Abstract: The invention provides a composition comprising a hydrophilic colloid and a surface active agent characterised in that the surface active agent is a compound having the formula ##STR1## wherein each of R.sub.1, R.sub.2 and R.sub.3 independently is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group;each of X and Y is --H or --Q.sup.- M.sup.+ ;Q.sup.- is an anion; and,M.sup.+ is a cation;provided that when X is --H, Y is --Q.sup.- M.sup.+ and that when X is --Q.sup.- M.sup.+, Y is --H.Preferred surface active agents include compounds of the above formula wherein R.sub.1, R.sub.2 and R.sub.3 are identical.The anion Q.sup.- is a negatively charged atom or group of atoms preferably comprising a sulphonate group, such as --SO.sub.3.sup.- or --CH.sub.2 SO.sub.3.sup.- or a sulphate group, such as --OSO.sub.3.sup.-.The cation M.sup.+ is a positively charged atom or group of atoms preferably chosen from alkali metal cations, such as Na.sup.+ or ammonium.