k(void)</h3>
    <p>Unpacks the RAW files of the image, calculates the black level (not for
      all formats). The results are placed in imgdata.image.</p>
    <p>Data reading is sometimes (not frequently) affected by settings made in
      imgdata.params (<a href="API-datastruct.html#libraw_output_params_t">libraw_output_params_t</a>);
      see <a href="API-notes.html">API notes</a> for details.</p>
    <p>The function returns an integer number in accordance with the <a href="API-notes.html#errors">retur