Introduction

There is a huge chasm between knowing lighting tools and knowing them intimately. Regardless of the approach, it takes a long time and a lot of experience to get to the latter. There is a wide array of options on the market, so how do you know what to use and when? I have been shooting for some time now, and assisting those better than me for even longer. I have had the opportunity to work with a wide array of lights and lighting augmentation, but its only been a few items at a time, sometimes spread over many months (or years) before seeing them again. Many cinematographers have their go-to approach to bouncing and diffusing light by always keeping a small selection of materials in their kit. Oftentimes, these were chosen because of what’s available. Other times, we hear its good, so we use it. But unless you’ve had a lot of practice and seen the side-by-side effects of each, it can be hard to know what would work best in a given situation. Because of this, I decided to conduct an in-depth test of various diffusion and bounce materials centralized in one location in a controlled environment. Welcome to the Ultimate Diffusion and Bounce Test.

A little background. I am a documentary cinematographer who has to shoot a lot of interviews for my projects. Interview lighting can range from a simple, no-frills, one-light setup to a massive lighting package with hours of setup time. Regardless of the scale, you want the interview to look as good as it can. Just shining a light on someone doesn’t always produce the most flattering look. You generally need to soften the light by either diffusing it, bouncing it, or both. The decision of which to do, and what materials to use is the question. What look are you going for? Is you space limited? How much time do you have to set up? What’s your budget? All of these factors play into the decision – and having an answer to these questions is an important first step.

This test is designed to answer some of those questions. I must admit, this is primarily a selfish test to see what I like best. But it is also a test to give all cinematographers a resource to look at the same materials and decide for themselves what looks best to fits their needs. This test is by no means limited to documentary interview lighting. These tools are the same used for any lighting setup, whether you’re shooting a documentary, commercial, or feature film. Every material, whether diffusing or bouncing, augments the quality and output of the light source to produce a specific look and feel.

Test Sections

I have broken down the test into three sections: Diffusion Only, Bounce Only, and Bounce with added Diffusion. There are a wide array of materials on the market to fit these needs, but I have narrowed them down to the most widely used and available options.

Diffusion: Full Silk

1/4 Stop Silk

China Silk

Full Grid Cloth

1/2 (Lite) Grid Cloth

1/4 Grid Cloth

Frost

Opal (Lee 410)

1/2 White Diffusion (Lee 250)

Full White Diffusion (Lee 216)

Bleached Muslin (also tested as a bounce)

Unbleached Muslin (also tested as a bounce)

Bounce: White Griffolyn

Ultra Bounce

Bleached Muslin

Unbleached Muslin

Bead Board

Methodology

Bear with me, this test is exhaustive. I tried to include as much information as possible to give you a well-rounded and in-depth look at the materials. There is a lot in here, but I tried to break it down in as digestible of a manner as possible. Take what you need and the leave the rest for later.

To conduct a test like this, you first need to establish a set of guidelines that will allow for a consistent and equal comparison of materials. There are a few sets of criteria to consider: Consistency in the lighting instrument, the size of the light source, the distance of the source to the subject, and light pollution.



Lighting Instrument

For this test, I have chosen to use a K5600 Joker 400. Since we are shooting in a studio with no windows, the Joker 400 will give me an optimal exposure range to test with without having to slow down the light with scrims or ND filters in front of the lens. In the most extreme case, the Joker 400 flooded outputs 500 foot candles at a distance of 6′ from the subject. This is equivalent to an f/18 at ISO 800. As we add diffusion, bounce the light, or add diffusion to the bounce, there will be an adequate exposure that ranges between f/2.8 and f/18.

