Abstract: This invention relates to a one- or two-component diazo-type material with improved light stability and duplication capabilities. This is accomplished by using compounds of the general formula ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 being the same or different, represent hydrogen, alkyl with 1 to 5 carbon atoms, R.sub.1 and R.sub.2 and/or R.sub.3 and R.sub.4 represent the alkyl groups necessary for completion of a 5- or 6-membered heterocyclic ring, wherein the ring may comprise a further hetero atom, such as N, O or S;R.sub.5, R.sub.6 being the same or different, represent hydrogen, aryl, alkyl with 1 to 4 carbon atoms;Y represents --S--, --SO--, --SO.sub.2 --; andn is 0, 1, 2, 3,which are added to the material as fading inhibitors. These compounds can be easily synthesized and are compatible with the system, having an absorption maximum below 380 nm and reduced fogging tendency. They may also be employed in the form of their hydro salts.