block!