Substituted phthalocyanines

A phthalocyanine of the formula:

• ##STR19## where M is a metal atom or a metal halide or oxide, or M is 2H, one H being bonded to each of the two bonding nitrogen atoms at positions 29 and 31 as shown;
• R.sub.1 to R.sub.8 are the same or different and are independently selected from C.sub.1 -C.sub.10 alkyl, C.sub.2 -C.sub.20 alkenyl, X--O--Y, X-phenyl, X.sup.2 COOX.sup.1 and X.sup.2 CONR.sup.1 R.sup.11, where X and X.sup.2 are independently selected from a chemical bond, --(CH.sub.2).sub.n -- where n is an integer from 1 to 20, and (CH.sub.2).sub.a CH.dbd.CH(CH.sub.2).sub.b where a and b are independently selected from integers from 0 to 20 and a +b is from 0 to 20;
• X.sup.1 is independently selected from C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl and H, R.sup.1 and R.sup.11 are independently selected from H, C.sub.1 -C.sub.20 alkyl and C.sub.2 -C.sub.20 alkenyl, and Y is independently selected from the C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl, --(CH.sub.2).sub.n -phenyl where n is integer from 0 to 20 and H provided that not all of the groups R.sub.1 to R.sub.8 are simultaneously X--O--Y where X is a chemical bond and Y is alkyl.