diff --git a/contrib/ext_editor.lua b/contrib/ext_editor.lua
new file mode 100644
index 0000000..9a9c834
--- /dev/null
+++ b/contrib/ext_editor.lua
@@ -0,0 +1,422 @@
+--[[
+
+	DESCRIPTION
+    ext_editor.lua - edit images with external editors
+
+    This script provides helpers to edit image files with programs external to darktable.
+	It adds:
+		-	a new target storage "collection". Image exported will be reimported to collection for
+			further edit with external programs
+		-	a new lighttable module "external editors", to select a program from a list of up to
+		-	9 external editors and run it on a selected image
+		-	a set of lua preferences in order to configure name and path of up to 9 external editors
+		-	a set of lua shortcuts in order to quick launch the external editors
+		
+	USAGE
+    * require this script from main lua file
+	
+	-- setup --
+	* in "preferences/lua options" configure name and path/command of external programs
+	* note that if a program name is left empty, that and all following entries will be ignored
+	* in "preferences/shortcuts/lua" configure shortcuts for external programs (optional)
+	* whenever programs preferences are changed, in lighttable/external editors, press "update list"
+
+	-- use --
+    * in the export dialog choose "collection" and select the format and bit depth for the
+      exported image
+    * press "export"
+	* the exported image will be imported into collection and grouped with the original image
+    
+	* select an image for editing with en external program, and:
+		* in lighttable/external editors, select program and press "edit"
+		* edit the image with the external editor, overwite the file, quit the external program
+		* the selected image will be updated
+		or
+		* in lighttable/external editors, select program and press "edit a copy"
+		* edit the image with the external editor, overwite the file, quit the external program
+		* a copy of the selected image will be created and updated
+		or
+		* in lighttable select target storage "collection"
+		* enter in darkroom
+		* to create an export or a copy press CRTL+E
+		* use the shortcut to edit the current image with the corresponding external editor
+		* overwite the file, quit the external program
+		* the darkroom view will be updated
+	
+	* warning: mouseover on lighttable/filmstrip will prevail on current image
+	* this is the default DT behavior, not a bug of this script
+
+    CAVEATS
+	* MAC compatibility not tested
+	
+	TODO
+	* send multiple images to the same program, maybe
+	
+    BUGS, COMMENTS, SUGGESTIONS
+    * send to Marco Carrarini, marco.carrarini@gmail.com
+
+    CHANGES
+    * 20191224 - initial version
+	* 20191227 - added button "update list", better error handling, fixed bug with groups/tags in "edit"
+	
+]]
+
+
+local dt = require "darktable"
+local du = require "lib/dtutils"
+local df = require "lib/dtutils.file"
+local dtsys = require "lib/dtutils.system"
+
+
+-- module name
+local MODULE_NAME = "ext_editor"
+
+
+-- check API version
+du.check_min_api_version("5.0.2", MODULE_NAME)  -- darktable 3.0
+
+
+-- OS compatibility
+local PS = dt.configuration.running_os == "windows" and  "\\"  or  "/"
+
+
+-- translation
+local gettext = dt.gettext
+gettext.bindtextdomain(MODULE_NAME, dt.configuration.config_dir..PS.."lua"..PS.."locale"..PS)
+
+local function _(msgid)
+  return gettext.dgettext(MODULE_NAME, msgid)
+end
+
+
+-- number of valid entries in the list of external programs
+local n_entries = 0
+
+
+-- last used editor initialization
+if not dt.preferences.read(MODULE_NAME,"initialized", "bool") then
+	dt.preferences.write(MODULE_NAME,"lastchoice", "integer", 1)
+	dt.preferences.write(MODULE_NAME,"initialized", "bool", true)
+	end 
+local lastchoice = 1
+
+
+-- update lists of program names and paths, as well as combobox ---------------
+local function UpdateProgramList(combobox, button_pressed) 
+
+	-- initialize lists
+	program_names = {}
+	program_paths = {}
+
+	-- build lists from preferences
+	local name
+	local last = false
+	for i = 1, 9 do
+		name = dt.preferences.read(MODULE_NAME,"program_name_"..i, "string")
+		if (name == "" or name == nil) then last = true end
+		if last then 
+			if combobox[n_entries + 1] then combobox[n_entries + 1] = nil end -- remove extra combobox entries
+		else 
+			combobox[i] = i..": "..name
+			program_names[i] = name
+			program_paths[i] = df.sanitize_filename(dt.preferences.read(MODULE_NAME, "program_path_"..i, "string"))
+			n_entries = i
+			end
+		end 
+		lastchoice = dt.preferences.read(MODULE_NAME, "lastchoice", "integer")
+		if lastchoice > n_entries then 
+			lastchoice = 1 
+			dt.preferences.write(MODULE_NAME, "lastchoice", "integer", lastchoice)
+			end
+		combobox.value = lastchoice
+		if button_pressed then dt.print(_("list updated")) end
+	end
+
+
+-- shows export progress ------------------------------------------------------
+local function show_status(storage, image, format, filename, number, total, high_quality, extra_data) 
+	
+	dt.print(_("exporting image ").. number.." / "..total.." ...")
