Well now I'm intrigued. I pulled out the 'solar dyed' skein and rinsed it out. More of a 'want a look' rather than any surety that the dye had taken. I rinsed it out....not much dye came out....good...
As you can see, the left is the heated with strong bits of colour, fairly well defined, the right skein is the solar dyed, the colours have mixed in alot so it is uniform and 'muddy'.
I did not expect this as I had done the two skeins at exactly the same time with what I thought were similarities in both technique and dye quantities. However, it was not a scientific test, and this result suggests that I should do another lot!
I have some commercial yarn, crying out for change in colour, I'll just have to sacrifice that to the cause!
Using the heat of the oven after cooking and turned off, what a good idea, though that does suggest I cook! Further suggestions for 'free' heat are gratefully received.