Size of the Source

In each of these test setups, the effective “light source” will vary. Sometimes it will be the Joker 400 when nothing is in front of it. Sometimes it will be the diffusion in front of the light, and sometimes it will be the diffusion in front of the bounce. See where I’m going with this? Ultimately, whatever is the “last line of defense” from the light to the subject is the “light source.” The larger the diffusion or bounce material is, the more it spreads the light. Because of this, I tried to keep the size of the various diffusion and bounce materials consistent, since the size of the “source” will have an effect on the spread, or softness, of the light. Nearly all of the materials are the same size, but there are a few outliers, due to physical restraints. All of the diffusion materials are 6’x6′, with the exception of the gels – Opal, 1/2 White Diffusion and Full White Diffusion. This is because it comes on a roll limited to 4′ in width, so I unrolled it to 4’x4′. All of the bounce materials are 6’x6′ with the exception of the bead board. Again, this is limited to a maximum of 4’x8′, so I again went with 4’x4′ to keep the shape consistent.







Distance of the Source to the Subject

Since I am selfishly doing this test to compare looks for an interview setup, I went with a distance that is most tailored to that for the size of the studio, the size of the diffusion / bounce, and the intensity of the light. But there is something very important to keep in mind with this – The Inverse Square Law. This law essentially states that if you double the distance between your light and your subject, you will reduce it’s intensity by 75%. Instead of being a constant reduction in light over distance, it is in fact and exponential change. What this effectively means is the light falloff is more dramatic the closer the light is to the subject. For example; If you setup a light close to two people standing in front of each other, the exposure on the person closer to the light will be significantly brighter than the person standing further away. But if you move the light further away, then the exposure difference from person to person will be reduced. The Inverse Square Law only holds true with a point of light, so the properties change as you bounce or diffuse light, but this is still very important to keep in mind when placing all of the instruments. We must keep a consistent set of distances between the light, the bounce, the diffusion and the subject so our values remain as constant as possible from test to test. You can see with the image to the left, at 6′, our subject is much brighter than the background. The falloff ratio closer to the light is far more pronounced. As the light moves further away to 10′, our subject and the background become more balanced in exposure because of the exponential change in light value. Ss the distance from the light to the subject becomes greater, the falloff becomes less dramatic. In our setup, the “light source” is always 6′ from the subject and the light itself is 4′ from the “source.” So in the Diffusion Only scenario, diffusion is 6′ from the subject and the Joker 400 is 4′ behind the diffusion. In the Bounce Only setup, the bounce is 6′ from the subject and the Joker 400 is 4′ in front of the bounce. Lastly, in the Bounce with added Diffusion scenario, the diffusion and the Joker 400 are 6′ from the subject and the bounce is 4′ from the light/diffusion. As we break down each testing section, you can see the lighting diagram illustrating these distances.



Light Pollution

This is the tricky part. It is challenging to do a scientific study on the particular aesthetic qualities of these materials, since some are designed to maximize the spread of the light, while others are designed to soften, yet restrict the spread. Light, in it’s nature, bounces around off any and all surfaces it comes in contact with. So if the diffusion material is designed to spread the light, then there is more light to interact with the environment than a diffusion designed to limit the spread. For the setup, we are working in a studio with the windows blacked out. There is no other source of light than the one we are testing. We have also not added any fill or negative fill that otherwise isn’t in the space, such as the floor, walls and ceiling. If we were working in a black box theater, the encompassing darkness would have an impact on the lighting by adding negative fill. Conversely, if we were working in a solid white studio, there would be a lot of natural fill from all directions. Our studio has a 12′ high white ceiling, wood floor, and a 25′ wide room with a brick wall and blackout material on the key side and partial white wall on the fill side. There is no one consistent tone in the room to overly influence the lighting one way or another. The only “flagging” of light we did was with barn doors to limit the spill of the Joker 400 to only hit the bounce or diffusion and not inadvertently spilling out to the wall or ceiling. Setup 5′ behind our subject is a grey seamless paper. This midtone color will help illustrate the light falloff, spread and intensity of the various materials without affecting the overall lighting of the subject. You can see this clearly as the grey card in the wide shot either blends in with the backdrop or is significantly brighter than the backdrop.







