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Why is moonlight a hard light?


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#1 Joe Lotuaco

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Posted 08 October 2007 - 05:58 PM

I'm a little confused as to why moonlight is a hard light. Theoretically the moon is just a big bounce and it's also a very very distance source. When you move a light source further away and bounce it, it becomes soft right? But when I look at moonlight on a clear night with a full moon out, there are obviously hard shadows which I assume are because the distance between what's being lit and what is creating the shadow is relatively close. So is the light quality really hard or is it just perceived to be a hard light because of the relation of objects casting the shadows to the subject being lit?

While we're on the topic of moonlight, what are some "recipes" for convincing moonlight? I've heard of people adding some plus green to a mixture of blue.
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#2 Richard Andrewski

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Posted 08 October 2007 - 06:14 PM

Considering that the moon is on average about 238,000 miles from the earth, it isn't considered to be a (relatively) big bounce source. Not like a foam core in the same room with a subject being lit. Therefore, that's why moonlight qualifies as a hard light. It's basically a point light source because it's relatively small, bright and against a black void. Just like the sun although not nearly as bright.
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#3 Michael Nash

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Posted 08 October 2007 - 06:16 PM

Theoretically the moon is just a big bounce and it's also a very very distance source.


1/2 a degree is a pretty small source! The moon is big, and the sun is hugely bigger -- yet the sun is a hard source at our distance.

We've discussed moonlight quite a bit recently, so try a search. Moonlight is sunlight reflected off a gray surface, so it's theoretically 5600 degrees K and photographs like daylight. In real life we see it as a pale blue in part because of the way our eyes see color in very dim lighting.

Everyone has their own favorite recipe for moonlight, and it depends on the "look" you're going for. What works for one movie might be totally wrong for another.

Common practice is to use a light source that's 1/2 blue (4300 degrees K), and underexposed quite a bit. Some people like to add White Flame Green to the lights because it really cancels out red wavelengths in a way that's similar to what we see with our eyes in real moonlight. To me the resultant color is too green to appear naturalistic on its own, but with post correction looks very convincing.

I don't like using PlusGreen for moonlight because it has so much yellow in its spectrum that it "warms" the moonlight back up too much. A green that's more toward cyan does a better job, IMO.
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#4 David Mullen ASC

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Posted 08 October 2007 - 06:54 PM

Since the size of the moon in the sky, by coincidence, is more or less the same as the size of the sun in the sky, hence why we have solar eclipses, they are more or less the same size source and thus moonlight is a fairly sharp light source.

Of course, on a hazy night with light cloud cover, it can be softened just like sunlight can be.

I think one reason we percieve moonlight as softer is that at such low light levels, our irises are so wide-open that we can't really focus sharply, almost like a bad Zeiss Super-Speed wide-open.

On a clear night with a full moon, look at the shadows of trees on the ground, or your own shadow -- it's a sharp pattern.
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#5 Stephen Whitehead

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Posted 13 October 2007 - 11:40 PM

1/2 a degree is a pretty small source!


That statement perked my interest. Now clearly a light's softness is determined by its relative size to the subject it is lighting, but I have never known DP's to actually measure softness in terms of degrees. What did you have in mind when you said this? How is the 'degree' of a soft light calculated? Is it sort of like drawing a triangle between the subject and the size of the soft source?

Cheers,

Steve

Edited by Stephen Whitehead, 13 October 2007 - 11:42 PM.

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#6 Michael Nash

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Posted 14 October 2007 - 12:39 AM

That statement perked my interest. Now clearly a light's softness is determined by its relative size to the subject it is lighting, but I have never known DP's to actually measure softness in terms of degrees. What did you have in mind when you said this? How is the 'degree' of a soft light calculated? Is it sort of like drawing a triangle between the subject and the size of the soft source?


