diff --git a/htdocs/categories/class/categorie.class.php b/htdocs/categories/class/categorie.class.php
index fb74a29a9f5..03a66adab74 100644
--- a/htdocs/categories/class/categorie.class.php
+++ b/htdocs/categories/class/categorie.class.php
@@ -1349,6 +1349,7 @@ class Categorie extends CommonObject
 
 	/**
 	 *	Return name and link of category (with picto)
+	 *  Use ->id, ->ref, ->label, ->color
 	 *
 	 *	@param		int		$withpicto		0=No picto, 1=Include picto into link, 2=Only picto
 	 *	@param		string	$option			Sur quoi pointe le lien ('', 'xyz')
@@ -1363,13 +1364,18 @@ class Categorie extends CommonObject
 		$label=$langs->trans("ShowCategory").': '. ($this->ref?$this->ref:$this->label);
 
 		// Check contrast with background and correct text color
-		$color = colorArrayToHex(colorStringToArray($this->color,array()),'');
-		$forced_color='000';
-		$tmpcolorweight=0;
-		foreach(colorStringToArray($color,array()) as $x) $tmpcolorweight+=$x;
-		if ($tmpcolorweight < 400) $forced_color='FFF';
+		$forced_color='categtextwhite';
+		if ($this->color)
+		{
+    		$hex=$this->color;
+    		$r = hexdec($hex[0].$hex[1]);
+    		$g = hexdec($hex[2].$hex[3]);
+    		$b = hexdec($hex[4].$hex[5]);
+    		$bright = (max($r, $g, $b) + min($r, $g, $b)) / 510.0;    // HSL algorithm
+    		if ($bright > 0.6) $forced_color='categtextblack';        // Higher than 60%
+		}		
 
-        $link = '<a href="'.DOL_URL_ROOT.'/categories/viewcat.php?id='.$this->id.'&type='.$this->type.'" title="'.dol_escape_htmltag($label, 1).'" class="classfortooltip"' . ( $forced_color ? ' style="color: #'.$forced_color.'"' : '' ) .'>';
+        $link = '<a href="'.DOL_URL_ROOT.'/categories/viewcat.php?id='.$this->id.'&type='.$this->type.'" title="'.dol_escape_htmltag($label, 1).'" class="classfortooltip '.$forced_color .'">';
 		$linkend='</a>';
 
 		$picto='category';
diff --git a/htdocs/core/class/html.formother.class.php b/htdocs/core/class/html.formother.class.php
index 1727db5f227..078dc01d96f 100644
--- a/htdocs/core/class/html.formother.class.php
+++ b/htdocs/core/class/html.formother.class.php
@@ -595,13 +595,20 @@ class FormOther
      */
     static function showColor($color, $textifnotdefined='')
     {
+    	$textcolor='FFF';
+    	if ($color)
+    	{
+        	$hex=$color;
+        	$r = hexdec($hex[0].$hex[1]);
+        	$g = hexdec($hex[2].$hex[3]);
+        	$b = hexdec($hex[4].$hex[5]);
+        	$bright = (max($r, $g, $b) + min($r, $g, $b)) / 510.0;    // HSL algorithm
+            if ($bright > 0.6) $textcolor='000';     	   
+    	}
+    	
     	include_once DOL_DOCUMENT_ROOT.'/core/lib/functions2.lib.php';
-
     	$color = colorArrayToHex(colorStringToArray($color,array()),'');
-    	$textcolor='000';
-    	$tmpcolorweight=0;
-    	foreach(colorStringToArray($color,array()) as $x) $tmpcolorweight+=$x;
-    	if ($tmpcolorweight < 400) $textcolor='FFF';
+    	
 		if ($color) print '<input type="text" class="colorthumb" disabled style="padding: 1px; margin-top: 0; margin-bottom: 0; color: #'.$textcolor.'; background-color: #'.$color.'" value="'.$color.'">';
 		else print $textifnotdefined;
     }
diff --git a/htdocs/theme/eldy/style.css.php b/htdocs/theme/eldy/style.css.php
index a756e1f941c..1aa5b41ac3f 100644
--- a/htdocs/theme/eldy/style.css.php
+++ b/htdocs/theme/eldy/style.css.php
@@ -3655,22 +3655,31 @@ a span.select2-chosen
   overflow: hidden;
 }
 
+
+/* ============================================================================== */
+/*  For categories                                                                */
+/* ============================================================================== */
+
 .noborderoncategories {
 	border: none !important;
 	border-radius: 5px !important;
 	box-shadow: none;
 	-webkit-box-shadow: none !important;
     box-shadow: none !important;
-    color: #fff;
 }
 span.noborderoncategories a, li.noborderoncategories a {
-	color: #fff;
 	line-height: normal;
 	vertical-align: top;
 }
 span.noborderoncategories {
 	padding: 3px 5px 0px 5px;
 }
+.categtextwhite, .treeview .categtextwhite.hover {
+	color: #fff !important;
+}
+.categtextblack {
+	color: #000 !important;
+}
 
 
 /* ============================================================================== */
diff --git a/htdocs/theme/md/style.css.php b/htdocs/theme/md/style.css.php
index fe1e161dfc8..e08512b9ca4 100644
--- a/htdocs/theme/md/style.css.php
+++ b/htdocs/theme/md/style.css.php
@@ -2789,6 +2789,14 @@ table.dp {
 	color: rgb(<?php print $colortextlink; ?>);
 }
 
+.categtextwhite, .treeview .categtextwhite.hover {
+	color: #fff !important;
+}
+.categtextblack {
+	color: #000 !important;
+}
+
+
 /* ============================================================================== */
 /*  Afficher/cacher                                                               */
 /* ============================================================================== */
@@ -3498,22 +3506,30 @@ a span.select2-chosen
   overflow: hidden;
 }
 
+
+/* ============================================================================== */
+/*  For categories                                                                */
+/* ============================================================================== */
+
 .noborderoncategories {
 	border: none !important;
 	border-radius: 5px !important;
 	box-shadow: none;
 	-webkit-box-shadow: none !important;
     box-shadow: none !important;
-    color: #fff !important;
 }
 span.noborderoncategories a, li.noborderoncategories a {
-	color: #fff !important;
 	line-height: normal;
 }
 span.noborderoncategories {
 	padding: 5px 5px 0px 5px;
 }
-
+.categtextwhite, .treeview .categtextwhite.hover {
+	color: #fff !important;
+}
+.categtextblack {
+	color: #000 !important;
+}
 
 
 /* ============================================================================== */