Use of iron oxide and/or cerium oxide as a decolouring agent for adjusting the light transmittance of a lithium aluminosilicate glass ceramic article, in particular of a lithium aluminosilicate glass ceramic panel, in the visible spectral range, comprising the steps of: - providing a batch for the lithium aluminosilicate glass ceramic, said batch including a colour-imparting agent, in particular a colour-imparting oxide which absorbs light in the glass ceramic in the visible spectral range between 450 and 750 nanometres, and wherein a batch is provided with at least 0.005 percent by weight of vanadium oxide as the colour-imparting agent; - melting the batch and producing a glass precursor; and - ceramizing the glass precursor to obtain a glass ceramic article; - wherein prior to or during the melting, a decolouring agent is added to the batch, which decolouring agent reduces the absorptivity of the colouring agent in at least a sub-region of the visible spectral range upon ceramization, so that, in total, the transmittance of the glass ceramic article at least remains the same and preferably increases in the visible spectral range between 450 and 750 nanometres, wherein the proportion of the decolouring agent in the glass ceramic composition is determined on the basis of a predefined light transmittance of greater than 2.5 % of the glass ceramic article in the visible spectral range when illuminated perpendicular to the surface of the glass ceramic article, and an amount of the decolouring agent corresponding to this proportion is added to the batch; wherein at least 0.1 percent by weight of iron oxide and/or at least 0.1 percent by weight of cerium oxide is added as the decolouring agent; wherein the iron oxide content is at least the same or greater than the vanadium oxide content; wherein the contents of tin oxide, titanium oxide, iron oxide, and cerium oxide in the composition of the glass ceramic meet the relationship (M(SnO 2) + 0.1 M(TiO 2)) / (M(Fe 2 O 3) + M(CeO 2)) < 4, preferably < 3, wherein M is the respective proportion, in percent by weight, of the component in the following brackets, and wherein the cerium oxide content is at most 0.6 percent by weight. - providing a batch for the lithium aluminosilicate glass ceramic, said batch including a colour-imparting agent, in particular a colour-imparting oxide which absorbs light in the glass ceramic in the visible spectral range between 450 and 750 nanometres, and wherein a batch is provided with at least 0.005 percent by weight of vanadium oxide as the colour-imparting agent; - melting the batch and producing a glass precursor; and - ceramizing the glass precursor to obtain a glass ceramic article; - wherein prior to or during the melting, a decolouring agent is added to the batch, which decolouring agent reduces the absorptivity of the colouring agent in at least a sub-region of the visible spectral range upon ceramization, so that, in total, the transmittance of the glass ceramic article at least remains the same and preferably increases in the visible spectral range between 450 and 750 nanometres, wherein the proportion of the decolouring agent in the glass ceramic composition is determined on the basis of a predefined light transmittance of greater than 2.5 % of the glass ceramic article in the visible spectral range when illuminated perpendicular to the surface of the glass ceramic article, and an amount of the decolouring agent corresponding to this proportion is added to the batch;