If you want bright colors, you'd better choose crayons with similar colors.

Melt the white candle and crayon together. During the melting process, the ratio of white candle to crayon can be adjusted appropriately. If the color is too dark, add some white candles, otherwise add colored crayons. Until the color reaches your satisfaction.

Because crayons contain wax, their colors are brighter than pigments and pigments.

You can try.