Abstract: A white blackout fiber comprising a unitary fiber having a light blocking substance that substantially prevents the transmission of light therethrough and a whitening agent, where the whitening agent is present in an amount which provides for good after processing while the light blocking substance is present in the maximum amount which is masked by the whitening agent. Generally, the whitening agent is present in an amount between about 2.5-4% by weight of the fiber, and the whitening agent and light blocking substance are present in a ratio of between about 1000:1 and 800:1. Preferably, the whitening agent is TiO.sub.2 and the light blocking substance is carbon black.

Abstract: A white blackout fiber comprising a core, a sheath, said sheath surrounding said core, said core including a light blocking substance therein that substantially prevents the transmission of light therethrough, the light blocking substance being in an amount equal to 0.005-0.01 weight % of the core, a whitening agent in the core in an amount equal to 3-10% of the weight of the core, and a whitening agent in the sheath in an amount equal to approximately 0.0-4.0 weight % of the sheath.