It looks to me like they used lace cutters/impression mats and painted the gold on.
Where did she/you get the pix? Can you ask the creator of the cakes for help?
Painting it on lace impressions would work for the grooms cake but the brides cake is gold on red background.
I'm wondering if it's not real ribbon?
OR you could make red ribbon strip then use a stencil to brush on the gold.
Hi. i have seen this type of thing before and yes its gold painted onto fondant. as for the red ribbon its red fondant with piped detail then the piping is painted very carefully by hand with gold. good luck with it its a stunning effect, unfortunately my hand is way too shaky for that kind of painting.