Using cellophane with lights

[MileCreations]

So I currently have a red head and a blondie in my possession which both produce a yellow kind of light. I'm filming a night time kind of shot and want the lights to be more of a blue colour as I've been told blue light on the background reduces grain. Not to mention that the scene looks too yellow even when I've desaturated in camera.

I was wondering if it were dangerous to put some blue cellophane over the light (obviously not physically touching the light) to make it closer to the colour I want? The lights heat up quite a bit so I wasn't really sure.

EDIT: I've had a look around google and some people have suggested it before, but they're using examples of just work lights which aren't quite as powerful as the ones I have I don't think

 

[jax_rox]

Few things:

The 'yellow' light is a tungsten balance (ie 3200k). If you set your camera to a lower WB setting, that yellow light will look blue (try 2500k, or 2000k).

Blue light does not reduce noise, it's more the actual presence of light that reduces noise. It doesn't matter what colour that light is.

Lastly, redheads and especially blondies are hugely powerful, and produce an enormous amount of heat. Cellophane is not designed to withstand those kinds of heat and will heat up very quickly, and likely melt or burn, even if pegged to the barn doors. I've had blondies burn the colour out of gels before. It's a much, much safer and easier bet to simply grab some gels.

You can get them online for ~$6. CTB or 1/2CTB will probably work well. Keep in mind though, that you cut about 70% of a tungsten light output when using full CTB gel on it.

Also, make sure when using open face lights that you keep the mesh on them, and try not to point them directly at someone's face - their bulbs can blow really easily, and because of their design they often smash/explode when they blow. Also, make sure you never touch the bulb with your uncovered hands, even when the light is off and cool.

 

[dlevanchuk]

Lastly, redheads and especially blondies are hugely powerful

i'm getting lost with the term over here, unless we're talking about ladies what types of light bulb are those?

 

[dlevanchuk]

Oh and cellopohance isn't thick enough to do a dramatic change. As jax suggested, use CTB (common to blue) gels, but try to use a fluorescent light bulb with 32k temperature grade (the box usually says warm white). They don't heat up as bad as regular bulb. Oh, and i havent seen a light bulb that goes higher than 100w, but its still good for close ups.

I picked a set of six in our local house improvement store for 9 bucks.

 

[jax_rox]

i'm getting lost with the term over here, unless we're talking about ladies what types of light bulb are those?

800w and 2000w tungsten lights

They're named for their distinctive body colours:

They don't take normal household bulbs.

CTB (common to blue) gels [...] fluorescent light bulb with 32k temperature grade (the box usually says warm white). They don't heat up as bad as a regular light bulb. Oh, and i havent seen a light bulb that goes higher than 100w, but its still good for close ups.

Blondies and redheads are specialised film lights, with 800w and 2000w power draws, so a normal household bulb doesn't fit in, and if it could it would explode or blow straight away.

Also, CTB stands for Colour Temperature Blue

 

[MileCreations]

Unfortunately I don't think I have that level of control on my camera. I do have a tungsten preset which I hadn't actually thought to use, so that may at least help. I'm on an SLR, any hints for controlling the WB like that?

Oh I know that it isn't just blue that reduces noise, just that in a dark scene a blue light makes it look like it's still a dark background, apparently.

Ok So I'll try and pick up some gels then, hopefully by the time I shoot next week...

I wasn't planning on removing the mesh I have had one blow before, about this time last year, though the glass didn't physically break, we just then had less lights to work with.

Any suggestions for Australian sellers other than eBay?

 

[MileCreations]

800w and 2000w tungsten lights


Also, CTB stands for Colour Temperature Blue

Oh and cellopohance isn't thick enough to do a dramatic change. As jax suggested, use CTB (common to blue) gels, but try to use a fluorescent light bulb with 32k temperature grade (the box usually says warm white). They don't heat up as bad as regular bulb. Oh, and i havent seen a light bulb that goes higher than 100w, but its still good for close ups.

I got a little lost on this too, but went and searched and discovered many new things. Thankyou Wikipedia

 

[dlevanchuk]

Also, CTB stands for Colour Temperature Blue

Oh sh8T! At my day job we have same abbreviation CTB that stands for "common to blue". Yes, colour temp blue

Thanks for clarification!


MC, what camera you got?

 

[MileCreations]

Also the redhead is about the size of the one in the image but the blondie is much bigger. Diameter of the blondie is probably about 30cm

 

[MileCreations]

Jax is this the type?

http://www.videoguys.com.au/Shop/p/...ng-filter-packs-ct-blues-lee-ctb.html?cat=510

Though they are out of office till 7th of January which is too late for me

 

[jax_rox]

Unfortunately I don't think I have that level of control on my camera. I do have a tungsten preset which I hadn't actually thought to use, so that may at least help. I'm on an SLR, any hints for controlling the WB like that?

Some DSLRs only have presets, though I'm not sure if there's a WB preset lower than 3200k. Others have a selectable WB in the menu where you can dial in an exact colour temp setting. Not sure what camera you have, so I can't advise other than to check your manual.

Oh I know that it isn't just blue that reduces noise, just that in a dark scene a blue light makes it look like it's still a dark background, apparently.

