Compare PDF documents
Find easily differences with Kiwi tool to compare PDF documents. This
will allow you:
- Compare both content (text and images) and appearance
(pixel by pixel), depending on the mode chosen. It is remarkable
that not only compares texts, but also compares images.
- Distinguish what types of changes have occurred in each
case: modifications, insertions, deletions or displacements. This
brings comparisons to the highest level of accuracy.
- Choose what to compare within documents: what pages
compare and what part of them. You can for example leave headers,
footers or side annotations out of the comparison that often cause
- Review the results incredibly easily and quickly: with
just one click you go from one change to the next, you do not have
to walk around looking at what pages there are changes and where,
these are grouped and displayed one after another. It will save a
lot of your time!
These instructions correspond to the PRO version of the program. Some
of the capabilities discussed here may not exist in other versions.
You can see the limitations of each version on the main download page
of those versions.
How to compare PDF documents
To compare PDF documents follow the following steps:
1. Load files you are going to compare clicking the Open
file buttons located in the top left corner of every
document panel, and looking for them in the folder tree. Only files
with PDF extensions are going to be shown.
Once both files have been loaded, they should be shown in both
- You can choose if you want to see them in an horizontal layout,
with one document at left and the other one at right, or in a
vertical layout, with one document at top and the other one at the
bottom (click Change windows distribution for this).
- You can navigate through the documents using the navigation
buttons (forward, back, zoom, etc.) and the scrolls.
- The second window scroll movement can be locked to the first
window scroll movement using Synchro button. This
will make it easier to visually compare documents.
2. If desired, change comparison settings choosing Options
> Comparing options and selecting the desired options
in the menus. First of all, you have to decide the comparison mode:
- Content: In this mode Kiwi will compare text and
images content, no matter in which pages that information is found
or the format in which they are.
- Appearance: In this mode Kiwi will compare the
complete appearance of both documents, page by page, pixel by pixel.
All visual differences between pages are going to be shown in this
Every mode has specific options:
Content mode settings:
- Number of characters between changes to be considered as a
single global change box. If there is identical text
between two changes that exceeds this number of characters, both
changes will be considered different, and presented within different
boxes. In other case everything will be considered a same change and
included within the same box.
- Number of characters between changes to be considered as a
single individual highlighted change. If there is
identical text between two changes whose length is less or equal
than this number of characters, this identical characters are going
to be highlighted too as changed, otherwise not.
- How to consider text movements. You can decide if
consider it as not changed text, as not differentiated changed text
(highlighted), or as differentiated changed text (underlined).
- How to consider insertions/deletions where empty.
You can mark the point in the new version of the document where a
deleted text was in the old version, or the point of the old version
in which a new text has been inserted, or the point of origin of a
text that It has moved. These empty spaces can be considered as not
changed text (no marks at this point), as not differentiated changed
text (highlighted) or as differentiated changed text (marked with an
Appearance mode settings:
- Geometric detection tolerance: If in the second
document it is found and identical pixel at a distance less than
this number of pixels from the pixel in the first document, it will
not be considered a change. It is useful to avoid the differences
resulting from small displacements of the elements in the images.
- Color detection tolerance: If the changes in RGB
color values are less than these quantities, the pixels will be
considered identical. It is useful for images with slight
differences in color tone.
3. Select the part of the documents you are going to compare:
- Select the range of pages to be compared by
filling in the corresponding fields in the top bar of the panels of
each file. In Appearance comparison mode the resultant number of
pages to be compared should be the same in both documents, as it´s a
page to page comparison, but in Content comparison mode can be a
- Select the regions within the pages to be compared
by sliding the small boxes at the corners of the documents. It´s
only allowed in the Content comparison mode, and region selected is
going to be applied to the whole document. With this you can leave
out of the comparison headers, footers and side annotations.
4. Click Compare button to compare both PDF
documents. After the process is finished, all differences detected are
going to be shown on both documents, and the first of them will be
shown within a box.
5. You can navigate from one difference to the next by
clicking the Next difference button or to the previous
by clicking the Previous difference button.
6. The appearance of the elements added to the documents in
the comparison can be modified by selecting Options >
Appearance options. Here you can change colors, dimensions
and other characteristics of the information showed by Kiwi over the
documents. The changes applied here will be effective both in the
visualization of the documents in Kiwi, and in the printing of the
same ones that are done from that moment with this program.
7. Results can be printed by clicking Print
buttons located in both document panel top bars. Here you can decide
if the boxes that frame differences are going to be shown or not, and
if the generated documents are going to contain all the pages of the
document or only the changed ones.