These are also known as powdered dyes. Because of their powdery forms, they need to be allowed a little time to dissolve. They should be added to the wax at about 176 to 180°F. Dye flakes do not give the kind of consistency that liquid dyes afford. It is not as easy to get exact proportions in different candles especially when making them in small batches. This is why they are more suitable for large projects where they would be added to the wax at once and used to make several candles. They are also used to make candle chips and blocks.
Dye flakes are very concentrated and just a little would go a long way. Just like liquid dyes too, you add as much or as little as you want based on the colour you want to achieve. The weight of the wax also plays a huge role. For a more consistent colour, especially in making few candles, you would need to measure your flakes as a percentage of the amount of wax you are using, in grams. Anything between 0.1 to 0.25% is okay. Measure your wax in grams and multiply it by desired percentage. The result of this is the amount of grams dye flakes you need. Going by that calculation, a kilogram of wax would need 1 to 2.5 grams of dye flakes.
Dye flakes are very easy to use. Simply add to the wax and stir very well for better bonding.