A positive-working radiation-sensitive mixture is described which essentially contains a photoactive component and a water-insoluble binder which is soluble, or at least swellable, in aqueous alkaline solution, wherein a compound is used, as photoactive component, which contains .alpha.-diazo-.beta.-keto ester units and sulfonate units of the formula I ##STR1## in which R.sup.1 and R.sup.2, independently of one another, are an unsubstituted or substituted aliphatic, cycloaliphatic, araliphatic or aromatic radical having 4 to 20 carbon atoms, it being possible for individual CH.sub.2 groups to be replaced by oxygen or sulfur atoms or by N or NH groups and/or contain keto groups,X is an unsubstituted or substituted aliphatic, cycloaliphatic, carbocyclic, heterocyclic or araliphatic radical having 2 to 22 carbon atoms, it being possible for individual CH.sub.2 groups to be replaced by oxygen or sulfur atoms or by the groups --NR.sup.3 --, --C(O)--0--, --C(O)--NR.sup.3 --, ##STR2## --NR.sup.3 --C(O)--NR.sup.4 --, --O--C(O)--NR.sup.3 --, ##STR3## or --O--C(O)--O--, or CH groups to be replaced by ##STR4## in which R.sup.3 and R.sup.4, independently of one another, are hydrogen or an unsubstituted or substituted aliphatic, carbocyclic or araliphatic radical,m is an integer from 3 to 8,n is an integer from 1 to 3, and m>n.The radiation-sensitive mixture is especially suitable for exposure to radiation having a wavelength of about 190 to 300 nm.