How to get rid of writer document background image fine grid lines

I mande a picture to use as background image with the hole marks for my leverarch, a leverarch watermark if you will. I cannot however get rid of the fine grid that writer adds to the document because of the image as background. The picture itself does not contain any other marks nor shows on paper any grid lines when printed directly but, when I print the document with writer there is a fine grid covering almost the whole page.

I tried to play with the transparency setting (format->page->select transparency tab). In writer itself it seems to work kind of but, when I export the document as pdf (which I desperately needs) the grid lines shows again as if no transparency were added/adjusted.

How can I get rid of those gridlines added by writer due to the use of an image as background or, is there any other way to add a watermark to the document for my leverarch holes?
Here is a sample file:
Water mark sample file.odt

Hello @cpc3, Please, edit your question, and use the paper clip to share a sample file. Thanks.

Are you working with Asian language support enabled? See the last paragraph at LibreOffice Help on Text Grid.

EDIT: Text Grid are like rows of squares, so definitely this is not the issue. Reposting as a comment.

I see no problems when I export the document to PDF; even with no transparency.

Tested with LibreOffice (x86); OS: Windows 6.1.

Add Answer is reserved for solutions. Click edit (below your question) to add more information. Thanks.

I don’t see any artefacts even at high magnification. I exported to PDF and displayed it on screen at 10000% (x100) without “grid lines”. All I see is a uniform colour.

I can’t analyse the picture itself because it is not individualised as a file. The XML shows there are 5 previous version images names Leverarch Watermark, Leverarch%20Watermark, Painted White, Watermark%20test and water%20mark. Don’t worry about the %xx, it the way LO protects itself against possible character conflict in names by using URL %-encoding. Here %20 means “space”. There is another occurrence of an image directly in the page style and this seems to reference Leverarch%20Watermark.

The page style properties in Writer show you added a bitmap image (but I can’t extract it as already mentioned). This is probably the source of your problem. Bitmaps have a dpi resolution set when they are created. If this dpi do not match the dpi resolution of your printer, scaling occurs. Bitmaps are not vector images. This means they are made of pixels and these pixels must be spread out over the printer pixels. The scaling process creates interpolation artefacts such as periodic lines because of the accumulation of two adjacent columns/rows of pixels or white lines through destructive interference.

To avoid Moiré effects due to differences in resolution between the bitmap and you printer, add background colour to your page style with the Color button in the Area tab.

I don’t know what your “Leverarch” is but I guess it is some sort of binder and you want to watermark the position of the holes to punch them later. Here is the procedure for this watermark:

  • Design a small circle with the required diameter in Draw

  • Copy this vector shape and paste it in the header of any page controlled by your page style

  • Right-click on the circle image and Properties

  • In Type tab, keep it anchored To Paragraph

  • Still in Tab, use the Position parameters to put the image where you want it

    • Horizontal From left by xxx cm to Left page border
    • Vertical From top by yyy cm to Entire page

Repeat for the other holes.

To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!

In case you need clarification, edit your question (not an answer which is reserved for solutions) or comment the relevant answer.