diff --git a/Makefile b/Makefile
index 1bd2544..ca91a5f 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@
 MODS = cpdfyojson cpdfxmlm \
        cpdfunicodedata cpdferror cpdfjson cpdfstrftime cpdfcoord cpdfattach \
        cpdfpagespec cpdfposition cpdf cpdfpresent cpdffont cpdftype \
-       cpdftexttopdf cpdftoc cpdfcommand
+       cpdftexttopdf cpdftoc cpdfpad cpdfcommand
 
 SOURCES = $(foreach x,$(MODS),$(x).ml $(x).mli) cpdfcommandrun.ml
 
diff --git a/cpdf.ml b/cpdf.ml
index d86b0f1..5676d98 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -1625,107 +1625,6 @@ let removetext range pdf =
       in
         process_pages (ppstub removetext_page) pdf range
 
-(* \section{Padding with blank pages.} *)
-let insert_after pos page pages =
-  let before, after = cleave pages pos in
-    before @ [page] @ after
-
-(* Insert many. *)
-let rec insert_after_many pages = function
-  | [] -> pages
-  | (pos, page)::more ->
-      let pages' = insert_after pos page pages in
-        insert_after_many pages' (map (fun (p, pa) -> p + 1, pa) more)
-
-(* For each pagenum in the range, increment the count by padsize, and carry on. e.g
-insert_after_many_changes 1 0 [2] [1; 2; 3] --> [(1, 1); (2, 2); (3, 4)] *)
-let rec insert_after_many_changes isbefore padsize offset range = function
-  [] -> []
-| h::t ->
-    let item = (h, h + offset + if isbefore && mem h range then 1 else 0) in
-      if mem h range then
-        item::insert_after_many_changes isbefore padsize (offset + padsize) range t
-      else
-        item::insert_after_many_changes isbefore padsize offset range t
-
-let print_changes =
-  iter (fun (f, t) -> Printf.printf "%i --> %i\n" f t)
-
-let pad_with_pdf (range : int list) (pdf : Pdf.t) (isbefore : bool) (padfile : Pdf.t) =
-  let range = sort compare (setify range) in
-  let merged =
-    Pdfmerge.merge_pdfs
-      false false ["a"; "b"] [pdf; padfile] [ilist 1 (Pdfpage.endpage pdf); ilist 1 (Pdfpage.endpage padfile)]
-  in
-  let original_pages, padpages =
-    cleave (Pdfpage.pages_of_pagetree merged) (Pdfpage.endpage pdf) 
-  in
-    let newpages =
-      map
-        (fun (pagenum, page) ->
-           if mem pagenum range then
-             (if isbefore then padpages @ [page] else [page] @ padpages)
-           else
-             [page])
-        (combine (indx original_pages) original_pages)
-    in
-      (* FIXME Provide ~changes here? *)
-      Pdfpage.change_pages false merged (flatten newpages)
-
-let pad padwith range pdf isbefore =
-  match padwith with
-    Some padfile -> pad_with_pdf range pdf isbefore padfile
-  | None ->
-      let i = if isbefore then 1 else 0 in
-      let pages = Pdfpage.pages_of_pagetree pdf in
-        let blankpages =
-          map
-            (fun n ->
-               {Pdfpage.content = [];
-                Pdfpage.mediabox = (select (n + i) pages).Pdfpage.mediabox;
-                Pdfpage.resources = Pdf.Dictionary [];
-                Pdfpage.rotate = (select (n + i) pages).Pdfpage.rotate;
-                Pdfpage.rest = Pdf.remove_dict_entry ((select (n + i) pages).Pdfpage.rest) "/Annots"})
-            range
-        in
-          let pages' = insert_after_many pages (combine range blankpages) in
-          let changes =
-            insert_after_many_changes
-              isbefore 1 0 (map (fun x -> x + i) range) (ilist 1 (length pages))
-          in
-            Pdfpage.change_pages ~changes true pdf pages'
-
-let padafter ?padwith range pdf =
-  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
-    if not (fold_left ( && ) true (map isinpdf range)) then
-      raise (Failure "padafter: range contains pages not present in pdf");
-    pad padwith range pdf false
-
-let padbefore ?padwith range pdf =
-  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
-    if not (fold_left ( && ) true (map isinpdf range)) then
-      raise (Failure "padbefore: range contains pages not present in pdf");
-    pad padwith (map pred range) pdf true
-
-let padmultiple n pdf =
-  let neg, n = n < 0, if n < 0 then -n else n in
-  let pages = Pdfpage.pages_of_pagetree pdf in
-    let len = length pages in
-      let pages_to_add = if len / n * n = len then 0 else n - (len mod n) in
-        if pages_to_add > 0 then
-          let blankpages =
-            many
-              {Pdfpage.content = [];
-               Pdfpage.mediabox = (select len pages).Pdfpage.mediabox;
-               Pdfpage.resources = Pdf.Dictionary [];
-               Pdfpage.rotate = (select len pages).Pdfpage.rotate;
-               Pdfpage.rest = Pdf.Dictionary []}
-              pages_to_add
-          in
-            let changes = map (fun x -> (x, x)) (ilist 1 (length pages)) in
-              Pdfpage.change_pages ~changes true pdf (if neg then blankpages @ pages else pages @ blankpages)
-        else
-          pdf
 
