Using a Scrim Net to Control Background Brightness

One of the best ways to achieve a nice soft light on your subjects is to use a scrim. These scrims can range from large reflectors to giant sheets, but they all perform the same task, and that’s diffusing hard light. The problem with scrims is that while diffusing the light, they also lower the power of that light. This loss in power is dependent on the specific scrim you are using and can range from a quarter stop of light all the way to one and a quarter stop of light. The problem with this is that as you lower the light on your subject, while still getting a proper exposure on them, you are in turn raising the exposure of your background. In this video you can see how Joel Grimes uses a scrim net to help control this added brightness to his background.

When lighting a subject, it’s common for a photographer to want to have the background slightly darker than the light on his subject. When using a scrim as a light diffuser, this is an inherently hard task to complete. In the example from the video, Grimes is using a one stop silk to diffuse the light on his subject. While keeping a correct exposure on his subject, this makes the background one stop brighter.

Bright background with no scrim net

In order to combat this effect, Grimes adds a two stop scrim net behind his subject. Now with minus one stop on his subject and minus 2 stops on his background, the background now has an effective minus one stop when maintaining a correct exposure on the subject.

Darker background with scrim net

As mentioned in the video, the main issue when using this technique is the possibility of the net showing up in your image. By using a shallow depth of field, any detail in the net is blurred away and unnoticeable.

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22 Comments

Jeroen Lucas's picture

Nice tip.. But i personally like the background with no scrim net more.

Adam T's picture

I've always used nd's with a skrim.

Jason Vinson's picture

How does using an ND help when using a scrim?

Adam T's picture

The scrim is to neutralize the shadows on the subject and the ND is to properly level out the background. Also using v-flats and reflectors will give the subject a boost if needed.

Steve Franklin's picture

'properly level out the background'? I don't get it.

ND reduce the light by a determined factor - no more, no less.

What am I missing here?

Hans Rosemond's picture

Maybe he's speaking of balancing flash with ambient? Not sure.

Sergio Miranda's picture

I think he's calling the black net an ND.

Adam T's picture

The flash or the reflector is to boost the subject, the nd filters are to pull the background out much like the net would but with out the setup.
Yes ND's lower the light, so the easiest way to shoot a subject with faster apertures is to reduce the light and add a kicker.

http://static.bhphoto.com/images/images500x500/1458252257000_853602.jpg

Jason Vinson's picture

ah ok, that's where the confusion is. The scrim on the subject doesn't add light, it lowers the light, which is why the background gets brighter when using it and why they add the scrim net. Also, an ND will never allow you to get a darker background without also darkening your subject. In your example of using flash on your subject, the ND will lower the light on the background while simultaneously lowering the amount of light from your flash. ND filters will always lower the light on everything in your frame no matter what type of light you use. Whereas the scrim net allows you to lower the light selectively in a similar way to using flash to underexpose the background. The only difference is that the scrim net allows you to lower the background light while using natural light.

Adam T's picture

Well the blown out BG will always happen with or without the scrim. The scrim add softer shadows to the subject.
Yes the ND will low the total value of light and that why a kicker of some sort needs to be on the subject.
Think of it like this, expose and neutralize the BG and then light the subject.

The nets are good but can also give you a huge chance in seeing it. If your not tethered or don't have a big screen to check you shouldn't really use a net.

Lane Shurtleff's picture

DIY idea. I've been using these 10x12 black net tarps from Harbor Freight here in the US for years. Very strong with brass eyelets every foot along all the sides. This one I'm linking to is about 1.6 stops light loss.
You can stretch it over any type of metal pipe framework ( I personally use Matthews) but stay away from plastic tubing. In any type of wind or gust, if it's not anchored down VERY securely it will fly away.
http://www.harborfreight.com/10-ft-x-12-ft-mesh-all-purposeweather-resis...

Deleted Account's picture

Thank you for the public service message.

Any technique that balances the background and foreground ratios is most appreciated. There is an epidemic of hack photographers out there that let all of their backgrounds blow like an H bomb. Of course, they will usually say it looks cool. But really, most of them do not actually know how to shoot it any other way. For the record, there are just as many professional photographers guilty of this as amateurs.

Justin Haugen's picture

It's rampant because it's the most accessible way to do it, unfortunately.

Steve Franklin's picture

I guess because this requires a lot more effort and most photographers aren't in the business of dragging a trailer to get the image they want.

For my money I'd shoot with a scrim but then just shoot the background separately (he had a tripod) and mask it if it were that important. Not that you'd even have to do that with only a 1.5 stop difference on a camera with a 14 stop dynamic range.

Sounds like a sledgehammer to crack a nut, but then again, he did have a scrim with net to sell...

Nomad Photographers's picture

Nice effect yes. And how unpractical ! The more I shoot, the more I look forward to more and more compact solutions for light and modifiers. A large reflector is pain in the back enough IMO !

Jason Vinson's picture

I think it depends on what you are shooting. If you are setting up a production set then this is a perfect solution. Of you are run and gunning at wedding, then not so much.

Robert Feliciano's picture

Good video and nice tip, though I find the vignetting distracting in the above example.
I have the 6x6 frame, but since I need the frame for the diffuser, I may go with Lane's suggestion and save $162.

Omid Daghighi's picture

I have to agree. I prefer the background without scrim

Olafs Osh's picture

The hardest part in this scenario is having two assistants ;]

Sergio Miranda's picture

I have a tip for windy environments, specially like the one we see in this video: Each of the stands that hold the frame and the net have three legs. You just need to aim one of those three in the same direction the wind is blowing. Therefore wind will try and blow the stand, but find that the leg itself has the equilibrium point right against it. You will still have to put some sandbags to the stand, but probably a lot less than the ones used in the video!!

Jason Vinson's picture

That would definitely help! But I still wouldn't trust that large of a wind catcher to go unattended.

B In SEA's picture

That's a great look. Unfortunately it would take a really huge scrim if you wanted more of a 35-50mm environmental portrait.