Stained Glass Projection

A couple of months ago I was enjoying the interior of St John’s Cathedral here in Brisbane. In particular in this capture, it was the image of the stained glass projected by the sun onto the column that caught my eye.

My take after many attempts at preserving shadows as well as highlights in a pleasing way.
2022-03-21_09-20-18.30_DSC6948.NEF (19.4 MB)

This file is licensed Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA).


great, church windows always are challenging…

here my attempt in RT 5.8-dev. My aim was to keep the windows in the background colorful and the structure of the stone visible.

2022-03-21_09-20-18.30_DSC6948.NEF.jpg.out.pp3 (15,0 KB)

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A great photograph.
Because of the enormous contrast, I created three exposures -2, 0 and +1 EV via Filmulator. These were blended using Enfuse. In GIMP I used my equal luminosity mask plug-in to make slight changes in the darkest and lightest parts.


G’day, mate!

Great shot!
I wanted to see if I could put more emphasis on the projection
onto the column. Sort of worked for me – I am certain that other
forumers are more skilled than I in the noble art of killing blown

Have fun!
Claes in Lund, Sweden

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A little off-topic.
Why in Davinci Resolve I don’t need to do any “highlight reconstruction” actions after demosaic, but in darktable I need to activate this option to avoid color abnormalities?

Davinci does it for you automatically most likely, akin to other photo editing software. Darktable is all about giving users control and power to let them do what they want to do, and not work around presets and per-configured norms the developers decide for you.

I struggled to reconstruct the highlights in a pleasing manner, so I took the easy way out :slight_smile: Focusing instead on the contrast between the illuminated foreground and the darker background.

2022-03-21_09-20-18.30_DSC6948.NEF.xmp (13.7 KB)



If I look at the histogram, of the RAW and not the edited version, in RawTherapee I see that both the green and blue channels are actually clipped:

There are more clipped areas shown (pink indicator, hard white in reality), I just highlighted the most obvious one. Those hard, white spots are very hard to turn into a pleasing area (for Davinci and other editors alike), especially on an image like this where it is in the middle of the subtle coloured lights.

Davinci Resolve, like so many other proprietary editors will do stuff under the hood that the user isn’t aware of and you might not be able to influence. RawTherapee, darktable and other editors will give you all the freedom to try and tackle this.

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2022-03-21_09-20-18.30_DSC6948.NEF.arp (13.1 KB)


Oops! In my previous version I forgot to apply highlight recovery in Filmulator. Similar process to last time, but blends of -1, 0, and +1.


Actually, in darktable, all of the colour channels are somewhat clipped in the projected light area. fortunately, the strong differences in the colours of the glass means that there is enough information at each part of the image of the window for highlight reconstruction to work its magic. WIthout the highlight construction, darktable gives me large swathes of the faux pink as a result of clipping.

The extreme of the projected brightness versus the dark interior shadows is what makes this such a challenge. I “cheated” somewhat by using the tone equalizer to a fairly large degree (at least, I consider it an unusually large degree).


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RTdev commit feada4cd0
2022-03-21_09-20-18.30_DSC6948.jpg.out.pp3 (14.2 KB)


To my knowledge darktable doesn’t have the ability to show the histogram of a RAW image, which makes it hard to determine if one or more channels are clipped or not.

If I look at the “normal” histogram in RawTherapee I do see a mini spike in the red as well. This does however depends on the input colour profile that is chosen. If I choose Camera standard, the default for this camera in RT, I see this mini spike, but if I choose the DCP profile that matches both the camera and the used picture control (i.e.: Nikon D3300 Neutral) I do not see this spike, only the blue and green one.

About the clipped areas and looking at your edit: Highlight reconstruction only does a rather average job here, especially the blown spot on the bottom of the pillar, but this noticeable discolouration and artefacting can also be seen in other areas. This is not darktable specific and limited to your edit, though, the other edits all have an obvious hard time creating a pleasant colour transition, tackling artefacts and/or disguising the blown areas.

“Technically,” you’re right. But that’s clear. ok.

It’s just how I didn’t twist this highlight reconstruction, and still it turned out to be a trehsold. It’'s possible to make masks, of course. But I don’t think they were somehow made proprietary during development.
I know what you mean. But the color highlights in the lights in dt are stronger than the lights in Resolve. Such highlights are only whitewashed with a bolder stroke. Tried different variations of working with highlight reconstruction. Most likely, you need to try more classic tools.
Okay - I’m interested in that. But it’s the technical part that interests every user, and this is more of a technical point than an aesthetic one.
I guess that’s the difference between closed and open source/.
The user, if working with opensource, is obliged to understand the technical aspects, whereas he could work more productively just on the moment of what he knows.
But this is already a philosophy. I understand that this is not anyone’s …
Yes, it’s off-topic. Closed.

My try, thanks for posting!

2022-03-21_09-20-18.30_DSC6948.NEF.xmp (11.3 KB)


Anyway i prefer white than extreme recoveries that are so ugly and unnatural… :slightly_smiling_face:

I love churches; light, colors, compositional elements. Although, the Sagrada Família in Barcelona drove me nuts… :crazy_face:

In rawproc, librtprocess highlight reconstruction, no tone curve other than the TRC in the output color profile:

Been to Brisbane twice, second trip was two weeks working at Boeing House, quite sad I didn’t get to this gem…


Are you referring to my off-topic? :slight_smile:

Not at all.
I mean that most of the time no extreme recovery leads to a pleasant result.
Either leave burnt parts white or expose them properly :slightly_smiling_face:

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Ah, well, in theory, yes))