If i dye this jumper will it come out marbled effect?

[dudsville]

I bought a jumper, a nice big slouchy thing from the white company. I've worn it so can't return it but the colour doesn't suit me. It's a very pale grey. The material is 40% viscose, 30% nylon, 30% merino wool. I'd like to try a dark grey dye and I know the merino and viscose wool take the colour well. I've never dyed nylon, I think its a separate dye product. Has anyone ever dyed a fabric mix like this?

I think that when yarns are mixed like this, the fibres themselves are mixed all along the length of the yarn. Does that make sense? So you’d get a sort of marle effect.
The wool I think you’d have to wash in hot water and proceed with caution (shrinkage). Not sure about viscose but the nylon will definitely not dye with the wool dye.
If I were you I would aim for a pale colour that will suit you rather than aiming for a dark one. Pale blue or green? Or a medium grey?

That makes sense ghost, thanks. And a medium grey would work.

When I’ve done that the overall colour comes out lighter than indicated on the packet but it’s evenly spread, except for any stitching which is invariably synthetic so doesn’t take the dye. If there’s any wool at all in the fabric I use a hand dye as the machine process seems to fluff it up.

The viscose should take up the dye well, but will be less intense than the wool. The nylon won't take it up at all. As Floisme says, the stitching will also remain undyed.
I'd expect the final result to be well worth it.

Thanks both, I'm looking forward to seeing the effect!

Update! Surprisingly the whole of the jumper took the colour even, bizarrely, the stitching. I suspect the fabric content was somehow mis-reported. Glad I took the plunge.

That's what I love about dyeing - you never quite know.