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The basics of flagging?


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Okay, this might be a dumb question, but it has been on my mind for a while now. I'm pretty okay with lighting and such, but I really don't know how to flag. Usually I don't see the need to flag my instruments, but I'm pretty sure most of my setups would benefit from some flagging. So the real question rather is why to flag and from where? Post some examples maybe?

 

Of course on some occasion it's obvious, for example you don't want a light hitting both actors, or the walls. But I really can't seem to finesse flagging, I feel I'm just working in broad strokes. And how on earth are you supposed to flag big soft units like 12' x 12' frames on location? Or should one not use big soft sources in small spaces?

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Flags provide the one thing that nearly every DP appreciates most when it comes to lighting, and that's "control".

 

You don't want light spilling onto that wall? Flag it. There's a hot spot in frame that you don't want? Flag it. Is that light causing some lens flare? Flag it.

 

Asking about the many uses of a flag IS NOT a dumb question. You'd be surprised how many times I have to explain to student grips & gaffers WHY I need a flag by that light. You're doing yourself a favor by asking here rather than making it an issue for someone else on set.

 

Usually you can get along fine just using the barndoors that come with your lights, but sometimes it's just not enough. The finesse of flagging is pretty simple, just put the flag between the light source and the space where you don't want light...and make sure it's out of frame :)

 

For on location use, I usually use flags just for negative fill if I need a bit more contrast. Placing a flag in front of a giant 12x12 silk will prove to be in vain, but you can still flag specific objects in your frame that you feel might be too bright or distracting to the eye.

Edited by Jonathan Bowerbank
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When working with big soft units, think of flagging (usually also big) as a way of controlling the degree of fall-off of the soft light on the sides, top, or bottom. It won't be a dramatic effect, but it could make the difference between having a wall look too bright or the bottom half of a desk or the top part of a wall. You're sculpting the soft light very gently.

 

Flags can also be used to get rid of the reflection of the soft light in some reflective object, like a photo on a wall or a glass window in the b.g.

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Great topic!

 

Don't be afraid to ask questions, I always ask questions on here, I wouldn't be surprised if people are annoyed by it :ph34r:

 

But thats the only way to learn right?

 

Anyway...

 

Is flagging hard light, say from a 1k fresnel easier with barn doors or flags? I have found it quite hard to control light using flags as my desired effect is never really achieved. If I am looking to get a strip of light across the B.G. to add depth the strip would always be always miss-shapen so I would have resort to the barn doors, which seems unprofessional to me.

 

What do you think?

 

Think in terms of using the barn doors first to try and shape the light, if the desired effect cannot be created, then introduce flags. With harder sources such as fresnel lamps, flags can provide very precise shaping of light. Keep in mind, because the barn doors are so close to the source, the edge of the light will be very soft, whereas if you are to flag a light further from the source you can create very hard edges.

 

Cheers,

 

Steve

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When working with big soft units, think of flagging (usually also big) as a way of controlling the degree of fall-off of the soft light on the sides, top, or bottom. It won't be a dramatic effect, but it could make the difference between having a wall look too bright or the bottom half of a desk or the top part of a wall. You're sculpting the soft light very gently.

 

Can you explain more about what you ment by fall-off? I never have had much luck flagging a soft source. On scoops I will use the barn doors, but mostly just to dim the overall amount of soft light coming from the source.

 

Cheers,

 

Steve

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In this case, I really mean controlling spread or spill more than fall-off in intensity, but I figured you could imagine "fall off" as being how the background falls off into darkness.

 

Soft light needs LARGE flags, that's all, and the space to get them in front of the light but out of the shot. But you're never flagging a soft light to get a hard shadowline because that's not really possible unless the flag is almost right up against the object being lit. You're flagging usually to create a gentle shadowing to knock down the spread of the light and mildly direct it.

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This is a good post, I have a question about flagging, too.

 

I've read interviews where DPs have referred to adding flags to remove multiple shadows caused by using multiple lights, like when blasting many high wattage lights thru windows. How is this done? Is it possible to really get rid of multiple shadows when using multiple lights?

 

They usually are complaining about having to do it, or are trying to avoid it, so it must take time and is probably not the best tactic, but I'd just like to know if it ever comes up.

 

thanks

Christian Janss

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This is a good post, I have a question about flagging, too.

 

I've read interviews where DPs have referred to adding flags to remove multiple shadows caused by using multiple lights, like when blasting many high wattage lights thru windows. How is this done? Is it possible to really get rid of multiple shadows when using multiple lights?

 

They usually are complaining about having to do it, or are trying to avoid it, so it must take time and is probably not the best tactic, but I'd just like to know if it ever comes up.

