Troubleshooting

Improve fax quality

Tips for crisp and easily readable faxes

Tested solutions

Fixed quickly

Quick diagnosis

Quick tip

Low resolution, wrong format or poor contrast

Use PDF format, choose high contrast (black text on a white background), font size at least 10 pt.

Quick check

Check these points first

Document saved as PDF?
Black text on a white background?
Font size at least 10 point?
Resolution at least 200 DPI?
Page margins sufficient (at least 1.5 cm)?

Possible causes and solutions

Click a cause to see the solution

1

Text is blurry or pixelated

Cause

Resolution too low or compressed image

Symptoms

Letters are hard to read, edges are not sharp

Solution

Create the document at a minimum of 200 DPI. Use PDF instead of JPEG for text documents.

2

Greys are too dark or too light

Cause

Fax machines can only represent greyscale to a limited extent

Symptoms

Photos or graphics are barely recognisable

Solution

Increase the contrast. Faxes work best with black and white documents. Avoid photos or convert them into high-contrast graphics.

3

Margins are cut off

Cause

Page margins too small, recipient fax machine prints with different margins

Symptoms

Text at the page edge is missing

Solution

Use margins of at least 1.5 cm on all sides. Do not place important information at the very edge.

4

Font too small to read

Cause

Font size below 10 point, fine details are lost

Symptoms

Text is illegible after faxing

Solution

Use at least 10 pt font size, preferably 12 pt. Avoid thin or ornate typefaces.

How to prevent the issue

PDF is the best format for faxes - formatting is preserved and quality is optimal.
Avoid coloured backgrounds - faxes are transmitted in black and white.
Scan paper documents at a minimum of 200 DPI in black and white.

A clearly legible fax creates a professional impression. With these tips you can ensure that your faxes arrive in optimal quality.

The optimal document

For the best fax quality, your document should have these characteristics:

Format: PDF preferred
Contrast: black text on a white background
Font size: at least 10 pt, preferably 12 pt
Typeface: clear, easy-to-read font (Arial, Times New Roman)
Resolution: 200-300 DPI

Scanning paper documents properly

If you want to fax a paper document:

Scan mode: black and white or greyscale (not colour)
Resolution: 200 DPI minimum, 300 DPI for best quality
Format: save as PDF
Alignment: place straight, skewed scans are harder to read

Avoid common mistakes

These mistakes often lead to poor fax quality:

Coloured backgrounds: often become too dark or illegible
Photos: often do not come out well - avoid if possible
Small fonts: anything below 10 pt becomes hard to read
Thin lines: can disappear or appear broken

Frequently asked questions

Which file format delivers the best fax quality?

PDF delivers the best quality for faxes. The format preserves formatting, fonts and layout exactly. JPG and PNG also work, but PDF is optimal for text documents.

What resolution should I use?

At least 200 DPI (dots per inch). For very detailed documents or small fonts, 300 DPI is better. Higher resolutions offer little benefit because fax machines have a limited resolution.

Are colours transmitted?

No, faxes are generally transmitted in black and white or greyscale. Coloured content is automatically converted to greyscale. Check in advance whether your document is also easy to read in black and white.

Problem still not solved?

If none of the solutions worked, it may be a technical issue. Our support team will be happy to help.

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