+	end
+
+
+-- callback for buttons "edit" and "edit a copy" ------------------------------
+local function OpenWith(images, choice, copy) 
+		
+	-- check choice is valid, return if not
+	if choice > n_entries then
+		dt.print(_("not a valid choice"))
+		return
+		end
+
+	-- check if one image is selected, return if not
+	if #images ~= 1 then
+		dt.print(_("please select one image"))
+		return
+		end
+	
+	local bin = program_paths[choice]
+	local friendly_name = program_names[choice]
+
+	-- check if external program executable exists, return if not
+	if not df.check_if_bin_exists(bin) then
+		dt.print(friendly_name.._(" not found"))
+		return
+		end
+
+	-- image to be edited
+	local image
+	i, image = next(images)
+	local name = image.path..PS..image.filename
+
+	-- check if image is raw, return if is
+	if image.is_raw then
+		dt.print(_("RAW not allowed"))
+		return
+		end
+
+	-- save image tags, rating and color
+	local tags = {}
+    for i, tag in ipairs(dt.tags.get_tags(image)) do
+		if not (string.sub(tag.name, 1, 9) == "darktable") then table.insert(tags, tag)	end
+		end 
+	local rating = image.rating
+	local red = image.red
+	local blue = image.blue
+	local green = image.green
+	local yellow = image.yellow
+	local purple = image.purple
+
+    -- new image
+    local new_name = name
+	local new_image = image
+    
+    if copy then
+
+		-- create unique filename
+		while true do -- dirty solution to workaround issue in lib function check_if_file_exists()
+			if dt.configuration.running_os == "windows" then 
+				if not df.check_if_file_exists(df.sanitize_filename(new_name)) then break end
+			else  
+				if not df.check_if_file_exists(new_name) then break end
+				end
+			new_name = df.filename_increment(new_name)
+			-- limit to 50 more exports of the original export
+			if string.match(df.get_basename(new_name), "_%d%d$") == "_50" then break end
+			end
+		    
+	    -- physical copy, check result, return if error
+	    local copy_success = df.file_copy(name, new_name)
+	    if not copy_success then
+		    dt.print(_("error copying file ")..name)
+		    return
+		    end    
+        end
+
+	-- launch the external editor, check result, return if error
+	local run_cmd = bin.." "..df.sanitize_filename(new_name) 
+	dt.print(_("launching ")..friendly_name.."...")	
+	local result = dtsys.external_command(run_cmd)
+	if result ~= 0 then
+		dt.print(_("error launching ")..friendly_name)
+		return
+		end
+
+    if copy then
+	    -- import in database and group
+	    new_image = dt.database.import(new_name)
+	    new_image:group_with(image)
+    else 
+        -- refresh the image view
+	    -- note that only image:drop_cache() is not enough to refresh view in darkroom mode
+	    -- therefore image must be deleted and reimported to force refresh
+
+        -- find the grouping status
+	    local image_leader = image.group_leader
+	    local group_members = image:get_group_members()
+	    local new_leader
+	    local index = nil
+	    local found = false
+	    
+	    -- membership status, three different cases
+	    if image_leader == image then
+		    if  #group_members > 1 then
+			    -- case 1: image is leader in a group with more members
+		    while not found do
+			    index, new_leader = next(group_members, index)
+			    if new_leader ~= image_leader then found = true end
+			    end
+			    new_leader:make_group_leader()
+			    image:delete()
+			    new_image = dt.database.import(name)
+			    new_image:group_with(new_leader)
+			    new_image:make_group_leader()
+		    else 
+			    -- case 2: image is the only member in group
+			    image:delete()
+			    new_image = dt.database.import(name)
+			    new_image:group_with()
+			    end
+	    else 
+		    -- case 3: image is in a group but is not leader
+		    image:delete()
+		    new_image = dt.database.import(name)
+		    new_image:group_with(image_leader)
+		    end
+	    -- refresh darkroom view
+	    if dt.gui.current_view() == dt.gui.views.darkroom then
+		    dt.gui.views.darkroom.display_image(new_image)
+		    end
+        end	  
+
+	-- restore image tags, rating and color, must be put after refresh darkroom view
+	for i, tag in ipairs(tags) do dt.tags.attach(tag, new_image) end
+	new_image.rating = rating
+	new_image.red = red
+	new_image.blue = blue
+	new_image.green = green
+	new_image.yellow = yellow
+	new_image.purple = purple
+
+    -- select the new image
+	local selection = {}
+	table.insert(selection, new_image)
+	dt.gui.selection (selection)
+
+	-- remember the last editor used
+	dt.preferences.write(MODULE_NAME, "lastchoice", "integer", choice)
+	end
+
+
+-- callback function for shortcuts --------------------------------------------
+local function program_shortcut(event, shortcut)
+	OpenWith(dt.gui.action_images, tonumber(string.sub(shortcut, -1)), false)
