diff --git a/rtdata/languages/default b/rtdata/languages/default
index beaf99a90..89350cfe6 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -2429,6 +2429,7 @@ TP_LOCALLAB_EXPLAP_TOOLTIP;The more you act on this threshold slider, the greate
 TP_LOCALLAB_EXPLAPBAL_TOOLTIP;Balances the action between the original image and the Laplace transform.
 TP_LOCALLAB_EXPLAPLIN_TOOLTIP;Add linear exposure component before application Laplace transform
 TP_LOCALLAB_EXPLAPGAMM_TOOLTIP;Apply a gamma before and after Laplace transform
+TP_LOCALLAB_EXPMERGEFILE_TOOLTIP;Allows various possibilities to blend image (as layers in Photosshop) : difference, multiply, soft light, overlay...with opacity...  
 TP_LOCALLAB_EXPNOISEMETHOD_TOOLTIP;Apply a median before Laplace transform to prevent artifacts (noise).\nYou can also use "Denoise" tool.
 TP_LOCALLAB_EXPMETHOD_TOOLTIP;Standard : use an algorithm similar as main Exposure but in L*a*b* and taking account of deltaE.\n\nLaplacian & PDE : use another algorithm also with deltaE and with Poisson equation to solve Laplacian in Fourier space.\nPDE IPOL, PDE Fattal and Standard can be combined.\nFFTW Fourier Transform is optimized in size to reduce processing time.\nPDE reduce artifacts and noise.
 TP_LOCALLAB_EXPOSE;Exposure - Dynamic Range Compression
diff --git a/rtgui/locallabtools.cc b/rtgui/locallabtools.cc
index 4780eb00b..2f220731e 100644
--- a/rtgui/locallabtools.cc
+++ b/rtgui/locallabtools.cc
@@ -885,6 +885,7 @@ void LocallabColor::updateAdviceTooltips(const bool showTooltips)
         lapmaskcol->set_tooltip_text(M("TP_LOCALLAB_LAPRAD_TOOLTIP"));
         Lmaskshape->setTooltip(M("TP_LOCALLAB_LMASK_LL_TOOLTIP"));
         LLmaskcolshapewav->setTooltip(M("TP_LOCALLAB_LMASK_LEVEL_TOOLTIP"));
+        expmaskcol1->set_tooltip_text(M("TP_LOCALLAB_EXPMERGEFILE_TOOLTIP"));
     } else {
         lightness->set_tooltip_text("");
         sensi->set_tooltip_text("");
@@ -901,6 +902,7 @@ void LocallabColor::updateAdviceTooltips(const bool showTooltips)
         lapmaskcol->set_tooltip_text("");
         Lmaskshape->setTooltip("");
         LLmaskcolshapewav->setTooltip("");
+        expmaskcol1->set_tooltip_text(M(""));
     }
 }