http://weddings.theknot.com/Real-Weddings/88730/detailview.aspx?type=3&id=88730&wedding+details=cake

I have a bride wo sent me this pic and for the life of me I can't figure out what exactly they did for the coloring.
The cake is buttercream, and that is what the bride wants. It almost looks like they used a wood grain tool, but on buttercream? Is it possible?

My guess: It looks like buttercream not completely smoothed out that they used a technique called dry brushing with the brown and black coloring. Using a ragged edge wide paint brush (much like the chip brushes) load with thinned food coloring and pull some of the color out on a paper towel then brush (very lightly) the side of your cake with the brush. Do a small patch of black randomly around. Go back over with a dark brown. Then pipe with icing the stripes of black from your buttercream or royal icing. Good luck. If I explained myself well, if that is not how they did theirs, you should be able to get a similar effect.

Beautiful cakes on that site. Thanks for posting the link, another great source for ideas.

Maybe they put food color on the wood grain "stamp"? I don't know

The site won't let me in w/o signing up. I don't plan on ever visiting again and won't sign up for span

I have seen this technique used on one of Colette's cakes, although the technique was done on modeling chocolate. In her book she said to "score long and short horizontal slashes with the tip of a sharp knife. Mix black powdered coloring with lemon extract and paint the marks."

It is very possible to do this technique on buttercream. To me it looks like the technique was done with a wide paintbrush. I would make sure the buttercream on the cake is ice cold. Get some brown or black buttercream and thin it significantly to where it is watery like acrylic paint. Take a new, wide (dry) paintbrush which is very soft, and dip it in your thinned buttercream. Wipe it on a paper towel to remove most of the buttercream, and very gently drag it across the cake. You want it to be faint so that's the purpose of wiping it on a paper towel. This is kind of like dry brushing in art (I used that technique very frequently to paint those porcelain Christmas villages and stuff when I was a kid). Here is a brief article:

http://en.wikipedia.org/wiki/Drybrush

To make the darker lines, I would come back in with a fully saturated brush and just paint it on. Again, make sure your base coat is nice and cold.

Annie

Oh snap I wished I had read the replies. Grandmomof1 has it right!

I can't see the pix either.

I am doing this cake for a bride, too. I flat out told her I didn't know how to do it in buttercream, so she will be happy to hear that I can. Thanks for posting.

It looks like a printed image to me.

Thanks everyone! I am meeting with the bride today, and I found another design that is from Jaques Pastries that uses buttercream with a gumpaste strip attached that looks like it's "buttercreamed" on to the cake, so I'm going to try and convince her to go that route.
However, if she sticks with it, I think a paint brush with cold buttercream and coloring is probably right on.
Thanks again!!