I don't know about using degrees to describe the softness of light; I was just pointing out that a full moon measures about 1/2 degree when viewed from the Earth. I don't see how anyone could consider that a soft source!
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#7 Walter Graff

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Posted 14 October 2007 - 09:42 AM

The problem is you are looking at the moon and not what it does, sort of the equivalent of looking at a light and not at what light it casts. You are in a way saying the moon is a big reflector so should act like one, yet not considering that it is also a small object in the sky so at that distance and size is really more of a flashlight than a fluorescent tube. To see it, you have to do what I did on a full moon lit night this summer. I sat outside for about an hour in complete darkness. And I waited for my eyes to adjust. And what did I see? I saw that moon light was clearly blue looking. I know that not by looking at it directly but at what it does to the outdoors at night and how it does it with no other color reference. It created a sharp light that cast clear but very dim shadows. Funny thing is our entire notion of blue light is completely incorrect but formed not because of how light really is but how we perceive light in dimly lit situations. Did you ever walk outside of a building on a bright day to notice that everything looks blue? Now imagine that and decrease the intensity 150,000 times or the difference in intensity of the moon compared to the sun. And there you have what moon light is. Well, almost is. Actually the moon is far redder/brownish than it appears to your eye. Due to something called the The Purkinje effect, your eyes tend to generalize shades of color in dimly lit situations and the rods in your eyes force you to see what is more yellow/red in quality levels of light as blueish-green so turn the true reddish brown shades of the moon to grey. In color temperature terms, the moon is really more like 4100 kelvin. Which begs the question, what color do I use to make moon light? And that is totally subjective. Depending on subject matter and my mood, I do everything from half CTBs to theatrical blue gels. There is no wrong or right, just what works for you at the time you are doing it based on the scene you are lighting.

And just for fun if you want to see the true shades of the moons surface you can try this photographic trick that enhances the real colors of the moon. I wish it looked like this every day.
http://www.colormoon.pt.to/


Funny how my degree in astrophysics comes into play with this field of film and video all the time. :)


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#8 Mark Dunn

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Posted 14 October 2007 - 03:09 PM

That statement perked my interest. Now clearly a light's softness is determined by its relative size to the subject it is lighting, but I have never known DP's to actually measure softness in terms of degrees. What did you have in mind when you said this? How is the 'degree' of a soft light calculated? Is it sort of like drawing a triangle between the subject and the size of the soft source?

Cheers,

Steve


Half a degree of arc. The '90 in a right angle' sort of degree, not the 'it's all a matter of degree' sort.
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#9 Walter Graff

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Posted 14 October 2007 - 06:48 PM

Half a degree of arc. The '90 in a right angle' sort of degree, not the 'it's all a matter of degree' sort.


All he is saying is that the moon is a very small pinpoint of light in the nights sky so while it is big, it's more like a fresnel than a reflector.



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"Scientists who dissent from the alarmism have seen their funds disappear, their work derided, and themselves labeled as industry stooges. Consequently, lies about climate change gain credence even when they fly in the face of the science."

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#10 Stephen Whitehead

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Posted 14 October 2007 - 10:47 PM

No I understood what he was saying. but what I mean is that if you were to draw an isoslies triagle from the subject to the edge of a source, you could theorhetically determine its softness based on degrees. for example a 4x4 frame with grid cloth at say 6 or seven feet might give the same softness as a 12x12 frame from oh say 20 feet (That math is not correct). now obviously you'd need more light going through the 12' frame to get the same exposure, but the softness would be the same... providing you did the math.

steve
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#11 Walter Graff

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Posted 14 October 2007 - 10:53 PM

No I understood what he was saying. but what I mean is that if you were to draw an isoslies triagle from the subject to the edge of a source, you could theorhetically determine its softness based on degrees. for example a 4x4 frame with grid cloth at say 6 or seven feet might give the same softness as a 12x12 frame from oh say 20 feet (That math is not correct). now obviously you'd need more light going through the 12' frame to get the same exposure, but the softness would be the same... providing you did the math.

steve



You could determine intensity by distance but softness is a perception and would not work that way. ANd when you are toalking about moon distances and moon composition, your theory goes out of the water.
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#12 Hal Smith

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Posted 14 October 2007 - 11:29 PM

You could determine intensity by distance but softness is a perception and would not work that way. ANd when you are toalking about moon distances and moon composition, your theory goes out of the water.

