Dying with black food coloring

I got a small bottle of black food coloring to try on some silk. I put half of it in a pan of hot water with a smidgen of dish detergent. I put the silk in and let it heat for a while and then let it set. When I rinsed it, it was this beautiful blue color. The picture does not do it justice.

Using the same dye, I added a little vinegar. The silk isn't dry yet but I'll publish a picture of it when it is. It is a dark blue green. I added more water and the remainder of the food coloring. I put the third piece in this, let it heat and set, like I did the other ones. It is a turquoise color. Then I put a little vinegar in the dye water and put my last one in. It is still in the pot but, so far, looks like it has some red in it. I put some wool in the last batch to see what it would do.

I'll add pictures of the last three after they are dry.

The second picture is a better one of the last silk I dyed in the Muscadine juice.