community of dyers

I was surprised to see how distinctive the change in color was when I added soda ash to ProChem's Boysenberry MX dye (which I believe to be reactive violet 13, or magenta MX-B, not violet MX-BR as described by ProChem). It went from a pinkish red-violet to blood red!

In the picture above, the bag on the left contains dye in just plain water, while the one on the right also contains half a teaspoon of soda ash, in a volume of half a cup (2.5 ml in 125 ml). It also seemed weaker in color, and the dyed material looked very pale, but after the washing out step, when the pH returned to neutral, the color returned to normal, too.

I was using some very old boysenberry dye, mixed up in late July 2006, and stored since then in the refrigerator, so I was not surprised to see that it was not very bright on cotton. It's old enough to show some weakening, though it still worked great as an acid dye. I mixed up some fresh so I could have propr comparisons. Here are my results of dyeing the multi-fiber dye test ribbon:

On the left is a swatch dyed with old dye and acid (15 ml of vinegar in 125 ml of water). The second swatch from the left was dyed in plain water. The third swatch is the old dye, applied with soda ash, and the rightmost swatch is fresh dye with soda ash. I did not steam properly, just heated the dyebaths briefly in the microwave oven until very hot and steamy but not yet boiling. Cotton is the topmost colored band, the fourth band from the top, showing some staining even with acid; it dyed well only in the rightmost swatch, with fresh dye and soda ash. Nylon is the next colored one for the acid and plain water swatches (our water is a neutral pH of 7), the eighth from the top; it stayed perfectly white at basic pH. Silk is the next colored one below that, tenth from the top and fourth from the bottom. Rayon is second from the bottom, and wool is on the bottom.

It's interesting to see that boysenberry dyed silk well at an acid pH, or at a basic pH when it was fresh, but the old dye did not work very well on silk at the basic pH (with soda ash). Old dye works on silk only in the presence of acid. Fresh MX dye works well on silk either way, since it can act as a reactive dye on silk. This dye did not do so well on wool at a high pH. This is something that varies markedly depending on exactly which MX dye you have. Some MX dyes work great on wool with soda ash—the only problem is the damage the high pH does to the wool.