For one thing, falloff would be totally different in his two examples. Wraparound wouldn't "wrap" as much with the source up close. The angles would be the same but the intensity would decrease faster with distance giving a more contrasty look to the wrap.

Which is why ultimately it ain't the Physics that counts but a good eye and a lot of experience.
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#13 Walter Graff

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Posted 15 October 2007 - 12:03 AM

For one thing, falloff would be totally different in his two examples. Wraparound wouldn't "wrap" as much with the source up close. The angles would be the same but the intensity would decrease faster with distance giving a more contrasty look to the wrap.

Which is why ultimately it ain't the Physics that counts but a good eye and a lot of experience.



Hence why I use the term perception. Fact is, how we perceive the moon is actually more false perception than reality. Moonlight is not 'white' and it's effect is not 'blue'. Our eyes trick us. The moon is the same size on the horizon as it is at its apex. Our eyes trick us. etc... How you create the moon in whatever you create it in is more about the context of what you are making than how you make it by itself. How you make it often gets lost to a story. But without a good eye and a talent to enhance reality (aka lighting a scene), your just a schlep, but even then most folks will never know the difference. You'll find ten guys who all have ten ways of making moonlight, none wrong, just different as moonlight is one of the most subjective effects you can make. And depending on the setting that moonlight could be hard or soft, blue or white/blue. Whether you make it hard light or soft light is not really the question. Some folks make it both ways depending on how they perceive it and what the scene calls for. In fact I'd go as far to say that I have recently seen moonlight represented as softer than harder and it worked just as well to me. Even do it myself quite often. An example in the differences is often seen in exterior wooded night scenes were light is represented with hard beams in wider shots but seen in close ups as soft reflections on faces. I just lit a wooded chase scene where I did just that. In this case harder light on the close ups (which I started with) seemed like too theatrical than reality (like Burtons Sleepy Hollow) so I switched to soft glows. Left hard light as soft focus in background on close ups. Worked great. Looked natural. Not right or wrong, just how I felt it needed to be lit for that shot. Could feel completely different depending on an entirely different setting.

Walter Graff

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"Scientists who dissent from the alarmism have seen their funds disappear, their work derided, and themselves labeled as industry stooges. Consequently, lies about climate change gain credence even when they fly in the face of the science."

- Richard Lindzen ,Professor of Atmospheric Science/ MIT
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#14 Jonathan Bowerbank

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Posted 15 October 2007 - 12:51 AM

It doesn't necessarily HAVE to be a hard light. I'm constantly reminded of Rousselat's work ("Sleepyhollow", "Big Fish", "Interview with the Vampire", etc.). He usually keeps his moonlight incredibly soft and not necessarily only as a hard backlight as most people tend to do.

Recreating moonlight on film is never going to appear realistic, but it's always possible to capture the aesthetic feel and look of moonlight as we would like to have it in a more romantic and fantastic world such as film.
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#15 gregory mandry

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Posted 15 October 2007 - 06:00 AM

In low light your eyes don't see colour but for that matter go out on a cloudy night in the woods and you really are hard put to see anything. So lighting for night is more about obeying conventions.

These conventions used in films and TV enable us to pretend it's night yet still see. eg the moonlight is blue... (especially in Hollywood) etc.

The big problem with lighting for night (having tried it a few times) is the amount you have to light. if you put your subject in the woods with no other source but the moon and you just light the subject with a large HMI then you are not lighting the woods. so you end up having to light all the background and foreground.

I always find if you are on a tight budget and you want a convincing look, try and squeeze some practicals in. They are great for motivating light and then you can use your blue moon convention as a fill for close ups.

just a thought.
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#16 Felipe Perez-Burchard

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Posted 16 October 2007 - 05:04 AM

I'm constantly reminded of Rousselat's work ("Sleepyhollow", "Big Fish", "Interview with the Vampire", etc.). He usually keeps his moonlight incredibly soft and not necessarily only as a hard backlight as most people tend to do.


just a quick correction that Sleepy Hollow was shot by Emmanuel Lubezki, but also Super Soft like you say, and like Phillipe Rousselout's work you mention...

;)
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