 (* \section{Shift page data} *)
 let make_mediabox (xmin, ymin, xmax, ymax) =
diff --git a/cpdf.mli b/cpdf.mli
index 063c193..7262dcf 100644
--- a/cpdf.mli
+++ b/cpdf.mli
@@ -285,16 +285,6 @@ val trim_marks : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 
 val show_boxes : ?fast:bool -> Pdf.t -> int list -> Pdf.t
 
-(** {2 Padding} *)
-
-(** Put blank pages before the given page numbers *)
-val padbefore : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
-
-(** Put blank pages after the given page numbers *)
-val padafter : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
-
-(** Pad to a multiple of n pages *)
-val padmultiple : int -> Pdf.t -> Pdf.t
 
 (** {2 Annotations} *)
 
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index 11c148f..1347405 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -3576,7 +3576,7 @@ let go () =
               None -> None
             | Some filename -> Some (pdfread_pdf_of_file None None filename)
           in
-            write_pdf false (Cpdf.padbefore ?padwith range pdf)
+            write_pdf false (Cpdfpad.padbefore ?padwith range pdf)
   | Some PadAfter ->
       let pdf = get_single_pdf args.op false in
         let range = parse_pagespec_allow_empty pdf (get_pagespec ()) in
@@ -3585,7 +3585,7 @@ let go () =
               None -> None
             | Some filename -> Some (pdfread_pdf_of_file None None filename)
           in
-            write_pdf false (Cpdf.padafter ?padwith range pdf)
+            write_pdf false (Cpdfpad.padafter ?padwith range pdf)
   | Some (PadEvery n) ->
       let pdf = get_single_pdf args.op false in
         let range =
@@ -3598,13 +3598,13 @@ let go () =
               None -> None
             | Some filename -> Some (pdfread_pdf_of_file None None filename)
           in
-            write_pdf false (Cpdf.padafter ?padwith range pdf)
+            write_pdf false (Cpdfpad.padafter ?padwith range pdf)
   | Some (PadMultiple n) ->
       let pdf = get_single_pdf args.op false in
-        write_pdf false (Cpdf.padmultiple n pdf)
+        write_pdf false (Cpdfpad.padmultiple n pdf)
   | Some (PadMultipleBefore n) ->
       let pdf = get_single_pdf args.op false in
-        write_pdf false (Cpdf.padmultiple (-n) pdf)
+        write_pdf false (Cpdfpad.padmultiple (-n) pdf)
   | Some Draft ->
       let pdf = get_single_pdf args.op false in
         let range = parse_pagespec_allow_empty pdf (get_pagespec ()) in
diff --git a/cpdfpad.ml b/cpdfpad.ml
new file mode 100644
index 0000000..43799b8
--- /dev/null
+++ b/cpdfpad.ml
@@ -0,0 +1,104 @@
+open Pdfutil
+
+(* \section{Padding with blank pages.} *)
+let insert_after pos page pages =
+  let before, after = cleave pages pos in
+    before @ [page] @ after
+
+(* Insert many. *)
+let rec insert_after_many pages = function
+  | [] -> pages
+  | (pos, page)::more ->
+      let pages' = insert_after pos page pages in
+        insert_after_many pages' (map (fun (p, pa) -> p + 1, pa) more)
+
+(* For each pagenum in the range, increment the count by padsize, and carry on. e.g
+insert_after_many_changes 1 0 [2] [1; 2; 3] --> [(1, 1); (2, 2); (3, 4)] *)
+let rec insert_after_many_changes isbefore padsize offset range = function
+  [] -> []
+| h::t ->
+    let item = (h, h + offset + if isbefore && mem h range then 1 else 0) in
+      if mem h range then
+        item::insert_after_many_changes isbefore padsize (offset + padsize) range t
+      else
+        item::insert_after_many_changes isbefore padsize offset range t
+
+let print_changes =
+  iter (fun (f, t) -> Printf.printf "%i --> %i\n" f t)
+
