What would be the best way to achieve a ombré or watercolour effect on fondant without an airbrush? Similar to these:
I’ve done a sunset effect before by painting with gel colour mixed with vodka. Would dry petal dust work? Or petal dust mixed with alcohol?
what I would do is get my cake cold because I know just how much condensation will come up on it when I take it out and I would brush on dry powder -- although the second picture looks like buttercream
I know you were just giving examples
I think the first picture could be achieved by dry brushing powdered colors, as -K8memphis suggested. Personally, I would do it before refrigerating so the fondant would be dry, maybe even let the cake set at room temp for an hour to allow the surface of the fondant to skim over a little. Wilton makes spray cans of edible color that you could use to get the artbrushed effect. I've used them and they work well, but do not go very far.
The second one definitely looks like buttercream and is beautiful.
I’m a bit confused about your comments on refrigerating. Do I need a bit of moisture to get dry powder to stick? I assumed too much moisture would cause problems.
The second cake is beautiful and is definitely buttercream but I might have a go at recreating something similar on fondant. I don’t know if I can get neon colours in the uk.
My intention is to use these as a background to some silhouettes (of a horse jumping and some fences). I wonder if it will be too busy.
You do not need moisture for the powder to adhere to the fondant. It will be hard to keep it from streaking and blobbing if the fondant is moist. I will like it dry and even dryed out a bit on the surface.
I think it would be a beautiful background for a jumping horse sithouette. Depending upon the time of day for which you are shooting, the bottom could be a dark green and browns, grading upward with lighter green, then turning to blue for the sky.