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
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
Type tab, keep it anchored To Paragraph
Tab, use the Position parameters to put the image where you want it
From left by xxx cm to
Left page border
From top by yyy cm to
Repeat for the other holes.
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