LibRaw::error_count()</h4>
    <p>This call returns count of non-fatal data errors (out of range, etc)
      occurred in unpack() stage.</p>
    <p><a name="subtract_black"></a></p>
    <h4>int LibRaw::subtract_black()</h4>
    <p>This call will subtract black level values from RAW data (for suitable
      RAW data). <a href="API-datastruct.html#libraw_colordata_t">colordata.data_maximum</a>
      and <strong>colordata.maximum</strong> and black level data (<a href="API-datastruct.html#libraw_colordata_t">c