Metering

While just looking at the image produced with each material is incredibly helpful in deciding which to use, we also want to know what’s happening with the light. To do this, we will take two meter readings.





The first is with a color meter. In this test, we are working with a Minolta Color Meter IIIF. We will take a color reading of the Joker 400 by itself to determine a base color temperature, and then meter the light with the diffusion or bounce added. This will allow us to see if there’s any shift in color with the given material.





The second is with an incident light meter, in this case the Sekonic L-758 Cine meter. We will again take a base measurement of the intensity of the Joker 400 on its own from various positions, depending on the material being tested. We will then take a measurement with the diffusion or bounce added. This will allow us to see how much light is eaten up by the material.

These incident readings will be measured in footcandles (F.C.) so we know an intensity value regardless of the ISO or f-stop of the lens. To convert F.C. to a ratio understood by your camera, just remember this formula:

When shooting 24fps at 180° (1/48th sec) shutter – ISO 100 with 100 F.C. you will have an aperture of f/2.8.

You can then adjust as needed to reach your desired ISO or f-stop.

Since light is doubled or halved as you double/half the ISO or open or close one f-stop, this is an easy adjustment to make. If you double the ISO to 200, then you halve the F.C. (to 50) to achieve an f/2.8. If you stop down the lens one stop to f/4, then you would double the F.C. to 100. Make sense? Here is a chart to make it even easier.

f/1.4 f/2 f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22 ISO 25 100 200 400 800 1600 3200 6400 12800 25600 ISO 50 50 100 200 400 800 1600 3200 6400 12800 ISO 100 25 50 100 200 400 800 1600 3200 6400 ISO 200 13 25 50 100 200 400 800 1600 3200 ISO 400 6 13 25 50 100 200 400 800 1600 ISO 800 3 6 13 25 50 100 200 400 800 ISO 1600 2 3 6 13 25 50 100 200 400 ISO 3200 1 2 3 6 13 25 50 100 200 ISO 6400 .5 1 2 3 6 13 25 50 100

*24fps @ 180° Shutter

Working this way is great if you are on a location scout and don’t bring along a camera, or need to communicate light values without having to explain to your gaffer what ISO or f-stop will be on your camera. You can decide what ISO and f-stop are desirable for your shot and then know precisely how much light is required to reach proper exposure.



Camera





While this is a test about lighting, the camera plays a part as well. We are shooting this test with two Canon C300 MKII’s. The A Cam is shooting with a 35mm Rokinon Cine DS lens square on to the subject, 7′ away. The B Cam is shooting with an 85mm Rokinon Cine DS lens 7′ away at an angle into the fill side of the subject to see how the light wraps her face with the various diffusions and bounces. Both cameras are at ISO 800, white balance set to 6000°K (the temperature of the Joker 400), and shooting in Rec709. Why Rec709 and not Log? I don’t want to introduce any unnatural augmentation in contrast to the scene by color correcting. Since a 709 image is what we ultimately hope to achieve, I will start and end there with no correction in post.



Diffusion Only Test

In this setup, we are looking at the effects of putting various diffusion materials in front of our light source. These diffusions range from very faint that only affect the hardness of the shadow while maintaining the beam intensity, while others add a lot of overall softness and spread the light beam around. As with any real-life test, there are always minor fluctuations in the exposure and color temperature values. This can happen because of the ambient bounce in the room, the angle of the meter to the source, or the unmeasurable variations in how the materials interact with each other. I arrived at the “Approx. Light Loss & Color Temperature Change” by averaging the values across the entire test. As always, if you need to be precise in your values, conduct your own test in the environment you will be shooting in to take all of these factors into account.

