Just wondering what types of product you use to get the yellow colour on the inside of the lily like the one pictured below. I also have to make rose in the pink colour inside the lily. I use americolor gels, what would you use to mix this colour up?
(Attaching your picture in the message so it's easier for others to see)
Usually, lilies made from gumpaste are white, and then coloured with petal dusts after drying them. I have a couple of sets from Petal Crafts that have a whole bunch of colours in each, and you can blend colours together to get the right shade.
If you are making a rose in the same pink as the lilies in your picture, I would colour your gumpaste a pinkish colour with maybe a touch of violet, then dust the rose with a dusky pink colour.
You'd be better off getting some petal dust or powdered food coloring. What the other poster said is right on.
Dust the color on (both sides of the petal leaving a 'hole'/space at the bottom of the petal for the yellow color.