Die vorliegende Anmeldung betrifft ein Verfahren zur Aufhell- und Blondierung keratinischer Fasern, welches durch eine zweistufige Anwendung von oxidativer Blondierzubereitung und reduktiver Nachbehandlung gekennzeichnet ist. Weiterhin wird eine Verpackungseinheit, umfassend solche Blondierzubereitungen und Nachbehandlungsmittel, offenbart.Multi-component packaging unit, comprises: (i) at least one container containing an oxidizing agent preparation, which contains at least hydrogen peroxide in a carrier and/or its additional products with organic or inorganic carrier (ii) at least one container containing at least one bleaching activator preparation, which contains at least one persalt and (iii) and at least one container containing at least one post-treating agent, which contains at least one reducing agent in the carrier, and the containers are separately assembled. An independent claim is also included for lightening keratin fibers, comprising (a) applying a lightening- and/or bleaching preparation to the fibers, allowing to stand for an exposure time on the fibers and washing with water, and (b) applying post-treating agent to the keratin fibers, allowing to stand for exposure time on the fibers and washing, where the lightening- and/or bleaching preparation is prepared immediately before use by mixing the oxidizing agent preparation and bleaching activator preparation and optionally alkalizing preparation and the period between the completion of the first step and the beginning of the second step is more than 60 minutes.