Abstract: The electric lamp has a quartz glass lamp vessel in which a light source is accommodated. The lamp vessel is covered by an interference film which has layers of alternatingly silica and a material of relatively high refractive index. A silica containing adhesive layer is in between the lamp vessel and the film. The adhesive layer has a content of boron oxide and/or phosphorus oxide.

Abstract: The colored electric lamp has a lamp vessel (1) carrying a colored translucent interference filter (12) of alternately SiO.sub.2 layers and layers of comparatively high refractive index. In the filter, layers of high refractive index have an optical thickness smaller than 1/4.lambda..sub.0, while SiO.sub.2 layers have an optical thickness larger than 1/4.lambda..sub.0. An SiO.sub.2 layer of 500-900 nm thickness can be present on the filter. The light emitted by the lamp has a higher color saturation and the filter has a better adherence to the lamp vessel than in the case of a lamp comprising a conventional filter having an equal overall thickness of layers of high refractive index.