"Fill holes" change the color of the image

[Christoforos Vasilakis]

Hi,

The “Fill holes” feature in “Panorama Editor” seams to affect the color of the image close to the filling area. For example, look at the top of the mountain (pointed by the arrow) in the following images. Using the “Fill holes” feature the top of the mountain is darker. On the other hand, without using the “Fill holes” feature the top of the mountain is brighter. Is there a way to avoid this color changing effect close to the filling area?

Kind regards,

Christopher

[John Houghton]

Christopher,  I had a go at reproducing this and did not get the colour changing effect.  Then I noticed you had tone mapping enabled.  So I tried again and applied some generous tone mapping adjustments before applying the fill holes option.  I then did get some colour changes similar to what you found.  Could that be at least a part of the explanation for what you are seeing?   Perhaps you could try generating a tiff file with the tone mapping you want.  Then input that to a new project and do a fill holes (without tone mapping enabled, of course) and see if that avoids the problem.

John

[John Houghton]

Or are the colour changes simply a consequence of zero overlap blending?

John

[Christoforos Vasilakis]

Hi John,

Thank you for your response. The screenshots I shared are from an HDR panorama. I can provide the raw files (approximately 1.9 GB) if needed.

In my tests, the color change occurs even without applying aggressive tone mapping adjustments—though I confirm that if "Tone Mapping" is completely disabled, the color change does not happen. Since tone mapping is important for my workflow, I would prefer to keep it enabled.

Regarding the "Zero Overlap" blending method, I’m not an expert, but based on its description, I suspect the algorithm’s steps might influence the panorama images. If the fill color is calculated first and then the zero overlap algorithm is applied at the seams, this could affect areas near the fill region—especially if the fill colors differ from the actual image content

From my understanding, since there is “no real content” (i.e., transparent pixels) above the panorama images, the filling process ideally shouldn’t alter the actual image content.

For now, I’m manually patching the small gaps, but having "Fill holes" work without impacting image colors would be very helpful when faster edits are needed.

Kind regards,
Christopher

[PTGui Support]

Hi Christopher,

The color change is caused the tone mapping, not by Fill Holes or by the
blender.

When tone mapping an image, the brightness of a pixel is influenced by
the surrounding pixels. In the first case there are no surrounding
pixels; once you enable Fill Holes, there are surrounding pixels.

PTGui applies Fill Holes before tone mapping, because it is part of the
blending process (which also must be done before tone mapping).

What you could try is to export the tone mapped panorama without Fill
Holes. Then load it into PTGui as a source image in a new project and
enable Fill Holes. Be sure to use TIFF for the intermediate export, jpg
does not support transparency.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com

On 8/25/25 00:55, Christoforos Vasilakis wrote:
> Hi John,
>
> Thank you for your response. The screenshots I shared are from an HDR
> panorama. I can provide the raw files (approximately 1.9 GB) if needed.
>
> In my tests, the color change occurs even without applying aggressive
> tone mapping adjustments—though I confirm that if "Tone Mapping" is
> completely disabled, the color change does not happen. Since tone
> mapping is important for my workflow, I would prefer to keep it enabled.
>

> Regarding the "Zero Overlap*"* blending method, I’m not an expert, but

> based on its description, I suspect the algorithm’s steps might
> influence the panorama images. If the fill color is calculated first and
> then the zero overlap algorithm is applied at the seams, this could
> affect areas near the fill region—especially if the fill colors differ
> from the actual image content
>
> From my understanding, since there is “no real content” (i.e.,
> transparent pixels) above the panorama images, the filling process
> ideally shouldn’t alter the actual image content.
>

> For now, I’m manually patching the small gaps, but having "Fill holes*"*

> 1.png
>
> 3.png
>
> Kind regards,
>
> Christopher
>
>
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[Christoforos Vasilakis]

Thanks for the answer!