I continue to do dyeing experiments, changing one variable at a time to see the different effects. I did these two this past week. All samples are fat quarters of muslin.
For the set on top, I used Procion chartreuse and lilac. Both pieces were loose folded on the diagonal, and the fabric was dry to start. The sample on the left had dyed applied to it first, was left to set for 45 minutes to an hour, had soda/salt solution poured over, and then batched for 24 hours. The sample on the right had the soda/salt solution applied first, was left to set for 45 minutes to an hour, the extra solution was poured out of this tub and into the first tub, then the dyes were poured over and left to batch for 24 hours.
For the second set I used Procion electric blue and Sabracron purple. The two batches were processed exactly as they were in the first set -- EXCEPT that the fabric had been presoaked in warm water for 30 minutes, then wrung out. Then I proceeded as above, the left sample getting dye first and the right one getting soda/salt solution first.
As I've found in earlier dyeing experiments, there's really no resulting difference in starting with dry fabric or with presoaked fabric. The primary difference is in when the fixing is done, either before adding dye or after the fabric has sat with dye on it for a while. The dyes comingle more when added to the fabric straightaway.
A note on wetting fabric beforehand: some folks recommend it and some folks don't. Why am I not surprised! In theory, if you wet fabric first, then the dye sites are taken up with water and therefore unavailable to accept dye molecules, meaning there will be more white or undyed areas on the fabric. But also in theory, if you wet out fabric, then the colors wick more readily, meaning you get potentially better coverage with the dyes. As with everything else, it boils down to personal experience.
I actually like the effects I get better with prewetted fabric, although I only do this with low water immersion and direct application. If I do a regular immersion-style shibori dyebath, then I'll start with dry fabric -- primarily because it is much easier to manipulate dry fabric than wet fabric. The volume of water in the dyebath, though, pretty much guarantees that the fabric will get wet through and through.
There are so many variables to consider with dyeing, which I think is why I'm so intrigued with it. There are so many options to play with, so many possibilities to try out. And everybody seems to have different experiences because of a multitude of environmental variables. Thus I've concluded, in the end, to each her or his own.