Experimental dataset, results and figures used in the publication "Accelerating ptychographic reconstructions using spectral initializations", by L. Valzania, J. Dong, and S. Gigan, Optics Letters 46(6), 1357-1360, 2021. The paper has also been made publicly available at the following arXiv link (please refer to the v2 version). The folder "Experimental_dataset" includes a mat file containing the following variables: - ptychograms: the measured diffraction patterns - double; - probe_initial: initial estimate of the probe - complex double; - shift_x / shift_y: relative shifts between the probe and the object along x / y, in units of pixels (same pixel units used for the ptychograms and the initial estimate of the probe) - double. The folder "Results_and_figures" includes the ptychographic reconstructions, both in .png and .npy formats. An example of reconstruction software has been uploaded at the following GitHub repository.