  Many optical microscopy techniques rely on structured illumination by way of
a projected image (eg. structured illumination microscopy) or a tailored
angular distribution of light (eg. ptychography). Electro-optical equipment
such as spatial light modulators and light emitting diode (LED) arrays are
commonly used to sculpt light for these imaging schemes. However, these
high-tech devices are not a requirement for light crafting. Patterned diffusely
reflecting surfaces also imprint a spatio-angular structure onto reflected
light. We demonstrate that paper patterned with a standard commercial printer
can serve to structure the illumination light field for refocusing and stereo
microscopy on a mobile phone microscope. Our results illustrate the utility of
paper as a light sculpting element for low-tech computational imaging.
