Reducing file size

Nixt PDF offers two ways to make a document smaller, and keeps them apart on purpose:

• Make it smaller removes only what carries no information. Nothing you can see changes.
• Shrink the pictures redraws photographs with fewer pixels. It throws detail away, and says so before it does.

Where the size goes

1. On the Protect tab, click Reduce the size… (or choose More › Size…).
2. The Size dialog opens with the document’s total size at the top.

Below it, a bar for each kind of content shows how much of the file it takes, largest first:

Making it smaller without losing anything

Under the bars, the dialog says how much can come off, worked out by actually writing the smaller file rather than estimated — for example 340 KB can come off: earlier versions, objects nothing points at, and 3 streams stored uncompressed. Measured, not estimated.

When nothing can come off, it says There is nothing to take off without re-encoding what is in the document.

To make it smaller:

1. Click Make it smaller. It’s dimmed when there is nothing to save.
2. The message says, for example, Saved 340 KB — 2.1 MB down to 1.8 MB.
3. Save the document; see Saving your work.

What it does:

• Drops earlier versions of the document kept in the file.
• Removes objects nothing in the document uses any more.
• Compresses parts of the file that were stored uncompressed.

Pictures and fonts are left as they are. For most documents, most of the size is in pictures and fonts.

Because the file is rewritten, the undo history is cleared and this can’t be undone. A password-protected document keeps its password, and digital signatures stop matching.

Shrinking the pictures

When more than half the file is pictures and fonts, the Size dialog says so, and offers Shrink the pictures anyway….

1. In the Size dialog, click Shrink the pictures anyway….
2. In the Shrink the pictures dialog, drag Draw them at to the resolution you want, from 72 to 300 dpi. It starts at 150 dpi. The line under it says what suits:
   • 96 dpi or less: Fine on a screen. Visibly soft on paper.
   • between: Sharp on a screen and still decent on paper.
   • 250 dpi or more: Near print quality, and not much of a saving.
3. Read the list. It says how many pictures will shrink and how much of the file they take now, such as 4 of 9 pictures, 1.6 MB of the file:, then each picture by page:
   • pictures that will shrink show their size and resolution now and what they’ll become, such as 2400×3200 at 300 dpi → 1200 wide, about 150 dpi;
   • pictures left alone show why: already at or below the target, not a JPEG — re-encoding it would mean decoding a format Nixt PDF does not encode, too small for the saving to be worth the loss, or could not be read out of the file.
4. Click Shrink them. It’s dimmed when nothing will shrink. It reads Shrinking… and shows progress while it works.

When it finishes, the message says, for example, Shrank 4 pictures and the file with them — saved 1.2 MB, 3.4 MB down to 2.2 MB.

• Shrinking works on JPEG pictures.
• If the rewritten file wouldn’t be smaller, nothing is changed, and the message says Shrank 4 pictures, but the file did not get smaller. Nothing has been changed.
• No picture was worth shrinking. means no picture was above the target resolution.

Related pages

• Pictures on the page — see each picture’s resolution, and replace or remove pictures.
• Hidden content — take out attached files, earlier versions and other hidden content.