Earlier, we discussed the need to have a consistent distance from the light source to the subject. We always want our “light source,” in this case the diffusion material, to be 6′ from our subject. We are also maintaining a 4′ distance from the light to the diffusion. Here is a diagram illustrating how we set up the test:





Full Silk The Full Silk, or “White Artificial Silk,” offers the most diffusion of the silks with a significant amount of ambient bounce.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -290°K (warming)

1/4 Stop Silk The 1/4 Stop Silk is a lightweight fabric offers a thin diffusion with a significant amount of ambient bounce.

Approx. Light Loss: 2/3 stop

Approx. Color Temperature Change: -220°K (warming)



China Silk The China Silk, or “Half Silk,” is a lightweight, slightly translucent natural silk fabric that offers medium diffusion with less ambient bounce than the artificial silks.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -230°K (warming)



Full Grid Cloth The Full Grid offers the most diffusion of the grids, but with much less ambient bounce than from the silks. The grid pattern in the cloth helps to focus the light, similar to an egg crate in a Chimera.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -340°K (warming)



1/2 (Lite) Grid Cloth The 1/2, or “Lite,” Grid offers slightly less diffusion than the Full Grid, while still controlling the ambient bounce.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -300°K (warming)



1/4 Grid Cloth The 1/4 Grid offers a thin diffusion, while controlling the ambient bounce.

Approx. Light Loss: 2/3 stop

Approx. Color Temperature Change: -210°K (warming)



Frost The Frost, or “Shower Curtain,” offers a light, soft glow with no ambient bounce. Since it is made of vinyl, the Frost holds it diffusion properties even when wet, making it a great choice for shooting outdoors.

Approx. Light Loss: 2/3 stop

Approx. Color Temperature Change: -490°K (warming)



Opal (Lee 410) Opal, or “410,” offers a very light diffusion that takes the edge off of shadows without affecting the overall shape of the light. It comes in roll form that allows for maximum flexibility in how it’s used.

Approx. Light Loss: 2/3 stop

Approx. Color Temperature Change: -240°K (warming)



1/2 White Diffusion (Lee 250) 1/2 White Diffusion, or “250,” offers a medium diffusion in roll form that allows for maximum flexibility in how it’s used.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -340°K (warming)



Full White Diffusion (Lee 216) Full White Diffusion, or “216,” offers a heavy diffusion in roll form that allows for maximum flexibility in how it’s used.

Approx. Light Loss: 1 stop

Approx. Color Temperature Change: -350°K (warming)



Bleached Muslin Bleached Muslin is a dense fabric that is primarily used to bounce light offering a soft, even glow with no hotspot. It can also used used as a very heavy diffusion.

Approx. Light Loss: 2 stops

Approx. Color Temperature Change: -440°K (warming)



Unbleached Muslin Unbleached Muslin offers the same properties as the Bleached Muslin, but with added warmth.

Approx. Light Loss: 2 stops

Approx. Color Temperature Change: -1420°K (warming)



Joker 400 @ 6' Joker 400 @ 10' Silk 1/4 Stop Silk China Silk Full Grid 1/2 (Lite) Grid Footcandles 500 200 84 140 80 84 90 F-Stop @ ISO 800 f/18 f/11 f/7 f/9 f/7 f/7 f/8 Light Loss (Stops) n/a n/a -1 1/3 -2/3 -1 1/3 -1 1/3 -1 Color Temperature 5950°K 5950°K 5940°K 5890°K 5830°K 5710°K 5690°K

1/4 Grid Cloth Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Bleached Muslin Unbleached Muslin Footcandles 110 110 150 110 80 45 45 F-Stop @ ISO 800 f/9 f/9 f/10 f/9 f/7 f/5.6 f/5.6 Light Loss (Stops) -2/3 -2/3 -1/3 -2/3 -1 1/3 -2 -2 Color Temperature 5730°K 5660°K 5810°K 5750°K 5690°K 5510°K 4530°K

Bounce Only Test

In this setup, we are looking at the quality of light produced from bouncing our light source into a material. In some instances, the quality of the bounce light is very similar to pushing a light through diffusion. In other instances, we are able to get a much softer light source. As with any real-life test, there are always minor fluctuations in the exposure and color temperature values. This can happen because of the ambient bounce in the room, the angle of the meter to the source, or the unmeasurable variations in how the materials interact with each other. The “Approx. Light Loss & Color Temperature Change” are averaged values from across the entire test.

