Cropping Pages for Clarity

Aggressive page cropping ensures maximum on-screen clarity.

When viewing a PDF in Reader or Acrobat, the page is often scaled to fit its width or its height into the viewer window. This means you can make page content appear larger on-screen by cropping away excess page margins. Cropping has no effect on the printed page's scale, but it might alter the content's position on the printed page.
Acrobat's cropping tool can remove excess page margins. Use it in combination with our freely available BBOX Acrobat plug-in. These two tools make it easy to find the best cropping for a page and then apply this cropping to the entire document.

Rasterize Drawings In-Place with Acrobat

First, make a backup copy of your PDF so that you can go back to where you started at any time.
Open your PDF in Acrobat and locate the drawing you want to rasterize. Activate the TouchUp Object tool (Tools >Advanced Editing >TouchUp Object, in Acrobat 6) and try to select the drawing. This usually requires patience and experimentation because one illustration might use dozens of separate drawing objects. And, it usually is tangled with other items on the page that you don't want to rasterize.
First, try dragging out a selection rectangle that encloses the artwork. If other, unwanted items get caught in your dragnet, try dropping them from your selection by holding down the Shift key and clicking them. If you missed items that you wanted to select, you can add them the same way: Shift-click. The Shift key is a useful way to incrementally add or remove items from your current selection. You can even hold down the Shift key while dragging out a selection rectangle. Items in the rectangle will be toggled in or out of the current selection, depending on their previous state.
If you accidentally move an item, immediately press Ctrl-Z (Edit >Undo) to restore it. If things ever get messed up, close the PDF without saving it and reopen it to start again.

Using Photoshop for Rasterizing Intricate Artwork

If you are using Photoshop instead of Illustrator, you won't have a chance to select the objects you want rasterized; Photoshop immediately rasterizes everything you selected in Acrobat. One advantage of using Photoshop is that it won't try to substitute fonts, as Illustrator sometimes does.

After your selection is made in Acrobat, right-click inside the selection and click Edit Objects . . . . Photoshop will open and ask you for a resolution. Enter a resolution (e.g., 300 pixels per inch), click OK, and the rasterized results will appear. Inspect the results to make sure the artwork retained adequate detail. If you like the results, save the Photoshop file. By default, it should save as PDF, but sometimes you must change the Format to PDF in the Save dialog. Before saving the file, Photoshop will ask which encoding to use (ZIP or JPEG). If you choose JPEG, you can also set its quality level. After saving the rasterized artwork in Photoshop, Acrobat will automatically update the PDF to reflect your changes. If you still like them, save the PDF in Acrobat. Otherwise, discard them by pressing Ctrl-Z (Edit>Undo) or by closing the PDF in Acrobat and starting over.

Using Illustrator for Rasterizing Intricate Artwork

After your selection is made in Acrobat, right-click inside the selection and click Edit Objects . . . . Adobe Illustrator will open and your selected material will appear. Now, you must select the items you want to rasterize. If your selection in Acrobat worked just right, you can simply select the entire page (Edit >Select All). If your original selection included unwanted items, carefully omit these items from this new selection. The Shift key works the same way in Illustrator as it did in Acrobat, as you assemble your selection.
After making your selection in Illustrator, select Object >Rasterize . . . and a dialog opens. Select a suitable color model (e.g., RGB) and resolution (e.g., 300 pixels per inch) and click OK. Inspect the results to make sure the artwork retained adequate detail. If you like the results, save and close the Illustrator file. Acrobat will automatically update the PDF to reflect your changes. If you still like them, save the PDF in Acrobat. Otherwise, discard them by pressing Ctrl-Z (Edit >Undo) or by closing the PDF and starting over.

Preparation for Rasterizing Intricate Artwork

When distributing a PDF online, some vector drawings outweigh their usefulness.

Vector drawings yield the highest possible quality across all media. For simple illustrations such as charts and graphs, they are also more efficient than bitmaps. However, when preparing a PDF for online distribution, you will sometimes find an intricate vector drawing that has tripled your PDF's file size. With Acrobat and Illustrator (or Photoshop), you can rasterize this detailed drawing in-place and reduce your PDF's file size.

Big Drawings in Little Spaces
How does this happen? Vector artwork scales easily without altering its quality. This means a big, detailed, 2 MB vector drawing can be scaled down perfectly to the size of a postage stamp. Even though most of its detail might no longer be visible on a paper printout or on-screen, the drawing is still 2MB in size. Again, this becomes an issue only when you go to distribute this file online and you want to reduce the document's file size.

Rasterize Intricate Artwork
If you have Adobe Acrobat 6 Pro or Acrobat 5 and Adobe Illustrator or Adobe Photoshop, you can rasterize a PDF's drawings. First you must configure Acrobat's TouchUp Object tool to open your PDF selections in Illustrator or Photoshop.

In Acrobat, select Edit >Preferences >General . . . TouchUp. Click Choose Page/Object Editor and then browse over to Illustrator.exe, which might be located somewhere such as C:\Program Files\Adobe\Illustrator 9.0.1\. Or, use Photoshop instead of Illustrator by browsing over to Photoshp.exe, which might be located somewhere such as C:\Program Files\Adobe\Photoshop 6.0\. Click Open and then click OK to confirm your new Preferences setting.

Improvement

Pass the name of your PDF document and the kw_catcher window size to make_index.sh like so:

make_index.sh mydoc.pdf 12

The script will create a document index named mydoc.index.pdf. Review this index and append it to your PDF document if you desire. The script also creates two intermediate files: mydoc.data.txt and mydoc.txt. If the PDF index is faulty, review these intermediate files for problems. Delete them when you are satisfied with the PDF index.

The second argument to make_index.sh controls the keyword detection sensitivity. Smaller numbers yield fewer keywords at the risk of omitting some keywords; larger numbers admit more keywords and also more noise.

The Code

Of course, the thing to do is to wrap this procedure into a tidy script. Copy the following Bourne shell script into a file named make_index.sh, and make it executable by applying chmod 700. Windows users can get a Bourne shell by installing MSYS .

#!/bin/sh

# make_index.sh, version 1.0

# usage: make_index.sh

# requires: pdftk, kw_catcher, page_refs,

# pdftotext, enscript, ps2pdf

#

# by Ross Presser, Imtek.com

# adapted by Sid Steward

# http://www.pdfhacks.com/kw_index/

fname=`basename $1 .pdf`

pdftk ${fname}.pdf dump_data output ${fname}.data.txt && \

pdftotext ${fname}.pdf ${fname}.txt && \

kw_catcher $2 keywords_only ${fname}.txt \

| page_refs ${fname}.txt - ${fname}.data.txt \

| enscript --columns 2 --font 'Times-Roman@10' \

--header '|INDEX' --header-font 'Times-Bold@14' \

--margins 54:54:36:54 --word-wrap --output - \

| ps2pdf - ${fname}.index.pdf