diff --git a/src/app/modules/colors/pages/add/add.component.ts b/src/app/modules/colors/pages/add/add.component.ts
index 6eef38b..c8569c0 100644
--- a/src/app/modules/colors/pages/add/add.component.ts
+++ b/src/app/modules/colors/pages/add/add.component.ts
@@ -6,7 +6,7 @@ import {Validators} from '@angular/forms'
 import {CompanyService} from '../../../company/service/company.service'
 import {map} from 'rxjs/operators'
 import {ActivatedRoute, Router} from '@angular/router'
-import {ErrorModel, ErrorService} from '../../../shared/service/error.service'
+import {ErrorService} from '../../../shared/service/error.service'
 
 @Component({
   selector: 'cre-add',
@@ -40,7 +40,7 @@ export class AddComponent extends ErrorHandlingComponent {
       label: 'Échantillon',
       icon: 'pound',
       type: 'number',
-      validator: Validators.compose([Validators.required, Validators.min(0)]),
+      validator: Validators.min(0),
       errorMessages: [
         {conditionFn: errors => errors.required, message: 'Un numéro d\'échantillon est requis'},
         {conditionFn: errors => errors.min, message: 'Le numéro d\'échantillon doit être supérieur ou égal à 0'}
diff --git a/src/app/modules/colors/pages/edit/edit.component.ts b/src/app/modules/colors/pages/edit/edit.component.ts
index bbea551..2cc6289 100644
--- a/src/app/modules/colors/pages/edit/edit.component.ts
+++ b/src/app/modules/colors/pages/edit/edit.component.ts
@@ -50,7 +50,7 @@ export class EditComponent extends ErrorHandlingComponent {
       label: 'Échantillon',
       icon: 'pound',
       type: 'number',
-      validator: Validators.compose([Validators.required, Validators.min(0)]),
+      validator: Validators.min(0),
       errorMessages: [
         {conditionFn: errors => errors.required, message: 'Un numéro d\'échantillon est requis'},
         {conditionFn: errors => errors.min, message: 'Le numéro d\'échantillon doit être supérieur ou égal à 0'}
diff --git a/src/app/modules/colors/pages/list/list.component.html b/src/app/modules/colors/pages/list/list.component.html
index c6a02ab..3b24baf 100644
--- a/src/app/modules/colors/pages/list/list.component.html
+++ b/src/app/modules/colors/pages/list/list.component.html
@@ -39,7 +39,9 @@
 
     <ng-container matColumnDef="sample">
       <th mat-header-cell *matHeaderCellDef>Échantillon</th>
-      <td mat-cell *matCellDef="let recipe">#{{recipe.sample}}</td>
+      <td mat-cell *matCellDef="let recipe">
+        <ng-container *ngIf="recipe.sample">#{{recipe.sample}}</ng-container>
+      </td>
     </ng-container>
 
     <!-- Icons -->