The emergence of femtosecond diffractive imaging with X-ray lasers has enabled 
pioneering structural studies of isolated particles, such as viruses, at 
nanometer length scales. However, the issue of missing low frequency data 
significantly limits the potential of X-ray lasers to reveal sub-nanometer 
details of micrometer-sized samples. We have developed a new technique of 
dark-field coherent diffractive imaging to simultaneously overcome the missing 
data issue and enable us to harness the unique contrast mechanisms available in 
dark-field microscopy. Images of airborne particulate matter (soot) up to two 
microns in length were obtained using single-shot diffraction patterns obtained 
at the Linac Coherent Light Source, four times the size of objects previously 
imaged in similar experiments. This technique opens the door to femtosecond 
diffractive imaging of a wide range of micrometer-sized materials that exhibit 
irreproducible complexity down to the nanoscale, including airborne particulate 
matter, small cells, bacteria and gold-labeled biological samples.