Background scattering of different media. Background scattering of (a), (b) NaCMC and (c), (d) F-127 compared with grease, and (e), (f) LCP compared with a 1:1 LCP and F-127 mixture. (a), (c), (e) Median background images of (a) NaCMC and (b) F-127 compared with grease and (e) F-127+LCP compared with LCP. Each image in parts (a), (c) and (e) is composed of two halves, that on the left being that of the standard medium (grease or LCP) and that on the right being that of the tested medium. (b), (d), (f) Radially integrated background images plotted against resolution. The green line represents grease [parts (b) and (d)], the orange line NaCMC [part (b)] and the blue line F-127 [part (d)]. In part (f), the purple line represents LCP and the blue line represents LCP+F-127. The following capillary diameters were used, yielding the measured stream diameters: (a), (b): capillary ID 150 µm, NaCMC diameter 220–230 µm, grease 135–145 µm; (c), (d): capillary ID 100 µm, F-127 diameter 200–230 µm, grease 80–100 µm; (e), (f): capillary ID 100 µm, LCP+F-127 diameter ∼200 µm, LCP ∼100 µm.