Understanding Compare Results

This article explains what you see in the Changes list in Compare Versions and answers the questions that come up most.

What counts as a change

Compare makes two checks and puts the results in one list.

• Text: it reads the words in both versions and marks what was added, removed or reworded.
• Appearance: it lays the two pages over each other and marks every area that looks different. In the list these are called Graphic change.

When a change to the words also changes how the page looks, it is listed once.

Why is one edit listed as several changes?

Compare groups differences that sit close together. Letters join into words, and words into lines, so a new sentence is one change. Differences that are further apart are listed separately, because Compare cannot know they belong to the same edit.

You may see this with:

• a barcode, which can come out as two or three pieces
• two parts of the same sentence with a wide gap between them
• a box or shape that moved slightly, which can show as its edges

The count at the top of the list is the number of marked areas. It is a guide to how much has changed, not an exact count of edits.

Why is a large area one change?

When a whole area changes, such as a panel that is now a different colour, Compare lists it as one change covering that area. Smaller changes inside it are part of the same entry. Use the Heatmap or Overlay view to look inside it. See Compare views.

The Alignment section

Before it compares how two pages look, Compare lines them up. The Alignment section at the top of the Changes list shows what it did.

• Offset, Rotation and Scale show whether the newer page had to be moved, turned or resized to match the older one. For two files exported the same way these are zero.
• Confidence shows how sure Compare is that the pages are lined up. 1 is certain.

If Compare is not sure the pages line up, it shows a warning. Some of the changes listed may then be the two pages sitting slightly apart, not real differences. Check that both versions are the same layout and page size.

What Compare does not check

• whether a colour matches a brand or print standard
• whether a barcode scans
• braille
• spelling or grammar
• changes to formatting in a document, such as font or bold, unless they change how the page looks

Images and scans

A JPEG, PNG or scanned page has no words that Papercurve can read, so it is compared on appearance only. Every difference is a Graphic change, and you will not see red and green text highlights.

Two files of the same image saved in different ways can show faint differences around edges. If the list fills with tiny changes you cannot see, switch to Heatmap and raise the Threshold slider.

Good to know

• Every area marked is a place where the two versions really differ. Compare does not hide differences.
• Parts of the page that change every time, such as lot numbers, can be left out with ignore zones.