Guinier-type transformations derived from SNR profiles recorded for monolayers of (a) d74-DODAB, (b) d74-DODAB:cholesterol and (c) d74-DODAB : DOPE on a subphase of acmw(s) at surface pressures of 5 mN m−1 (open diamonds), 20 mN m−1 (open squares), 30 mN m−1 (open triangles) and 40 mN m−1 (open circles). Black lines show the fits to the data in the domain where, as required [21], Qz is small.