diff --git a/htdocs/core/modules/mrp/doc/pdf_vinci.modules.php b/htdocs/core/modules/mrp/doc/pdf_vinci.modules.php
index 20fd7b0472b..9c6987bddbb 100644
--- a/htdocs/core/modules/mrp/doc/pdf_vinci.modules.php
+++ b/htdocs/core/modules/mrp/doc/pdf_vinci.modules.php
@@ -286,7 +286,7 @@ class pdf_vinci extends ModelePDFMo
 				$pdf->SetCreator("Dolibarr ".DOL_VERSION);
 				$pdf->SetAuthor($outputlangs->convToOutputCharset($user->getFullName($outputlangs)));
 				$pdf->SetKeyWords($outputlangs->convToOutputCharset($object->ref)." ".$outputlangs->transnoentities("Mo")." ".$outputlangs->convToOutputCharset($object->thirdparty->name));
-				if (!empty($conf->global->MAIN_DISABLE_PDF_COMPRESSION)) {
+				if (getDolGlobalString('MAIN_DISABLE_PDF_COMPRESSION')) {
 					$pdf->SetCompression(false);
 				}
 
diff --git a/htdocs/core/modules/printsheet/doc/pdf_standardlabel.class.php b/htdocs/core/modules/printsheet/doc/pdf_standardlabel.class.php
index c1b93be6653..0e9eefa1e45 100644
--- a/htdocs/core/modules/printsheet/doc/pdf_standardlabel.class.php
+++ b/htdocs/core/modules/printsheet/doc/pdf_standardlabel.class.php
@@ -294,7 +294,7 @@ class pdf_standardlabel extends CommonStickerGenerator
 		$pdf->SetCreator("Dolibarr ".DOL_VERSION);
 		$pdf->SetAuthor($outputlangs->convToOutputCharset($user->getFullName($outputlangs)));
 		$pdf->SetKeyWords($keywords);
-		if (!empty($conf->global->MAIN_DISABLE_PDF_COMPRESSION)) {
+		if (getDolGlobalString('MAIN_DISABLE_PDF_COMPRESSION')) {
 			$pdf->SetCompression(false);
 		}
 
diff --git a/htdocs/core/modules/printsheet/doc/pdf_tcpdflabel.class.php b/htdocs/core/modules/printsheet/doc/pdf_tcpdflabel.class.php
index 907b18daef3..0d380ce1537 100644
--- a/htdocs/core/modules/printsheet/doc/pdf_tcpdflabel.class.php
+++ b/htdocs/core/modules/printsheet/doc/pdf_tcpdflabel.class.php
@@ -317,7 +317,7 @@ class pdf_tcpdflabel extends CommonStickerGenerator
 		$pdf->SetCreator("Dolibarr ".DOL_VERSION);
 		$pdf->SetAuthor($outputlangs->convToOutputCharset($user->getFullName($outputlangs)));
 		$pdf->SetKeyWords($keywords);
-		if (!empty($conf->global->MAIN_DISABLE_PDF_COMPRESSION)) {
+		if (getDolGlobalString('MAIN_DISABLE_PDF_COMPRESSION')) {
 			$pdf->SetCompression(false);
 		}