Why do natural colors look more pastel or muted compared to synthetic dyes?

This is an inherent characteristic of natural pigments rather than a quality issue. The chemistry of plant-based pigments produces a different range of achievable color intensity than synthetic dyes, which are engineered specifically for brightness and stability. Natural colors tend toward softer, more muted tones — especially after heat exposure — and this is simply the trade-off that comes with choosing a clean-label, plant-derived colorant.

In most applications, the result is still attractive and clearly visible — it just looks different from the neon tones a synthetic dye would produce. If you're making the transition from synthetic to natural colors, adjusting your visual expectations and your customers' expectations is part of the process.