diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 5face0b..508917f 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -3754,7 +3754,9 @@ let rasterize antialias downsample device res annots quality pdf range =
                [Pdftransform.Translate (tx, ty);
                 Pdftransform.Scale ((0., 0.), float_of_int w *. 72. /. res, float_of_int h *. 72. /. res);
                 Pdftransform.Rotate ((0., 0.), rotation)]);
-           Pdfops.Op_Do "/I0"]
+           Pdfops.Op_BMC "/Artifact";
+           Pdfops.Op_Do "/I0";
+           Pdfops.Op_EMC]
         in
         {page with Pdfpage.content = [Pdfops.stream_of_ops ops];
                    Pdfpage.resources = Pdf.Dictionary [("/XObject", Pdf.Dictionary [("/I0", Pdf.Indirect imageobj)])]})
@@ -4533,15 +4535,15 @@ let go () =
   | Some RemoveBookmarks ->
       write_pdf false (Pdfmarks.remove_bookmarks (get_single_pdf args.op false))
   | Some TwoUp ->
-      write_pdf false (Cpdfimpose.twoup args.fast (get_single_pdf args.op false))
+      write_pdf false (Cpdfimpose.twoup ~process_struct_tree:args.process_struct_trees args.fast (get_single_pdf args.op false))
   | Some TwoUpStack ->
-      write_pdf false (Cpdfimpose.twoup_stack args.fast (get_single_pdf args.op false))
+      write_pdf false (Cpdfimpose.twoup_stack ~process_struct_tree:args.process_struct_trees args.fast (get_single_pdf args.op false))
   | Some Impose fit ->
       let pdf = get_single_pdf args.op false in
       let x, y = Cpdfcoord.parse_coordinate pdf args.coord in
         if not fit && (x < 0.0 || y < 0.0) then error "Negative imposition parameters not allowed." else
         write_pdf false
-          (Cpdfimpose.impose ~x ~y ~fit ~columns:args.impose_columns ~rtl:args.impose_rtl ~btt:args.impose_btt ~center:args.impose_center
+          (Cpdfimpose.impose ~process_struct_tree:args.process_struct_trees ~x ~y ~fit ~columns:args.impose_columns ~rtl:args.impose_rtl ~btt:args.impose_btt ~center:args.impose_center
                       ~margin:args.impose_margin ~spacing:args.impose_spacing ~linewidth:args.impose_linewidth ~fast:args.fast pdf)
   | Some (StampOn over) ->
       let overpdf =
diff --git a/cpdfimpose.ml b/cpdfimpose.ml
index 46211df..fcc7a15 100644
--- a/cpdfimpose.ml
+++ b/cpdfimpose.ml
@@ -191,7 +191,8 @@ let add_border linewidth ~fast pdf =
       fast (w -. linewidth, h -. linewidth) (RGB (0., 0., 0.)) true linewidth 1. (Cpdfposition.BottomLeft (linewidth /. 2., linewidth /. 2.))
       false false (ilist 1 (Pdfpage.endpage pdf)) pdf
 
-let impose ~x ~y ~fit ~columns ~rtl ~btt ~center ~margin ~spacing ~linewidth ~fast pdf =
+let impose ~process_struct_tree ~x ~y ~fit ~columns ~rtl ~btt ~center ~margin ~spacing ~linewidth ~fast pdf =
+  let pdf = if process_struct_tree then Cpdfpage.mark_all_as_artifact pdf else pdf in
   let endpage = Pdfpage.endpage pdf in
   let pagenums = ilist 1 endpage in
   let pdf = Cpdfpage.copy_box "/CropBox" "/MediaBox" true pdf pagenums in
@@ -244,17 +245,17 @@ let impose ~x ~y ~fit ~columns ~rtl ~btt ~center ~margin ~spacing ~linewidth ~fa
   if fit then pdf else Cpdfpage.shift_pdf ~fast (many (margin, margin) (length pages)) pdf (ilist 1 (Pdfpage.endpage pdf))
 
 (* Legacy -twoup-stack. Impose 2x1 on a page twice the size then rotate. *)
-let twoup_stack fast pdf =
+let twoup_stack ~process_struct_tree fast pdf =
   let pdf =
     impose
-      ~x:2. ~y:1. ~fit:false ~columns:false ~rtl:false ~btt:false ~center:false
+      ~process_struct_tree ~x:2. ~y:1. ~fit:false ~columns:false ~rtl:false ~btt:false ~center:false
       ~margin:0. ~spacing:0. ~linewidth:0. ~fast pdf
   in
    let all = ilist 1 (Pdfpage.endpage pdf) in
     Cpdfpage.upright ~fast all (Cpdfpage.rotate_pdf ~-90 pdf all)
 
 (* Legacy -two-up. Rotate the pages and shrink them so as to fit 2x1 on a page the same size. *)
-let twoup fast pdf =
+let twoup ~process_struct_tree fast pdf =
   let firstpage = hd (Pdfpage.pages_of_pagetree pdf) in
   let width, height =
     match Pdf.parse_rectangle pdf firstpage.Pdfpage.mediabox with
@@ -271,7 +272,7 @@ let twoup fast pdf =
         let pdf = Cpdfpage.scale_pdf ~fast (many (sc, sc) endpage) pdf all in
         let pdf =
           impose
-            ~x:2. ~y:1. ~fit:false ~columns:false ~rtl:false ~btt:false ~center:true
+            ~process_struct_tree ~x:2. ~y:1. ~fit:false ~columns:false ~rtl:false ~btt:false ~center:true
             ~margin:0. ~spacing:0. ~linewidth:0. ~fast pdf
         in
         let endpage = Pdfpage.endpage pdf in
diff --git a/cpdfimpose.mli b/cpdfimpose.mli
index 605fcb1..011612b 100644
--- a/cpdfimpose.mli
+++ b/cpdfimpose.mli
@@ -1,13 +1,13 @@
 (** Imposition *)
 
 (** Imposition. See cpdfmanual.pdf for details. *)
-val impose : x:float -> y:float -> fit:bool -> columns:bool -> rtl:bool -> btt:bool -> center:bool -> margin:float -> spacing:float -> linewidth:float -> fast:bool -> Pdf.t -> Pdf.t
+val impose : process_struct_tree:bool -> x:float -> y:float -> fit:bool -> columns:bool -> rtl:bool -> btt:bool -> center:bool -> margin:float -> spacing:float -> linewidth:float -> fast:bool -> Pdf.t -> Pdf.t
 
 (** The legacy twoup_stack operation puts two logical pages on each physical page,
 rotating them 90 degrees to do so. The new mediabox is thus larger. Bool true
 (fast) if assume well-formed ISO content streams. *)
-val twoup_stack : bool -> Pdf.t -> Pdf.t
+val twoup_stack : process_struct_tree:bool -> bool -> Pdf.t -> Pdf.t
 
 (** The legacy twoup operation does the same, but scales the new sides down so that
 the media box is unchanged. Bool true (fast) if assume well-formed ISO content streams. *)
-val twoup : bool -> Pdf.t -> Pdf.t
+val twoup : process_struct_tree:bool -> bool -> Pdf.t -> Pdf.t