Watermarks blurred on resized export

[zisoft (Mario Zimmermann)]

Just using darktable for a few weeks now and I’m really blown away by this piece of software!

I always document my woodworking projects with lots of photos. To put them on my website I usually resize them to 1200 pixels longest border. For this I have created an export preset and this works really well.

Now I noticed that watermarks get heavily blurred when the image is resized during export.

I use my own watermark here but to keep things simple I have demonstrated that with the standard darktable watermark.

The first image is in full resolution:

The second image is exported with a resize to 1200 pixels and shows the blurred watermark:

My workaround now is to export the images in full resolution and resize them down to 1200 with other software (the simple preview app on a Mac does the job pretty well). The third image shows the result.

I have played around with the export settings (high quality resampling) but that does not make any noticeable difference.

Is this a bug in the export module or am I simply missing a necessary step here?

Thanks in advance for any hints.

[Claes]

Moinchen, @zisoft,

I wonder if this might be a MacPhenomenon?

I performed the same operations as you did,
but on a Linux machine, and here is the result:

Have fun!
Claes in Lund, Schweden

[zisoft (Mario Zimmermann)]

Hi @Claes,

Is this your result with export resize to 1200?

thats how I want it to be

[Claes]

Correct. The big “background” == original size (6500 something).
The small rectangle at right = exported and resized in darktable to 1200.

[zisoft (Mario Zimmermann)]

I tried several settings, unfortunately all with the same result: The watermark gets heavily blurred on export with resize.

Can anyone else running darktable on MacOS please try and confirm?

[chris]

Is there a difference with and without high quality resampling in the export module?

[zisoft (Mario Zimmermann)]

No noticeable difference with high quality resampling, still blurred.