 

thanks

Christian Janss

 

The types of lights these DP's are probably refering to is a Dino or a Maxi Brute, which is essentially several Par lamps on one big fixture. Using them through windows is still fairly common although most DP's prefer the larger single source such as a 12 or 18k. In terms of flagging them, you can take the edges of the beam off where you can see the layering of the shadows. The edge will of course be replaced by the single edge created by the flag. Another technique is to simply defuse the entire fixture. Use something like 216, or a few layers of hampshire frost in a frame, and it will minimalise the multiple shadows. That is to say if thats what you want. Often DP's simply don't mind the look of the layered shadows. Bruno Delbonel's film's for example are full of them. Watch Amelie and count the shadows. Gordon Willis does it alot as well.

 

Cheers,

 

Steve

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If you are using multiple lights to create one effect through one window, like a 12-light MaxiBrute, let's say, you can't really use a flag to get rid of multiple shadows.

 

But you do use flags to separate multiple lights used to create an effect through multiple windows. For example, let's say you have four windows in a row and outside each window was an 18K HMI backed up about 12' or so from the window, to create a sunlight effect.

 

Well, the point is for each light to be dedicated to each window, but each 18K will spill into the surrounding windows on each side too, creating multiple shadows, unless you put up large flags to separate the lights so that each unit's light only falls into the window it is pointed at, with no spill beyond the window.

 

Now, there are many cases where you use smaller flags to reduce spill causing multiple shadows inside a room. You may have two lights, for example, coming from one side, separated so that a person is side-lit by one light, then steps forward a couple of feet until they land in the next lamp's light, parallel to the first light. But that closer light is spilling into the background, along with the farther light, so that some object on the wall creates two shadows, unless you flagged off one of the two lights from the background wall.

 

You actually notice that double-shadow effect in real life when a room is naturally lit by two windows on one wall. You get a soft double-shadow effect.

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You actually notice that double-shadow effect in real life when a room is naturally lit by two windows on one wall. You get a soft double-shadow effect.

 

sometimes if this double shadow effect serves for the film script,i think one can let it go...in some cases its true that if the double shadows are too dark,it looks a little odd...

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I think shaping light on set is one of the best parts for me. There are several types that you can use to to cancel out hot spots like David said or to get good lines on certain spots in the frame. Flags come in all kinds of different types like dots, which happen to be among my favorite things.

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And how on earth are you supposed to flag big soft units like 12' x 12' frames on location? Or should one not use big soft sources in small spaces?

 

On large soft sources egg crates are a great way to control excess light.

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all the time working as an apprentice on the sets i have learned that " it's not important what you light but what you dont"

flagging deffinately helps, as taking off unwanted lights make your frame look good

once on an outdoor location shooting against the sun we used negative fill by placing 12'by 12' frames with black cloth attached to take off sky bounce to get rid of unwanted light(clouse ups and mid shots)

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On large soft sources egg crates are a great way to control excess light.

 

I often don't have eggcrates (filmschool) but I've started sticking an appropriately sized flag right in front of my soft sources, perpendicular to the diffusion/silk/chimera face as if it were air I'm trying to direct. I usually put the flag in a vertical position and place another as a topper. It's probably not the best way but it works pretty well as a start and is very quick. My regular crew (as regular as you get in school) knows to do this as a course of habit now.

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Thanks for the great replies!

 

I've been thinking about this a bit more lately and I think my dilemma is almost philosophical in nature. Whenever I'm lighting with only one source, I usually don't shape the light at all. The process in my head goes something like this:

 

"If this scene had been lit by natural light, everything would have fallen in place in brightness wherever it would naturally do, and therefore I probably shouldn't alter the brightness of different objects with flagging/scrimming."

 

Of course a lot depends on the light direction, staging and such.

 

I do use negative fill a lot and I do use toppers/siders whenever there's an obvious need for it.

 

Maybe I'm just being too anal about realism and thinking too much. I guess I'm worried because I see a lot of sets with these dense flag forests and I'm wondering what I'm doing wrong ;)

 

I guess with bigger budgets, bigger sets and bigger units you'll have more opportunities shaping the light...

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That's a really good way to begin. The next step there is to take a 'look' with your meter or on the monitor. Decide what you like and what you don't like. Chances are, there's a way to fix the things you don't like without ruining the feel of realism. Same with bringing out the things you do like.

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"If this scene had been lit by natural light, everything would have fallen in place in brightness wherever it would naturally do, and therefore I probably shouldn't alter the brightness of different objects with flagging/scrimming."

 

Well, think of it this way -- if you're using a large soft light inside a room to simulate a soft window light effect, then in real life, the window itself would be acting as a topper, sider, and bottomer, whereas the soft light in the room spills more in all directions. So using toppers and bottomers on a soft light may actually look more realistic, not less realistic, because in real life it wouldn't be hitting so high up the wall or to the bottom of cabinets, etc.

 

I mean, there's not necessarily anything "real" about a 6'x6' soft light inside a room -- it just feels realistic.

 

Which just comes back around to my belief that realism is just another form of artifice, unless you are exclusively using available light.

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