+	end
+
+
+-- export images and reimport in collection -----------------------------------
+local function export2collection(storage, image_table, extra_data) 
+
+	local new_name, new_image, result
+
+	for image, temp_name in pairs(image_table) do
+
+		-- images are first exported in temp folder then moved to collection folder
+
+		-- create unique filename
+		new_name = image.path..PS..df.get_filename(temp_name)
+		while true do -- dirty solution to workaround issue in lib function check_if_file_exists()
+			if dt.configuration.running_os == "windows" then 
+				if not df.check_if_file_exists(df.sanitize_filename(new_name)) then break end
+			else  
+				if not df.check_if_file_exists(new_name) then break end
+				end
+			new_name = df.filename_increment(new_name)
+			-- limit to 50 more exports of the original export
+			if string.match(df.get_basename(new_name), "_%d%d$") == "_50" then break end
+			end
+
+		-- move image to collection folder, check result, return if error
+		move_success = df.file_move(temp_name, new_name)
+		if not move_success then
+			dt.print(_("error moving file ")..temp_name)
+			return
+			end
+
+		-- import in database and group
+		new_image = dt.database.import(new_name)
+		new_image:group_with(image.group_leader)
+		end 
+	end
+
+
+-- register new storage -------------------------------------------------------
+-- note that placing this declaration later makes the export selected module
+-- not to remember the choice "collection" when restarting DT, don't know why
+dt.register_storage("exp2coll", _("collection"), show_status, export2collection)
+
+
+-- combobox, with variable number of entries ----------------------------------
+local combobox = dt.new_widget("combobox") {
+	label = _("choose program"), 
+	tooltip = _("select the external editor from the list"),
+	value = 1,
+	""
+	}
+UpdateProgramList(combobox, false) -- initialize list of programs and combobox
+
+
+-- button edit ----------------------------------------------------------------
+local button1 = dt.new_widget("button") {
+	label = _("edit"),
+	tooltip = _("open the selected image in external editor"),
+	clicked_callback = function()
+		OpenWith(dt.gui.action_images, combobox.selected, false)
+		end
+	}
+
+
+-- button edit a copy ---------------------------------------------------------
+local button2 = dt.new_widget("button") {
+	label = _("edit a copy"),
+	tooltip = _("create a copy of the selected image and open it in external editor"),
+	clicked_callback = function()
+		OpenWith(dt.gui.action_images, combobox.selected, true)
+		end
+	}
+
+
+-- button update list ---------------------------------------------------------
+local button3 = dt.new_widget("button") {
+	label = _("update list"),
+	tooltip = _("update list of programs if lua preferences are changed"),
+	clicked_callback = function()
+		UpdateProgramList(combobox, true)
+		end
+	}
+
+
+-- box for the buttons --------------------------------------------------------
+-- it doesn't seem there is a way to make the buttons equal in size
+local box1 = dt.new_widget("box") {
+    orientation = "horizontal",
+	button1,
+	button2,
+	button3
+	}
+
+
+-- register new module "external editors" in lighttable ------------------------
+dt.register_lib(
+	MODULE_NAME,       	 	
+	_("external editors"),  
+	true,	-- expandable
+	false,	-- resetable
+	{[dt.gui.views.lighttable] = {"DT_UI_CONTAINER_PANEL_RIGHT_CENTER", 100}},  
+	dt.new_widget("box") {
+		orientation = "vertical",
+		combobox,
+		box1
+		},
+	nil,	-- view_enter
+	nil		-- view_leave
+	)
+
+
+-- register the new preferences -----------------------------------------------
+for i = 9, 1, -1 do
+	dt.preferences.register(MODULE_NAME, "program_path_"..i, "string", _("command for external editor ")..i, _("command for external editor, including full path if needed"), "")
+	dt.preferences.register(MODULE_NAME, "program_name_"..i, "string", _("name of external editor ")..i, _("friendly name of external editor"), "")
+	end
+
+
+-- register the new shortcuts	-------------------------------------------------
+for i = 1, 9 do
+	dt.register_event("shortcut", program_shortcut, _("edit with program ")..i) 
+	end
+
+
+-- end of script --------------------------------------------------------------
+
+-- vim: shiftwidth=4 expandtab tabstop=4 cindent syntax=lua
+-- kate: hl Lua;
diff --git a/locale/it_IT/LC_MESSAGES/ext_editor.mo b/locale/it_IT/LC_MESSAGES/ext_editor.mo
new file mode 100644
index 0000000..1447df4
Binary files /dev/null and b/locale/it_IT/LC_MESSAGES/ext_editor.mo differ
diff --git a/locale/it_IT/LC_MESSAGES/ext_editor.po b/locale/it_IT/LC_MESSAGES/ext_editor.po
new file mode 100644
index 0000000..490fd33
--- /dev/null
+++ b/locale/it_IT/LC_MESSAGES/ext_editor.po
@@ -0,0 +1,119 @@
+# Italian translations for ext_editor package.
