code: function (pdf_file, cb) {
              var quality = 300;
              if (options.hasOwnProperty('quality') && options.quality) {
                quality = options.quality;
              }
              convert(pdf_file.file_path, quality, function (err, tif_path) {
                var zeroBasedNumPages = num_pages-1;
                self.emit('log', 'converted page to intermediate tiff file, page '+ index+ ' (0-based indexing) of '+ zeroBasedNumPages);
                if (err) { return cb(err); }
                var ocr_flags = [
                  '-psm 6'
                ];
                if (options.ocr_flags) {
                  ocr_flags = options.ocr_flags;
                }
                ocr(tif_path, ocr_flags, function (err, extract) {
                  fs.unlink(tif_path, function (tif_cleanup_err, reply) {
                    if (tif_cleanup_err) {
                      err += ', error removing temporary tif file: "'+tif_cleanup_err+'"';
                    }
                    if (err) { return cb(err); }
                    var page_number = index+1
                    self.emit('log', 'raw ocr: page ' + index + ' (0-based indexing) of ' +zeroBasedNumPages + ' complete');
                    single_page_pdf_file_paths.push(pdf_file.file_path);
                    self.emit('page', { hash: hash, text: extract, index: index, num_pages: num_pages, pdf_path: pdf_path, single_page_pdf_path: pdf_file.file_path});
                    text_pages.push(extract);
                    index++;
                    cb();
                  });
                });
              });
            }
docs: extract the text for each page via ocr