Similar to the previous test, the bounce becomes our “light source” so we have positioned the bounce 6′ from the subject. But instead of pushing our light through the material, we are pushing it into the material. We have maintained the same distance of 4′ from the light to material, but this time in front. Here is a diagram illustrating how we set up the test:





White Griffolyn – Soft White Griffolyn is made of a tarp-like material that comes in various grades – soft, shiny or flat. It is a flexible bounce material for use in all kinds of environments.

Approx. Light Loss (compared to the Joker 400 at the same distance): 2 2/3 stops

Approx. Color Temperature Change: +150°K

Ultra Bounce Ultra Bounce offers two sides. The white front gives a soft, even bounce with no hot spot. The reverse black side side is a flat, non-reflective material good for negative fill.

Approx. Light Loss (compared to the Joker 400 at the same distance): 2 1/3 stops

Approx. Color Temperature Change: -200°K (warming)

Bleached Muslin Bleached Muslin is a dense fabric that is primarily used to bounce light offering a soft, even glow with no hotspot. It can also used used as a very heavy diffusion.

Approx. Light Loss (compared to the Joker 400 at the same distance): 2 1/3 stops

Approx. Color Temperature Change: +280°K (cooling)

Unbleached Muslin Unbleached Muslin offers the same properties as the Bleached Muslin, but with added warmth.

Approx. Light Loss (compared to the Joker 400 at the same distance): 2 2/3 stops

Approx. Color Temperature Change: -660°K (warming)

Bead Board Bead Board is a styrofoam material that offers a much softer bounce than say the Griffolyn. It can be cut into whatever size and shape required, making it a very flexible bounce material.

Approx. Light Loss (compared to the Joker 400 at the same distance): 2 1/3 stops

Approx. Color Temperature Change: -30°K (warming)

Joker 400 @ 6' White Griffolyn Ultra Bounce Bleached Muslin Unbleached Muslin Bead Board Footcandles 500 90 97 97 80 90 F-Stop @ ISO 800 f/18 f/8 f/8 f/8 f/7 f/8 Light Loss (Stops) - Compared to Joker 400 @ 6' n/a -2 1/3 -2 1/3 -2 1/3 -2 2/3 -2 1/3 Color Temperature 5950°K 6100°K 5800°K 6200°K 5430°K 6050°K

Bounce with Added Diffusion Test

Finally, in this test we are combining a bounce with added diffusion. This is typically called a “book light.” This setup can create some incredibly soft, pleasing, and natural light on your subject. With all the materials tested here, the sky’s the limit (as well as the strength of your light!) to how soft you want to go.

The positioning of all of the materials follows suit to our rules. Since the bounce is acting as the lighting instrument and the diffusion is the “source,” The bounce is 10′ from the subject and the diffusion is 6′ from the subject. The only difference with this setup and the Diffusion Only setup is the Joker 400 is placed at the same position as the diffusion to maintain a 4′ distance from lighting instrument to material. Below is a diagram of the test setup:

GRIFFOLYN





Silk 1/4 Stop Silk China Silk Full Grid 1/2 (Lite) Grid 1/4 Grid Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Footcandles 13 23 17 15 17 20 20 26 23 17 F-Stop @ ISO 800 f/2.8 f/4 f/3.2 f/3.2 f/3.2 f/3.6 f/3.6 f/4 f/4 f/3.2 Light Loss (Stops) -1 1/3 -1/3 -1 -1 -1 -2/3 -2/3 -1/3 -1/3 -1 Color Temperature 5600°K 5760°K 5780°K 5650°K 5700°K 5820°K 5440°K 5850°K 5790°K 5700°K

