when I put the frozen dark red dahlia flowers into the water, the dye leaked out immediately (I think that India Flint is right in commenting that freezing opens up the plant cells, so that the pigments are released faster!) and gave off a lovely strong red.
I simmered the flowers very lightly and because they turned very pale and mushy, I strained them out with a fabric nappy, pressing out all the liquid - the nappy turned strong yellow, light orange - very promising indeed! I have dyed with dahlias before, but my smaller ones with strong red flowers didn't flower at all this year (I think I have to take them out of the ground and divide them?) - the first dyebaths all ended with a very strong orange in the first batch and gave a lighter golden yellow in the exhaust. seeing the very dark orange bath and the orange-brown dye on the fibres (wool and silk) left me hopeful; I left the bath to cool over night.
if I had intended to spin tussah silk, I would have bought it straight away in that colour. why did I spend money on lovely mulberry silk if it looks like tussah after dyeing?:(( and where did the lovely orange go? not into my wool and silk, that's for sure! well, that teaches me a lesson! no, two actually:
I will have to grow much more of the normal red dahlias, which gave me orange and yellow last year and before that! and maybe I have more success with the very dark red dahlia if I use it frozen and press (or hammer:)) it into pre-mordanted fabrics? the plant still flowers so I'll probably be able to try the latter out in a little while. for the first lesson to repeat I have to be more patient and wait another year:(( but on the other hand - maybe I'll be able to find a few more of those clear red pompoms - in the hope that they all give off the same nice orange!