ok so i will be using buttercream icing and i want to color it silver & gold. what color food coloring do i use? thank you all

You won't be able to get true silver or true gold from food colour alone. The best thing to do is colour it grey for silver or yellow for gold then airbrush it. If you don't have an airbrush you can buy cans of metallic food colour spray... PME does a range.

Failing that you could try adding lustre dust to the buttercream ie sprinkling on, blowing on, splattering on with a new toothbrush etc, but you won't get any effect if you mix it into your buttercream. I doubt that would work very well though so your best bet is the airbrush or sprays.

If you have an airbrush....the silver and gold sheen colors would work.

If your buttercream crusts, I think you could paint it on with a mixture of luster dust and vodka. I've never tried it myself but I read it on here a while back.

You can brush the luster dust onto crusted buttercream with a dry paintbrush. You'd want to color the buttercream yellow for gold or gray for silver before you add the dust...the silver especially just looks like dirt when you put it on white buttercream (ask me how I know ).

I am not sure if this is what you are asking but to get gold I used golden yellow and added a little brown until I got it just the color I wanted. To make silver you would just use a little black in your white buttercream. Of course that is also gray...but that's the only way I know to get the gold and silver just using the icing color. Hope this helps.