ULTRA BOUNCE





Silk 1/4 Stop Silk China Silk Grid 1/2 (Lite) Grid 1/4 Grid Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Footcandles 18 25 18 18 18 25 20 26 23 16 F-Stop @ ISO 800 f/3.6 f/4 f/3.6 f/3.6 f/3.6 f/4 f/3.6 f/4 f/4 f/3.2 Light Loss (Stops) -1 -2/3 -1 -1 -1 -2/3 -1 -2/3 -2/3 -1 1/3 Color Temperature 5400°K 5530°K 5560°K 5460°K 5530°K 5570°K 5450°K 5500°K 5450°K 5350°K

BLEACHED MUSLIN





Silk 1/4 Stop Silk China Silk Full Grid 1/2 (Lite) Grid 1/4 Grid Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Footcandles 18 23 20 18 18 23 23 26 15 21 F-Stop @ ISO 800 f/3.6 f/4 f/3.6 f/3.6 f/3.6 f/4 f/4 f/4 f/3.2 f/3.6 Light Loss (Stops) -1 -2/3 -1 -1 -1 -2/3 -2/3 -2/3 -1 1/3 -1 Color Temperature 5800°K 5970°K 6050°K 5880°K 5940°K 6070°K 5750°K 6030°K 5800°K 5980°K

UNBLEACHED MUSLIN

I unfortunately do not have a recorded example of diffusing the Unbleached Muslin with Frost. The F.C. and WB values in the chart are accurate though. I guess when shooting this many setups, one is destined to slip through cracks…







Silk 1/4 Stop Silk China Silk Full Grid 1/2 (Lite) Grid 1/4 Grid Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Footcandles 16 20 16 15 15 20 18 21 13 18 F-Stop @ ISO 800 f/3.2 f/3.6 f/3.2 f/3.2 f/3.2 f/3.6 f/3.6 f/3.6 f/2.8 f/3.6 Light Loss (Stops) -1 -2/3 -1 -1 -1 -2/3 -2/3 -2/3 -1 1/3 -2/3 Color Temperature 5160°K 5150°K 5100°K 5050°K 5090°K 5180°K 4830°K 5140°K 5000°K 5050°K

BEAD BOARD





Silk 1/4 Stop Silk China Silk Full Grid 1/2 (Lite) Grid 1/4 Grid Frost 410 Opal 250 1/2 White Diffusion 216 White Diffusion Footcandles 16 25 20 18 18 23 23 26 23 18 F-Stop @ ISO 800 f/3.2 f/4 f/3.6 f/3.6 f/3.6 f/4 f/4 f/4 f/4 f/3.6 Light Loss (Stops) -1 1/3 -2/3 -1 -1 -1 -2/3 -2/3 -2/3 -2/3 -1 Color Temperature 5730°K 5760°K 5680°K 5600°K 5630°K 5730°K 5330°K 5600°K 5530°K 5500°K

Conclusion

Conducting this test was incredibly helpful for me to see how all of these materials help shape the look and feel of the lighting. Each and every material, whether diffusing, bouncing, or a combination of the two, adds its own unique touch to the shape, softness and color of the light. Having this test as a reference will better inform my lighting decisions moving forward. My hope with this test was to not only learn something myself, but to make this material available to everyone to learn from. Cinematography is not a mystical power, but rather a skill that only gets better with practice and experience. I hope you all can take this information and apply it to your projects to see what works for you. The information presented here is only a starting point. You can play with using multiple layers in front of your light, or getting really soft with bouncing and multi-diffusing. The sky’s the limit!

Download a condensed PDF of this test here for future reference.

This test would not have been possible without the incredible support and dedication from the crew. A special THANK YOU to Scott Ruderman, Seth Macmillan, Jessie Adler and Shiri Paamony Eshel for dedicating your time and experience to this project and to Lindsey Sagrera for putting up with setup after setup after setup in the hot seat with grace.

Feel free to leave your comments below!