+let pad_with_pdf (range : int list) (pdf : Pdf.t) (isbefore : bool) (padfile : Pdf.t) =
+  let range = sort compare (setify range) in
+  let merged =
+    Pdfmerge.merge_pdfs
+      false false ["a"; "b"] [pdf; padfile] [ilist 1 (Pdfpage.endpage pdf); ilist 1 (Pdfpage.endpage padfile)]
+  in
+  let original_pages, padpages =
+    cleave (Pdfpage.pages_of_pagetree merged) (Pdfpage.endpage pdf) 
+  in
+    let newpages =
+      map
+        (fun (pagenum, page) ->
+           if mem pagenum range then
+             (if isbefore then padpages @ [page] else [page] @ padpages)
+           else
+             [page])
+        (combine (indx original_pages) original_pages)
+    in
+      (* FIXME Provide ~changes here? *)
+      Pdfpage.change_pages false merged (flatten newpages)
+
+let pad padwith range pdf isbefore =
+  match padwith with
+    Some padfile -> pad_with_pdf range pdf isbefore padfile
+  | None ->
+      let i = if isbefore then 1 else 0 in
+      let pages = Pdfpage.pages_of_pagetree pdf in
+        let blankpages =
+          map
+            (fun n ->
+               {Pdfpage.content = [];
+                Pdfpage.mediabox = (select (n + i) pages).Pdfpage.mediabox;
+                Pdfpage.resources = Pdf.Dictionary [];
+                Pdfpage.rotate = (select (n + i) pages).Pdfpage.rotate;
+                Pdfpage.rest = Pdf.remove_dict_entry ((select (n + i) pages).Pdfpage.rest) "/Annots"})
+            range
+        in
+          let pages' = insert_after_many pages (combine range blankpages) in
+          let changes =
+            insert_after_many_changes
+              isbefore 1 0 (map (fun x -> x + i) range) (ilist 1 (length pages))
+          in
+            Pdfpage.change_pages ~changes true pdf pages'
+
+let padafter ?padwith range pdf =
+  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
+    if not (fold_left ( && ) true (map isinpdf range)) then
+      raise (Failure "padafter: range contains pages not present in pdf");
+    pad padwith range pdf false
+
+let padbefore ?padwith range pdf =
+  let isinpdf n = mem n (ilist 1 (Pdfpage.endpage pdf)) in
+    if not (fold_left ( && ) true (map isinpdf range)) then
+      raise (Failure "padbefore: range contains pages not present in pdf");
+    pad padwith (map pred range) pdf true
+
+let padmultiple n pdf =
+  let neg, n = n < 0, if n < 0 then -n else n in
+  let pages = Pdfpage.pages_of_pagetree pdf in
+    let len = length pages in
+      let pages_to_add = if len / n * n = len then 0 else n - (len mod n) in
+        if pages_to_add > 0 then
+          let blankpages =
+            many
+              {Pdfpage.content = [];
+               Pdfpage.mediabox = (select len pages).Pdfpage.mediabox;
+               Pdfpage.resources = Pdf.Dictionary [];
+               Pdfpage.rotate = (select len pages).Pdfpage.rotate;
+               Pdfpage.rest = Pdf.Dictionary []}
+              pages_to_add
+          in
+            let changes = map (fun x -> (x, x)) (ilist 1 (length pages)) in
+              Pdfpage.change_pages ~changes true pdf (if neg then blankpages @ pages else pages @ blankpages)
+        else
+          pdf
+
diff --git a/cpdfpad.mli b/cpdfpad.mli
new file mode 100644
index 0000000..ba599a0
--- /dev/null
+++ b/cpdfpad.mli
@@ -0,0 +1,10 @@
+(** {2 Padding} *)
+
+(** Put blank pages before the given page numbers *)
+val padbefore : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
+
+(** Put blank pages after the given page numbers *)
+val padafter : ?padwith:Pdf.t -> int list -> Pdf.t -> Pdf.t
+
+(** Pad to a multiple of n pages *)
+val padmultiple : int -> Pdf.t -> Pdf.t