Many people “bloom” their dyes. This simply means adding liquid to dye powders and then basically dyeing your bicarb. Water is the best choice because you will get maximum results being that these are water-soluble dyes. With some colours, alcohol can morph and change the look of the dyes. With blooming, you can get the most vibrancy without the fear of activation because you’re letting the mixture fully dry before using it in your recipe. With black and red as mentioned above, it is recommended that more dye is used, but also water with hot water being best. It will help dissolve the dyes better and adding more water with this colour will bring out more vibrancy. Remember to mix very well, the more you mix the more the colour will develop. It is recommended that you sift your bloomed bicarb before using because it can dry clumpy. Simply use this the same as you would uncoloured bicarb in your recipe.
These are the hardest colours to get a rich intense colour using only water-soluble dyes. This is because you are starting with a white base so this instantly turns these into pink and grey. Because these colours are normally wanted in dark/solid it is recommended a higher use than the other dyes.