I would like to point out that the traditional Brit method of using Alkanet is with the oil of the Flax Plant. It was not come upon by accident but by years of trial and error and to put it succinctly they go together like bullets and guns a marriage formed over time. Alkanet steeped Alcohol is something of a more modern method of obtaining the colour, I feel the jury is still out on this.
Because Alkanet has been used here in Brit Land for such a long time there are a few less known methods devised to adjust and change how it reacts and colours wood.
So try this to darken its effect add Antimony Trichloride sometimes known as “Butter of Antimony”. Add small amounts at a time to the Alkanet/Oil mixture and check the colour change but it all takes time to show, and this is not what we want in our modern world we like things to happen instantly.
