It's way easier to go to a darker color from a light one than it is the other way around.
I've never used Colorbond. Can't vouch for it.
My dye of choice is SEM. Been using it for years. Never had probs with it when applied properly.
There's no dough in doing projects 2x. Never had a come-back with SEM.
Fabrics in a vehicle are man-made. Leather being the exception.
Nylon. Olefin. Polyfin, Vinyl, etc.
That means that those fibers that make up the material are very slick. Non-porous. The material is used in vehicles for that very reason. Dirt & stains have a hard time glomming onto the individual fibers.
Non-fabric solid materials are more susceptible to dying as you're only having to deal with a single surface.
Fabric is a multitude of surfaces.
So...the dye has to worked deep into the fabric in order to reach every individual strand.
That requires either:
-Light coats of the dye, brushing the material between each while the dye is still wet, getting it right down in there to the base.
Just spraying the dye at the material & it'll only sit on the tips of the strands. Don't get it down to the base of the fabric & as the material moves around through normal usage it'll all start to look blotchy.
Then, the material'll need to be brushed again when it's dry because the dye will cause the fibers to stick to each other. They need to be broken up.
Laying the dye on the fabric in a one-shot heavy coat. Basically, just drenching the material. Still requires brushing, but done several times as the dye dries.
Have to watch the surrounding vinyl/leather bands when doing this method as drips in the dye can not be worked out of those materials.
With either method, an adhesion promoter is mandatory.
And after all that, I really, really don't like to dye fabric seats.
The end product is never as nice as the original.
The material looses it's soft touch. Ends up with a slightly crispy feel.
Because the individual fibers are so soft before being dyed, they are working around against each other when sat on. Dye makes those fibers thicker & crispier creating probs with flaking where the promoter maybe didn't get full penetration.
O.K. After a bunch of inquiries, I'm gonna attack this once again. Had it nearly done once, only to hit the wrong button before I hit 'Post' & deleted all of it. Had to start again! Grrr! #@$%$#&$!!! Almost threw something! This info is from my experience. Others may have different techniques...