Beetroot juice

Good point Wazz. Mordants are more about fixing dye so it won't wash out etc.

As for colour retention vs oxidisation, that is a question we will have to wait for the answer for..

Before I took to Luthiery full time, I was a Stonemason.
I had a restoration job on a heritage building in Sydney and the mortar was a pinkish brown.
Never saw that before in my life, I initially thought they had used a pink sand but on closer inspection I saw it wasn't the sand..
Did my research (asked an old timer Stony) and discovered the mortar was probably stained with Ox blood!!!

So off I go to the local slaughter yard and got a 20litre drum to run some tests.
When fresh the mortar was pink, but over a few weeks it changed to the pinkish brown due to oxidisation so your question about colour fastness is a beauty :)

I wonder if there would be better success with a sliced whole Beetroot as opposed to canned or the juice from canned...
Fully untainted then and you are using the pure juice, you could use a smaller beet cut in half and rub it in

I did 2 woods, marine ply and a hardwood in 2 colours, red and blue.
This is the result of dyeing then sanding marine ply. I overlapped the colours to see how they would blend.Attachment 8366
Nothing exciting. The wood does not like to take stain.
Attachment 8367
Sanding did not improve the look.

Plywood seems to be a denser timber, as its manufactured for strength, which will make it less receptive to dyes. It still gives an idea on colour, though.

Here is the hardwood. It has a few remnants of black and red ink after I sanded it. Most of the ink, a previous attempt at staining, disappeared. The dark is shadows, it was late afternoon.
Attachment 8368
Here is the wood dyed red
Attachment 8369
This is after sanding back vigorously this morning. I wanted to make sure it was not just a film on the surface like most of the ink had been.
Attachment 8370
And finally what is looks like wetted
Attachment 8371

Much better than the ply. You need some grain to hold the colour.

Last version was blue on hardwood.
When I first dyed it late last night it looked black. I was thinking OMG I have gone too far. Dried lighter.
Attachment 8372
After sanding the grain reappeared.
Attachment 8373
It looked good wet
Attachment 8374

Just to show there was a chemical reaction between the dye and the wood here is a picture as the water was drying. You can see the colour is across the full piece of wood even after sanding.
Attachment 8375

I guess if I went over the top of the blue with a red dye I would get grades of red and purple.
The dye I used is Tulip tie-dye. You can get it at Spotlight (expensive) or Riot Art and Craft (cheaper when I bought it in December). And just so you don't die wondering here is 1 of the 10 t-shirts I did. Shibori method.
Attachment 8376

really interesting to see those results, and how well it soaks in.
shirt looks cool!

cool tests you have done Open Gman !

the shirt does look cool and some interesting colours you got !

As it happens SWMBO was cooking some beetroot from our garden as I read this thread.

What else is a guy to do?

I grabbed a piece of pine and the scraps bucket.

I gave the pine a very quick sand, just to key the surface.

I simply rubbed discarded pieces of the boiled beetroot onto the pine (and scrapped off the vegetable matter that stuck to the rough surface).

The images were taken a few minutes after, as a control:

Attachment 8378

Attachment 8379

Hi Col, can you post a photo after it has been left to oxidise for say a week or two as I suspect it will go slightly browner over time unless cured somehow.