Is twilight a redness or a whiteness?

Twilight is the redness that appears on the horizon from sunset until the end of 'Isha (the last part of the night). With its disappearance, the time for Maghrib prayer ends, and the time for 'Isha prayer begins. The Prophet, peace and blessings be upon him, said: "Twilight is the redness. When the twilight disappears, the prayer becomes due." The view of the majority of scholars, including Malik and Ahmad, is that twilight refers to the redness, while Abu Hanifa and Al-Muzani hold that it refers to the whiteness.