K-252c Fig xA Flat sample cell Top schematic view The was dissolved in d }

The pixel size of the camera does not automatically correspond to the speckle size, the latter depending on the optical set-up. In any case, the pixels must not be larger than the speckles. If the speckle size is about n times greater than the pixel size it is advisable to average over n × n pixels to create an “averaged” pixel intensity Ipixel, in our case (n = 3) of 3 × 3 pixels.