Thinking through the three dyeing sessions so far, I am disappointed.  In spite of adding more dye mixture each time to the soda/salt solution the tone hardly varied.  It could be a number of things: quality of the dye, the fabric, human error.  I didn't think using the same recipe and instructions again would get me anywhere, so remembering a workshop called "Dyeing for the Terrified" with Yvonne Brown I dug out her notes and put them to the test.  I sent for Synthrapol (for the final wash) from Art Van Go and had a really helpful discussion with Janice, who advised finding a really good dye recipe and sticking to it.

First I made a set of tonal samples.  So far so good.

Then I tried applying the strongest mixture to more prepared stitched Shibori pieces, soaking them in the soda/salt solution and then applying the dye with a syringe.  They were, of course wet when the dye was applied, cold that explain the stronger colour -- not according to the module notes, instead the patterning should be softer.  The colour too?

Zigzag Machine Stitched.

Cross-hatched Machine Stitching.

Wavy Vertical Lines Machine Stitched.

These three samples have the tonal range, movement and markings I had hoped for.  I also feel, though I've yet to put it to the test, that I could recreate any tones within the sample range.  Such a relief!  Still more work to do, but this is better.  Maybe it's my greater experience which is evident.