diff --git a/luametalatex-back-pdf.lua b/luametalatex-back-pdf.lua
index 0d9cf25..6d7d04c 100644
--- a/luametalatex-back-pdf.lua
+++ b/luametalatex-back-pdf.lua
@@ -1,8 +1,15 @@
+local pdf = pdf
 local writer = require'luametalatex-nodewriter'
 local newpdf = require'luametalatex-pdf'
 local pfile = newpdf.open(tex.jobname .. '.pdf')
 local fontdirs = setmetatable({}, {__index=function(t, k)t[k] = pfile:getobj() return t[k] end})
 local usedglyphs = {}
+local colorstacks = {{
+    page = true,
+    mode = "direct",
+    default = "0 g 0 G",
+    page_stack = {"0 g 0 G"},
+  }}
 token.luacmd("shipout", function()
   local voff = node.new'kern'
   voff.kern = tex.voffset + pdf.variable.vorigin
@@ -11,7 +18,7 @@ token.luacmd("shipout", function()
   local list = node.vpack(voff)
   list.height = tex.pageheight
   list.width = tex.pagewidth
-  local out, resources, annots = writer(pfile, list, fontdirs, usedglyphs)
+  local out, resources, annots = writer(pfile, list, fontdirs, usedglyphs, colorstacks)
   local page, parent = pfile:newpage()
   local content = pfile:stream(nil, '', out)
   pfile:indirect(page, string.format([[<</Type/Page/Parent %i 0 R/Contents %i 0 R/MediaBox[0 %i %i %i]/Resources%s%s>>]], parent, content, -math.ceil(list.depth/65781.76), math.ceil(list.width/65781.76), math.ceil(list.height/65781.76), resources, annots))
@@ -42,5 +49,89 @@ token.luacmd("pdfvariable", function()
   end
   -- The following error message gobbles the next word as a side effect.
   -- This is intentional to make error-recovery easier.
-  error(string.format("Unknown PDF variable %s", token.scan_string()))
+  error(string.format("Unknown PDF variable %s", token.scan_word()))
+end)
+local whatsit_id = node.id'whatsit'
+local whatsits = node.whatsits()
+function pdf.newcolorstack(default, mode, page)
+  local idx = #colorstacks
+  colorstacks[idx + 1] = {
+    page = page,
+    mode = mode or "origin",
+    default = default,
+    page_stack = {default},
+  }
+  return idx
+end
+local function do_colorstack(prop, p, n, x, y)
+  local colorstack = prop.colorstack
+  local stack
+  if p.is_page then
+    stack = colorstack.page_stack
+  elseif prop.last_form == resources then
+    stack = colorstack.form_stack
+  else
+    stack = {prop.default}
+    colorstack.form_stack = stack
+  end
+  if prop.action == "push" then
+    stack[#stack+1] = prop.data
+  elseif prop.action == "pop" then
+    assert(#stack > 1)
+    stack[#stack] = nil
+  elseif prop.action == "set" then
+    stack[#stack] = prop.data
+  end
+  pdf.write(colorstack.mode, stack[#stack], x, y, p)
+end
+local function write_colorstack()
+  local idx = token.scan_int()
+  local colorstack = colorstacks[idx + 1]
+  if not colorstack then
+    error[[Undefined colorstack]]
+  end
+  local action = token.scan_keyword'pop' and 'pop'
+              or token.scan_keyword'set' and 'set'
+              or token.scan_keyword'current' and 'current'
+              or token.scan_keyword'push' and 'push'
+  if not action then
+    error[[Missing action specifier for colorstack command]]
+  end
+  local text
+  if action == "push" or "set" then
+    text = token.scan_string()
+    -- text = token.to_string(token.scan_tokenlist()) -- Attention! This should never be executed in an expand-only context
+  end
+  local whatsit = node.new(whatsit_id, whatsits.pdf_colorstack)
+  node.setproperty(whatsit, {
+      handle = do_colorstack,
+      colorstack = colorstack,
+      action = action,
+      data = text,
+    })
+  node.write(whatsit)
+end
+token.luacmd("pdffeedback", function()
+  if token.scan_keyword"colorstackinit" then
+    local page = token.scan_keyword'page'
+              or (token.scan_keyword'nopage' and false) -- If you want to pass "page" as mode
+    local mode = token.scan_keyword'direct' and 'direct'
+              or token.scan_keyword'page' and 'page'
+              or 'origin'
+    local default = token.scan_string()
+    tex.sprint(tostring(pdf.newcolorstack(default, mode, page)))
+  else
+  -- The following error message gobbles the next word as a side effect.
+  -- This is intentional to make error-recovery easier.
