Nicolaas Vroom

Light Dark Interference

Acryl and Oil on canvas
60 by 30 cm

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The above painting depicts a kind of light phenomenon that, as far as I can remember, I probably observed this in hotel "Austria am See" Sparkassegasse 1 in Gmunden Austria when I was about 13 years old in 1955.
I saw the light phenomenon in my hotel room when I woke up around 8 o'clock in the morning.
The painting consists of 3 parts:

The right part consists of an image with vertical lines. It represents a picture on a wall in my bedroom. Normally, if the light came from the sun, you would expect this to be a bright surface, but it was not. There were clearly vertical lines in the plane. This surprised me. How did that happen
Toen ik naar links keek zag ik dat het licht afkomstig was, door een spleet tussen de beide gordijnen bij het raam. Ik liep naar het gordijn en, dat herinner mij nog goed, toen ik vlak bij het gordijn kwam zag ik alleen hel zon licht en kon ik niks buiten zien.
Op het midden deel van schilderij staat de spleet ook die een egale gele kleur heeft.
Op het midden deel staat ook het gordijn. Voor zover ik mij het kan herinneren was het gordijn een helemaal zwart vlak. De verticale plooien op het schilderij, golven, zijn een vrije interpretatie van de kunstenaar. When I looked to my left I saw that the light was coming through a gap between the two curtains by the window. I walked to the curtain and, I remember it well, when I got close to the curtain I only saw bright sunlight and I couldn't see anything outside.
The middle part of the painting also shows the gap, which has an even yellow color.
The middle part also has the curtain. As far as I can remember, the curtain was a completely black area. The vertical folds in the painting, waves, are a free interpretation of the artist.
Then I opened the two curtains and looked outside. What I saw then is on the left part. It is a view of part of the lake, on which the hotel was located, from the window. The reader must understand that I was actually looking straight into the sun, not seeing the sun itself.
The view consists of 3 parts, 3 planes: The surface of the water. A smooth dark green hill on the other side of the lake and a smooth blue sky. That's all I remember.
However, there was something else and that seemed very important to me. On the surface I saw about 1000 points of light, 1000 glares, reflections of the sun's light. I think these bright spots are mainly caused by small waves on the surface of the water caused by the wind. By gusts of wind. I expect this must be part of the explanation why I saw lines in the picture against the wall.

Here ends the description of the natural phenomenon.
But not completely. I kept wondering how is this possible.
In high school I learned that you can get such an interference pattern by using your thumb and index finger. You then, as it were, make the letter O with your thumb and index finger, but just not that the two fingers touch each other, such that a very small gap remains. If you look out through that slit you will see the thin lines
For more detail about this subject look here: https://www.physicsforums.com/threads/lines-appear-when-staring-at-bright-lights-whats-the-explanation.288047/#:~:text=Hold%20two%20fingers%20about%2010,of%20dark%20and%20light%20lines.

Later at university I learned that there are so-called interference patterns. Such patterns are created when you drop two stones into the water at the same time. I think everyone has seen that when you drop a stone in the water, waves are created. These waves start where the stone touches the water and then expand outwards in circles. If you now use two stones, each stone causes a wave pattern of rings and where those rings touch each other you get an interference pattern.

But this is not the end of the story.
What I'm currently trying to find out is where exactly in Austria I saw the phenomenon, determine if you can still see it and take a photo of it. Secondly, to see whether the number of interference lines is always the same, whether the pattern of light glare from the reflection of the water has any influence and the position of the sun. This is important for the angle of reflection of the sun's light
I hope it works.

What makes the interference pattern on the wall so interesting is that it is so large.

For a technical discussion about interference patterns in general read this brilliant document by Frits Zernike:
https://www.science.org/doi/10.1126/science.121.3141.345 Original article
https://www.nobelprize.org/uploads/2018/06/zernike-lecture.pdf Full article. Please read the top part of page 240 carefully and inhale the joy of science.