+# Copyright (C) 2019 THE ext_editor'S COPYRIGHT HOLDER
+# This file is distributed under the same license as the ext_editor package.
+# marco <marco.carrarini@gmail.com>, 2019.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: ext_editor\n"
+"Report-Msgid-Bugs-To: \n"
+"POT-Creation-Date: 2019-12-29 15:33+0100\n"
+"PO-Revision-Date: 2019-12-28 21:45+0100\n"
+"Last-Translator: marco <marco.carrarini@gmail.com>\n"
+"Language-Team: Italian\n"
+"Language: it\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=ASCII\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+#: ext_editor.lua:132
+msgid "list updated"
+msgstr "Lista aggiornata"
+
+#: ext_editor.lua:139
+msgid "exporting image "
+msgstr "Esportazione immagine "
+
+#: ext_editor.lua:148
+msgid "not a valid choice"
+msgstr "Scelta non valida"
+
+#: ext_editor.lua:154
+msgid "please select one image"
+msgstr "Selezionare un'immagine"
+
+#: ext_editor.lua:163
+msgid " not found"
+msgstr " non trovato"
+
+#: ext_editor.lua:174
+msgid "RAW not allowed"
+msgstr "RAW non consentito"
+
+#: ext_editor.lua:211
+msgid "error copying file "
+msgstr "Errore copia file "
+
+#: ext_editor.lua:218
+msgid "launching "
+msgstr "Lancio "
+
+#: ext_editor.lua:221
+msgid "error launching "
+msgstr "Errore lancio "
+
+#: ext_editor.lua:322
+msgid "error moving file "
+msgstr "Errore spostamento file "
+
+#: ext_editor.lua:336
+msgid "collection"
+msgstr "Collezione"
+
+#: ext_editor.lua:341
+msgid "choose program"
+msgstr "Scegli programma"
+
+#: ext_editor.lua:342
+msgid "select the external editor from the list"
+msgstr "Seleziona l'editor esterno dalla lista"
+
+#: ext_editor.lua:351
+msgid "edit"
+msgstr "Modifica"
+
+#: ext_editor.lua:352
+msgid "open the selected image in external editor"
+msgstr "Apre l'immagine selezionata nell'editor esterno"
+
+#: ext_editor.lua:361
+msgid "edit a copy"
+msgstr "Modifica copia"
+
+#: ext_editor.lua:362
+msgid "create a copy of the selected image and open it in external editor"
+msgstr "apre una copia dell'immagine selezionata nell'editor esterno"
+
+#: ext_editor.lua:371
+msgid "update list"
+msgstr "Aggiorna lista"
+
+#: ext_editor.lua:372
+msgid "update list of programs if lua preferences are changed"
+msgstr "Aggiorna la lista dei programmi se le preferenze di lua sono cambiate"
+
+#: ext_editor.lua:392
+msgid "external editors"
+msgstr "Editor esterni"
+
+#: ext_editor.lua:408
+msgid "command for external editor "
+msgstr "Comando per l'editor esterno "
+
+#: ext_editor.lua:408
+msgid "command for external editor, including full path if needed"
+msgstr ""
+"Comando per l'editor esterno, compreso il percorso completo se necessario"
+
+#: ext_editor.lua:409
+msgid "name of external editor "
+msgstr "Nome dell'editor esterno "
+
+#: ext_editor.lua:409
+msgid "friendly name of external editor"
+msgstr "Nome comune dell'editor esterno"
+
+#: ext_editor.lua:415
+msgid "edit with program "
+msgstr "Modifica con programma "