sample (H in Fig. \[fig:phasediag\]) at the lowest scattering angle. Therefore we assume that the scattered intensity is from colloids only. Under these conditions, our measurements probe the structure and dynamics of the particles alone.

The static structure factor was measured with the procedure described in [@measureSq]. First, the total average intensities, $\left<I_B\right>$ and $\left<I_G\right>$, and the intercept, $\beta^2\beta_{MS}^2={g^{(2)}}(q,0)-1$, of a concentrated sample of interest were measured at different scattering vectors $q$. The sample was rotated continuously during the measurement to ensure ensemble average. Since the rotation only changes the time-dependence of ${g^{(2)}}(q,\tau)$, the intercept and average intensity were not affected. It was found that it was necessary to average measurements at different height in the sample for non-ergodic samples to reduce random noise from the finite number of speckles sampled. Then the same measurements were made on a dilute suspension of known $\phi$ to obtain the single-particle form factor. The volume fraction of this dilute sample was $\phi_{\rm dil}=0.01$, small enough that multiple scattering can be ignored, so that the measured intercept contains only the instrument related factor: $\beta^2={g^{(2)}}_{\rm dil}(q,0)-1$, which was the same as that in the measurement of the concentrated sample.

The static structure factor is the 