diff --git a/ocr b/ocr
index 8ee7cb9..ae1c537 100755
--- a/ocr
+++ b/ocr
@@ -121,11 +121,12 @@ class OCRWorkflow(WorkflowRunner):
         ocropusnlbin_job_number = 0
         for job in self.jobs:
             ocropusnlbin_job_number += 1
-            cmd = 'ocropus-nlbin -o "%s" "%s"/*' % (
+            cmd = 'ocropus-nlbin -Q "%i" -o "%s" "%s"/*' % (
+                max(1, int(self.nCores / length(self.jobs))),
                 os.path.join(job["output_dir"], "tmp", "ocropus-nlbin"),
                 os.path.join(job["output_dir"], "tmp", "tiff_files")
             )
-            ocropusnlbin_jobs.append(self.addTask(label="ocropusnlbin_job_-_%i" % (ocropusnlbin_job_number), command=cmd, dependencies=split_jobs, nCores=max(1, self.nCores / length(self.jobs)))
+            ocropusnlbin_jobs.append(self.addTask(label="ocropusnlbin_job_-_%i" % (ocropusnlbin_job_number), command=cmd, dependencies=split_jobs, nCores=max(1, int(self.nCores / length(self.jobs)))))
 
         ###
         # Task "tesseract_job": perform OCR on binarized images