https://imgur.com/a/EJEp1P8
I understand that light acts as a wave and there is interference effects going on here but that’s about as far as my understanding goes. The situation confuses me even more considering there is only one light source.
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I don’t think this is due to anything like wave interference at all. Instead it is just a simple consequence of light diffusion.
Think about the light just as it comes passing through the holes in the grid. They don’t have perfectly sharp edges because it is scattered and diffused by the air. Even the shadowed areas have *some* amount of light falling on them as reflected from other areas of the room, otherwise they would be pitch black and you wouldn’t see anything at all in them.
The patches of light closest to the window are the smallest though so let us think of those as being 100% brightness. As we look farther away from the window the patches of light get larger and as a consequence dimmer at any given point; it is the same amount of light covering a larger area, so it is spread out and becomes less intense. Those patches of light are going to keep spreading out as they get more distant from the window and diffuse more, until the light patches are directly adjacent to each other. You can see this a little more than halfway through the pattern where it becomes an almost completely even patch of light with hardly any visible shadows.
As each patch of light keeps expanding eventually they start to overlap each other. The center of each patch then only has the light intensity left over from being scattered, say 35% of the intensity close to the window, but the patches of overlap combine the intensity from two adjacent holes and get up to 70% brightness! The brightest parts now are the areas between each patch of light, the areas which were previously in shadow.
I don’t think this is due to anything like wave interference at all. Instead it is just a simple consequence of light diffusion.
Think about the light just as it comes passing through the holes in the grid. They don’t have perfectly sharp edges because it is scattered and diffused by the air. Even the shadowed areas have *some* amount of light falling on them as reflected from other areas of the room, otherwise they would be pitch black and you wouldn’t see anything at all in them.
The patches of light closest to the window are the smallest though so let us think of those as being 100% brightness. As we look farther away from the window the patches of light get larger and as a consequence dimmer at any given point; it is the same amount of light covering a larger area, so it is spread out and becomes less intense. Those patches of light are going to keep spreading out as they get more distant from the window and diffuse more, until the light patches are directly adjacent to each other. You can see this a little more than halfway through the pattern where it becomes an almost completely even patch of light with hardly any visible shadows.
As each patch of light keeps expanding eventually they start to overlap each other. The center of each patch then only has the light intensity left over from being scattered, say 35% of the intensity close to the window, but the patches of overlap combine the intensity from two adjacent holes and get up to 70% brightness! The brightest parts now are the areas between each patch of light, the areas which were previously in shadow.
I don’t think this is due to anything like wave interference at all. Instead it is just a simple consequence of light diffusion.
Think about the light just as it comes passing through the holes in the grid. They don’t have perfectly sharp edges because it is scattered and diffused by the air. Even the shadowed areas have *some* amount of light falling on them as reflected from other areas of the room, otherwise they would be pitch black and you wouldn’t see anything at all in them.
The patches of light closest to the window are the smallest though so let us think of those as being 100% brightness. As we look farther away from the window the patches of light get larger and as a consequence dimmer at any given point; it is the same amount of light covering a larger area, so it is spread out and becomes less intense. Those patches of light are going to keep spreading out as they get more distant from the window and diffuse more, until the light patches are directly adjacent to each other. You can see this a little more than halfway through the pattern where it becomes an almost completely even patch of light with hardly any visible shadows.
As each patch of light keeps expanding eventually they start to overlap each other. The center of each patch then only has the light intensity left over from being scattered, say 35% of the intensity close to the window, but the patches of overlap combine the intensity from two adjacent holes and get up to 70% brightness! The brightest parts now are the areas between each patch of light, the areas which were previously in shadow.
This one isn’t diffraction. The light source isn’t a single point, when you get far enough away the sun’s size gets bigger than the size of a single hole, so how light or dark a point on the ground is depends on how the sun is revealed by multiple different holes.
Lets say you’re way up close on a hole, the sun fits easily within it, you keep the sun centered within it. As you back up the edges of the hole block the outer ring of the sun, so you get less light. As you back up farther, the sun spills into the neighboring holes, so the ring of blocked light is a smaller proportion of the whole sun. The opposite happens for the web between the holes, up close 100% of the sun is occluded, but then as you get farther the holes next to it start to let light through.
This one isn’t diffraction. The light source isn’t a single point, when you get far enough away the sun’s size gets bigger than the size of a single hole, so how light or dark a point on the ground is depends on how the sun is revealed by multiple different holes.
Lets say you’re way up close on a hole, the sun fits easily within it, you keep the sun centered within it. As you back up the edges of the hole block the outer ring of the sun, so you get less light. As you back up farther, the sun spills into the neighboring holes, so the ring of blocked light is a smaller proportion of the whole sun. The opposite happens for the web between the holes, up close 100% of the sun is occluded, but then as you get farther the holes next to it start to let light through.
This one isn’t diffraction. The light source isn’t a single point, when you get far enough away the sun’s size gets bigger than the size of a single hole, so how light or dark a point on the ground is depends on how the sun is revealed by multiple different holes.
Lets say you’re way up close on a hole, the sun fits easily within it, you keep the sun centered within it. As you back up the edges of the hole block the outer ring of the sun, so you get less light. As you back up farther, the sun spills into the neighboring holes, so the ring of blocked light is a smaller proportion of the whole sun. The opposite happens for the web between the holes, up close 100% of the sun is occluded, but then as you get farther the holes next to it start to let light through.
What a nice video!
The phenomenon is well-known in the context of the [Siemens star](https://en.wikipedia.org/wiki/Siemens_star):
> Under optical blur from defocus, a Siemens star (like any periodic pattern) gives rise to the phenomenon of spurious resolution above the resolution limit, i.e. toward the center of the Siemens star. (Spurious resolution appears similar to aliasing, but it is a purely optical phenomenon, so it occurs without need of pixels.) This results in inverted polarity of the stripe pattern: **black stripes appear in the place of white stripes and vice versa** (and further polarity inversions occur further inward).
Here it’s not the resolution of the camera but the sharpness of the shadows.
> I understand that light acts as a wave and there is interference effects going on here
So definitely not light wave interference but “pattern interference”, if I may coin that expression.
What a nice video!
The phenomenon is well-known in the context of the [Siemens star](https://en.wikipedia.org/wiki/Siemens_star):
> Under optical blur from defocus, a Siemens star (like any periodic pattern) gives rise to the phenomenon of spurious resolution above the resolution limit, i.e. toward the center of the Siemens star. (Spurious resolution appears similar to aliasing, but it is a purely optical phenomenon, so it occurs without need of pixels.) This results in inverted polarity of the stripe pattern: **black stripes appear in the place of white stripes and vice versa** (and further polarity inversions occur further inward).
Here it’s not the resolution of the camera but the sharpness of the shadows.
> I understand that light acts as a wave and there is interference effects going on here
So definitely not light wave interference but “pattern interference”, if I may coin that expression.
What a nice video!
The phenomenon is well-known in the context of the [Siemens star](https://en.wikipedia.org/wiki/Siemens_star):
> Under optical blur from defocus, a Siemens star (like any periodic pattern) gives rise to the phenomenon of spurious resolution above the resolution limit, i.e. toward the center of the Siemens star. (Spurious resolution appears similar to aliasing, but it is a purely optical phenomenon, so it occurs without need of pixels.) This results in inverted polarity of the stripe pattern: **black stripes appear in the place of white stripes and vice versa** (and further polarity inversions occur further inward).
Here it’s not the resolution of the camera but the sharpness of the shadows.
> I understand that light acts as a wave and there is interference effects going on here
So definitely not light wave interference but “pattern interference”, if I may coin that expression.
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