TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: (A) is an organosiloxane compound of formula (R1aR3aSiO(R2SiO)m(R1RSiO)nSiR1aR3a). (B) is an organohydrogensiloxane compound of formula (Ha(R)3aSi(RHSiO)x(R2SiO)y(RR1SiO)zSi(R)3-aHa). (C) is at least one transition metal compound, which is nickel, ruthenium, rhodium, palladium, osmium, iridium or platinum. (C) is at least one light-activatable catalyst.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (D) is at least one of: (D1) at least one organosiloxane, comprising at least one alkoxy silyl group; (D2) at least one organosilane, comprising at least one alkoxy silyl group; (D3) at least one aromatic organic compound having at least two aromatic moieties and at least one group reactive in hydrosilylation. (D1) is an organosiloxane comprising at least one unit of formula (RHSiO2/2) and (R5(R)SiO2/2), and further comprising at least one unit of formula (O2/2(R)Si-R4-SiRd(OR3)3-d) (iii). (D2) is of formula (X-(CR62)e-Y1-(CH2)eSiRd(OR3)3-d). (D3) is organosilane compound of formula (d3). (E) is silica having a Brunauer, Emmett, Teller method surface of at least 150 m2/g. (I) comprises: 100 parts by weight of (A); 0.1-200 parts per weight of (B); 0.5-1000 ppm of (C); 0.01-5 parts by weight of component (D); and 0-50 parts by weight of (E).R = up to 30C alkyl, up to 30C aryl (both optionally substituted), poly(2-4C)-alkylene ether with up to 1000 alkylene oxy units, or free of aliphatic unsaturation;R1 = up to 30C aliphatic or aromatic comprising C=C-group-containing groups (alkenyl groups) or C=C-group-containing groups (alkinyl groups), optionally comprising O- or F-;a = 0-3;m = 0-2000;n = 0-500;x+y+z = 7-1000;R5 = up to 14C unsaturated aliphatic, up to 14C epoxy-group-containing aliphatic group, cyanurate-containing group, or an isocyanurate-containing group;R3 = H or 1-6C alkyl;R4 = difunctional optionally substituted up to 15C hydrocarbyl, which may contain heteroatoms of O, N or S, and which is bond to the silicon atoms via an Si-C-bond;d = 0-2;X = halo, pseudohalogen, up to 14C unsaturated aliphatic, epoxy-group-containing up to 14C aliphatic group, cyanurate-containing group, or an isocyanurate-containing group;Y1 = single bond, heteroatomic group of -O-, -S-, -CONH- or -HN-CO-NH-;R6 = H;e = 0-8;r = 0 or 1;R7 = H, OH, halo, alkyl, alkenyl, alkoxy, alkenyloxy, alkenylcarbonyloxy or aryl, or group of formulae (-Ef-Si(OR)3-dRd), (-O-Si(R)2R1) or (-Ef-Si(R)2H);E1 = up to 8C divalent organic group and 0-3 hetero atomic groups of -O-, -NH-, C=O, or -C(=O)O-;f = 0 or 1;Z = -C(-R8)2-, -S(=O)2-, -S(=O)-, -C(=O)-, -O-Si(-R8)2-O-, -(CH2)g- or -O-;R8 = H, halo, or optionally substituted alkyl, aryl, alkenyl or alkynyl; andg = at least 2.Provided that at least one of the groups of R7 and R8 is reactive in hydrosilylation. EXAMPLE - Vinyl-terminated polydimethylsiloxane polymer (52 g) having a viscosity of 10 Pa.s at 25 degrees C as component (A) was mixed with Aerosil 300 (RTM: Hexamethyldisilazane) (29 g). Then to the resulting mixture further the vinyl-terminated polydimethyl-siloxane (16.7 g) having a viscosity of 10 Pa.s was added. Then Dynasilan GLYMO (RTM: Glycidoxypropyltrimethoxysilane) (0.9 g), Dynasilan MEMO (RTM: Methacryloxypropyltrimethoxysilane) (0.25 g), an adhesion promoter (1 g), a trimethylsilyl-terminated poly(co-diphenyl-methylhydrogendimethylsiloxane) (0.9 g) were added. In a sealed darkened glove box, the light activatable metal catalyst which was trimethyl(methylcyclopentadienyl)-platinum(IV) dissolved in a vinylterminated polydimethylsiloxane of 1 Pa.s at 25 degrees C was mixed under red or yellow light of a bulb lamp (excluding at least blue and UV-light), and worked up to give the composition.