diff --git a/src/calibre/ebooks/conversion/plumber.py b/src/calibre/ebooks/conversion/plumber.py
index 07299aff4e..55a46da8fe 100644
--- a/src/calibre/ebooks/conversion/plumber.py
+++ b/src/calibre/ebooks/conversion/plumber.py
@@ -8,7 +8,8 @@ import os, re, sys, shutil, pprint
 from calibre.customize.conversion import OptionRecommendation, DummyReporter
 from calibre.customize.ui import input_profiles, output_profiles, \
         plugin_for_input_format, plugin_for_output_format, \
-        available_input_formats, available_output_formats
+        available_input_formats, available_output_formats, \
+        run_plugins_on_preprocess, run_plugins_on_postprocess
 from calibre.ebooks.conversion.preprocess import HTMLPreProcessor
 from calibre.ptempfile import PersistentTemporaryDirectory
 from calibre import extract, walk
@@ -470,6 +471,14 @@ OptionRecommendation(name='language',
             self.log('Processing archive...')
             tdir = PersistentTemporaryDirectory('_plumber')
             self.input, input_fmt = self.unarchive(self.input, tdir)
+        if os.access(self.input, os.R_OK):
+            nfp = run_plugins_on_preprocess(self.input, input_fmt)
+            if nfp != self.input:
+                self.input = nfp
+                input_fmt = os.path.splitext(self.input)[1]
+                if not input_fmt:
+                    raise ValueError('Input file must have an extension')
+                input_fmt = input_fmt[1:].lower()
 
         if os.path.exists(self.output) and os.path.isdir(self.output):
             output_fmt = 'oeb'
@@ -842,6 +851,8 @@ OptionRecommendation(name='language',
         self.output_plugin.convert(self.oeb, self.output, self.input_plugin,
                 self.opts, self.log)
         self.ui_reporter(1.)
+        run_plugins_on_postprocess(self.output, self.output_fmt)
+
         self.log(self.output_fmt.upper(), 'output written to', self.output)
         self.flush()
 
diff --git a/src/calibre/ebooks/lrf/html/convert_from.py b/src/calibre/ebooks/lrf/html/convert_from.py
index ab32b313eb..3be8f85e45 100644
--- a/src/calibre/ebooks/lrf/html/convert_from.py
+++ b/src/calibre/ebooks/lrf/html/convert_from.py
@@ -12,7 +12,6 @@ from urllib import unquote
 from urlparse import urlparse
 from math import ceil, floor
 from functools import partial
-from calibre.customize.ui import run_plugins_on_postprocess
 
 try:
     from PIL import Image as PILImage
@@ -1938,7 +1937,6 @@ def process_file(path, options, logger):
         oname = os.path.join(os.getcwd(), name)
     oname = os.path.abspath(os.path.expanduser(oname))
     conv.writeto(oname, lrs=options.lrs)
-    run_plugins_on_postprocess(oname, 'lrf')
     conv.cleanup()
     return oname