+    error(string.format("Unknown PDF feedback %s", token.scan_word()))
+  end
+end)
+token.luacmd("pdfextension", function()
+  if token.scan_keyword"colorstack" then
+    write_colorstack()
+  else
+  -- The following error message gobbles the next word as a side effect.
+  -- This is intentional to make error-recovery easier.
+    error(string.format("Unknown PDF extension %s", token.scan_word()))
+  end
 end)
diff --git a/luametalatex-init.lua b/luametalatex-init.lua
index afc8445..5d8e847 100644
--- a/luametalatex-init.lua
+++ b/luametalatex-init.lua
@@ -314,7 +314,13 @@ end
 --
 -- unicode = {utf8 = utf8}
 -- utf8.byte = utf8.codepoint
-kpse.set_program_name()
+do
+  local progname
+  for _, a in ipairs(arg) do if a:sub(1,11) == "--progname=" then
+    progname = a:sub(12)
+  end end
+  kpse.set_program_name(nil, progname)
+end
 package.searchers[2] = function(modname)
   local filename = kpse.find_file(modname, "kpse_lua_format", true)
   if not filename then
diff --git a/luametalatex-nodewriter.lua b/luametalatex-nodewriter.lua
index 562c010..8cb11ee 100644
--- a/luametalatex-nodewriter.lua
+++ b/luametalatex-nodewriter.lua
@@ -26,7 +26,7 @@ end)()
 local whatsithandler = (function()
   local whatsits = node.whatsits()
   local function unknown_handler(p, n, x, y, ...)
-    local prop = properties[n]
+    local prop = properties[n] or node.getproperty(n)
     if prop and prop.handle then
       prop:handle(p, n, x, y, ...)
     else
@@ -398,7 +398,8 @@ function nodehandler.glyph(p, n, x, y, ...)
   local f, fid = p.vfont.font, p.vfont.fid
   local c = f.characters[n.char]
   if not c then
-    error[[Invalid characters]]
+    texio.write_nl("Missing character")
+    return
   end
   if c.commands then return do_commands(p, c, f, fid, x, y, ...) end
   toglyph(p, n.font, x + n.xoffset, y + n.yoffset, n.expansion_factor)
@@ -473,6 +474,25 @@ function whatsithandler.pdf_end_link(p, n, x, y, outer, _, level)
   if link.level ~= level then error[[Wrong link level]] end
   addlinkpoint(p, link, x, y, outer, true)
 end
+local global_p, global_x, global_y
+function pdf._latelua(p, x, y, func, ...)
+  global_p, global_x, global_y = p, x, y
+  return func(...)
+end
+function pdf.write(mode, text, x, y, p)
+  x, y, p = x or global_x, y or global_y, p or global_p
+  if mode == "direct" then
+    topage(p)
+    p.strings[#p.strings + 1] = text
+  elseif mode == "origin" then
+    write_matrix(p, 1, 0, 0, 1, x, y)
+    topage(p)
+    p.strings[#p.strings + 1] = text
+    write_matrix(p, 1, 0, 0, 1, -x, -y)
+  else
+    write(format('Literal type %s unsupported', mode))
+  end
+end
 local ondemandmeta = {
   __index = function(t, k)
     t[k] = {}
@@ -494,7 +514,7 @@ local function writeresources(p)
   return concat(result)
 end
 local fontnames = setmetatable({}, {__index = function(t, k) local res = format("F%i", k) t[k] = res return res end})
-return function(file, n, fontdirs, usedglyphs)
+return function(file, n, fontdirs, usedglyphs, colorstacks)
   setmetatable(usedglyphs, ondemandmeta)
   local linkcontext = file.linkcontext
   if not linkcontext then
@@ -502,6 +522,7 @@ return function(file, n, fontdirs, usedglyphs)
     file.linkcontext = linkcontext
   end
   local p = {
+    is_page = not not colorstacks,
     file = file,
     mode = 3,
     strings = {},
@@ -521,6 +542,17 @@ return function(file, n, fontdirs, usedglyphs)
     annots = {},
     linkcontext = file.linkcontext,
   }
+  if colorstacks then
+    for i=1, #colorstacks do
+      local colorstack = colorstacks[i]
+      if colorstack.page then
+        local stack = colorstack.page_stack
+        if colorstack.default ~= stack[#stack] then
+          pdf.write(colorstack.mode, stack[#stack], 0, 0, p)
+        end
+      end
+    end
+  end
   nodehandler[n.id](p, n, 0, 0, n, nil, 0)
   -- nodehandler[n.id](p, n, 0, n.depth, n)
   topage(p)