a brush of orange...

so... this is close to what i was trying to do... a gazillion thanks to Babs (@onewing) for pointing me in the direction of the brushes i needed... which can be found here:
https://www.brusheezy.com/brushes/1990-free-hi-resolution-paint-stroke-photoshop-brushes

i think i need to do a bit more experimentation with this so expect to see more mucking about with paints over the next few days...

just so i remember more or less what i did...
1 - i reduced the image size by a LOT as well as converted to 8-bit... i may have gone further than needed...
2 - after adding the brush stroke on a separate layer, i made a copy of the layer... for one layer i used the colour blend mode, and for the other i used normal, and then reduced the opacity a bit...

[Kingston Road Creative]

super cool, nice work

[Annie D]

great work - I love the concept - thanks for sharing

[Graeme Stevens]

great concept, like it a lot

[diane day]

very cool effect

[Rosie Kerr]

This is an excellent effect. I read your question, but had no answers. Glad that Babs could help. Very illuminating!

[Amy Shaylor]

Great effect. Looks good.

[Babs]

Oh this has worked so well. fav.

[Sheralee S]

Fantastic, love it!

[Joan Robillard]

Gosh I just choked laughing

[Adi]

Are you going to be ok with putting colour? lol :)
Thanks for sharing the link

[Jocasta]

wow - love the processing

[Marnie]

Very clever, love it.

[Cathrine Mitchell]

Very unique indeed. FAV