diff --git a/frontend/document/djvudocument.lua b/frontend/document/djvudocument.lua
index 55d52ad26..fc58352d8 100644
--- a/frontend/document/djvudocument.lua
+++ b/frontend/document/djvudocument.lua
@@ -25,7 +25,6 @@ local function validDjvuFile(filename)
 end
 
 function DjvuDocument:init()
-    self:updateColorRendering()
     local djvu = require("libs/libkoreader-djvu")
     self.koptinterface = require("document/koptinterface")
     self.koptinterface:setDefaultConfigurable(self.configurable)
@@ -38,6 +37,7 @@ function DjvuDocument:init()
     if not ok then
         error(self._document)  -- will contain error message
     end
+    self:updateColorRendering()
     self.is_open = true
     self.info.has_pages = true
     self.info.configurable = true
diff --git a/frontend/document/document.lua b/frontend/document/document.lua
index 687f1c976..70649c5b9 100644
--- a/frontend/document/document.lua
+++ b/frontend/document/document.lua
@@ -387,14 +387,6 @@ function Document:updateColorRendering()
     end
 end
 
-function Document:preRenderPage()
-    return nil
-end
-
-function Document:postRenderPage()
-    return nil
-end
-
 function Document:getTileCacheValidity()
     return self.tile_cache_validity_ts
 end
@@ -407,15 +399,15 @@ function Document:resetTileCacheValidity()
     self.tile_cache_validity_ts = os.time()
 end
 
-function Document:getFullPageHash(pageno, zoom, rotation, gamma, render_mode, color)
+function Document:getFullPageHash(pageno, zoom, rotation, gamma, render_mode)
     return "renderpg|"..self.file.."|"..self.mod_time.."|"..pageno.."|"
-                    ..zoom.."|"..rotation.."|"..gamma.."|"..render_mode..(color and "|color" or "")
+                    ..zoom.."|"..rotation.."|"..gamma.."|"..render_mode..(self.render_color and "|color" or "|bw")
                     ..(self.reflowable_font_size and "|"..self.reflowable_font_size or "")
 end
 
 function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode, hinting)
     local hash_excerpt
-    local hash = self:getFullPageHash(pageno, zoom, rotation, gamma, render_mode, self.render_color)
+    local hash = self:getFullPageHash(pageno, zoom, rotation, gamma, render_mode)
     local tile = DocCache:check(hash, TileCacheItem)
     if not tile then
         hash_excerpt = hash.."|"..tostring(rect)
@@ -435,7 +427,6 @@ function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode, h
     if hinting then
         CanvasContext:enableCPUCores(2)
     end
-    self:preRenderPage()
 
     local page_size = self:getPageDimensions(pageno, zoom, rotation)
     -- this will be the size we actually render
@@ -493,7 +484,6 @@ function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode, h
     page:close()
     DocCache:insert(hash, tile)
 
-    self:postRenderPage()
     if hinting then
         CanvasContext:enableCPUCores(1)
     end
diff --git a/frontend/document/koptinterface.lua b/frontend/document/koptinterface.lua
index d79ff8f4d..ad774721a 100644
--- a/frontend/document/koptinterface.lua
+++ b/frontend/document/koptinterface.lua
@@ -169,6 +169,7 @@ function KoptInterface:getContextHash(doc, pageno, bbox, hash_list)
     local canvas_size = CanvasContext:getSize()
     table.insert(hash_list, doc.file)
     table.insert(hash_list, doc.mod_time)
+    table.insert(hash_list, doc.render_color and 'color' or 'bw')
     table.insert(hash_list, pageno)
     doc.configurable:hash(hash_list)
     table.insert(hash_list, bbox.x0)
diff --git a/frontend/document/pdfdocument.lua b/frontend/document/pdfdocument.lua
index 35e13f01c..72bc73230 100644
--- a/frontend/document/pdfdocument.lua
+++ b/frontend/document/pdfdocument.lua
@@ -21,12 +21,6 @@ local PdfDocument = Document:extend{
 
 function PdfDocument:init()
     if not pdf then pdf = require("ffi/mupdf") end
-    -- mupdf.color has to stay false for kopt to work correctly
-    -- and be accurate (including its job about showing highlight
-    -- boxes). We will turn it on and off in PdfDocument:preRenderPage()
-    -- and :postRenderPage() when mupdf is called without kopt involved.
-    pdf.color = false
-    self:updateColorRendering()
     self.koptinterface = require("document/koptinterface")
     self.koptinterface:setDefaultConfigurable(self.configurable)
     local ok
@@ -34,6 +28,7 @@ function PdfDocument:init()
     if not ok then
         error(self._document)  -- will contain error message
     end
+    self:updateColorRendering()
     self.is_reflowable = self._document:isDocumentReflowable()
     self.reflowable_font_size = self:convertKoptToReflowableFontSize()
     -- no-op on PDF
@@ -48,6 +43,13 @@ function PdfDocument:init()
     end
 end
 
+function PdfDocument:updateColorRendering()
+    Document.updateColorRendering(self) -- will set self.render_color
+    if self._document then
+        self._document:setColorRendering(self.render_color)
+    end
+end
+
 function PdfDocument:layoutDocument(font_size)
     if font_size then
         self.reflowable_font_size = font_size
@@ -81,14 +83,6 @@ function PdfDocument:convertKoptToReflowableFontSize(font_size)
     end
 end
 
-function PdfDocument:preRenderPage()
-    pdf.color = self.render_color
-end
-
-function PdfDocument:postRenderPage()
-    pdf.color = false
-end
-
 function PdfDocument:unlock(password)
     if not self._document:authenticatePassword(password) then
         return false
diff --git a/frontend/ui/widget/htmlboxwidget.lua b/frontend/ui/widget/htmlboxwidget.lua
index 447d89472..3b4b36291 100644
--- a/frontend/ui/widget/htmlboxwidget.lua
+++ b/frontend/ui/widget/htmlboxwidget.lua
@@ -84,18 +84,11 @@ function HtmlBoxWidget:_render()
     if self.bb then
         return
     end
-
-    -- In pdfdocument.lua, color is activated only at the moment of
-    -- rendering and then immediately disabled, for safety with kopt.
-    -- We do the same here.
-    Mupdf.color = Screen:isColorEnabled()
-
     local page = self.document:openPage(self.page_number)
+    self.document:setColorRendering(Screen:isColorEnabled())
     local dc = DrawContext.new()
     self.bb = page:draw_new(dc, self.dimen.w, self.dimen.h, 0, 0)
     page:close()
-
-    Mupdf.color = false
 end
 
 function HtmlBoxWidget:getSize()