Hm, in my experience the difference between day and night relies on the amount of fill light you put into a scene. I've lit scenes on stages that look like night time until you fill a bit and it looks like mid-afternoon. Blue background can sometimes look like moonlight or streetlight, depending on how you set the light. You may want to 1/2 or full diff the light as well for a moonlight feel, depending on the type of moonlight you're going for. Night scenes generally rely on a lot of backlighting. Be careful of overdoing it, because an overdone 'moonlight' blue light look can look like you've just thrown up a blue light behind them.

Any suggestions for Australian sellers other than eBay?

Lemac, Videocraft or John Barry Sales for shop-front stores. Gel sheets are ~$20 though, compared to ~$6+shipping on eBay.

EDIT:
You're looking for something like this:
www.videoguys.com.au/Shop/p/3623/le...correcting-lighting-filter-le201.html?cat=495

THe pack that you linked looks like it should actually be okay, but the picture is of a Lee swatchbook, so I'd want to double check before spending $80 on a swatch book
Assuming they are in fact full sheets, that pack would consist of CTB, 1/2 CTB, Double CTB, 1/4 CTB, 1/8 CTB and 3/4 CTB.
You can fold gels over doubling their effect, so you could get a bunch of half or quarter sheets (depending how much surface area you need to cover - you couldn't fold a gel over a blondie), but the mired shifts are slightly different (ie a 1/2 CTB folded over is a slightly different colour to a full CTB)

 

[MileCreations]

Some DSLRs only have presets, though I'm not sure if there's a WB preset lower than 3200k. Others have a selectable WB in the menu where you can dial in an exact colour temp setting. Not sure what camera you have, so I can't advise other than to check your manual.

It's the 600D/t3i. I can't find a specific place to dial in a number of my own, but there is a feature that lets you take a photo of something 'white' and then it adjusts accordingly to what it now thinks is white. There's another setting but it appears to be only present in the photo menus, no the video one.

Hm, in my experience the difference between day and night relies on the amount of fill light you put into a scene. I've lit scenes on stages that look like night time until you fill a bit and it looks like mid-afternoon. Blue background can sometimes look like moonlight or streetlight, depending on how you set the light. You may want to 1/2 or full diff the light as well for a moonlight feel, depending on the type of moonlight you're going for. Night scenes generally rely on a lot of backlighting. Be careful of overdoing it, because an overdone 'moonlight' blue light look can look like you've just thrown up a blue light behind them.

Well actually I should have mentioned I'm more looking for a streetlight/moonlight kind of look.

Lemac, Videocraft or John Barry Sales for shop-front stores. Gel sheets are ~$20 though, compared to ~$6+shipping on eBay.

John Barry is the one I was trying to remember. Postage is just as much as the actual gel though :/

You're looking for something like this:
www.videoguys.com.au/Shop/p/3623/le...correcting-lighting-filter-le201.html?cat=495

Thanks

 

[Zensteve]

Unfortunately I don't think I have that level of control on my camera. I do have a tungsten preset which I hadn't actually thought to use, so that may at least help.

You have a T2i, right? Install Magic Lantern, and you can dial in the kelvin temp in increments of 100.

 

[knightly]

Here's the set I have (actually 2 of them for all of my needs): http://www.filmtools.com/lee-filters-master-location-lighting-pack.html

It's a little bit of an investment, but I use them on every light on every shot.

Comes with Diffusion to soften the light, CTB to match tungsten to daylight and CTO to match daylight balanced sources to tungsten (Color Temperature Orange). They come in varying strengths (1/4, 1/2, full)

You use C47 Media Attachment Clips (c47's) to attach them to the bardoors of the lights:

More light allows you to drop the ISO setting of your camera and that gets rid of the grain in your shot... more light = less grain because you're not turning the sensor up to 11.

Select the "Tungsten" setting (picture of a regular light bulb)
Take a picture of an peach piece of scrapbooking paper being lit by one of your lights (different intensities of orange/peach will produce stronger results)
Use that picture to set a custom white balance profile for your camera (it's in the manual) which will push it quite blue.

 

[jax_rox]

Also, coathangers are often attached to barn doors to get the gel (especially diffusion) out in front of the light a bit, as it sometimes works better a little in front of the barn doors, especially on high heat machines like blondies.

Just be careful power-wise when mixing blondies and redheads - you can have three redheads or one blondie per circuit, but you couldn't have one blondie and one redhead on one circuit.

 

[MileCreations]

You have a T2i, right? Install Magic Lantern, and you can dial in the kelvin temp in increments of 100.

T3i yeah I've got it sitting on the computer waiting to decide if the risk is worth it, had it there over a month and have read the manual and stuff several times

Also, coathangers are often attached to barn doors to get the gel (especially diffusion) out in front of the light a bit, as it sometimes works better a little in front of the barn doors, especially on high heat machines like blondies.

Just be careful power-wise when mixing blondies and redheads - you can have three redheads or one blondie per circuit, but you couldn't have one blondie and one redhead on one circuit.

Ok that will make things interesting ... :/

 

[jax_rox]

Ok that will make things interesting ... :/

If you have access to the circuit breakers, checking circuits are easy - often they're labelled, and all you have to do is get something low-powered like an iPhone charger, turn of all the circuit breakers except one and go round with the charger and see what is still powering. Shouldn't take long at all, especially if there are a small amount of circuits. You sohuld label each circuit with a different colour of camera tape.

As long as you've got two circuits, you'll be okay, and most houses have at least two.

 

[MileCreations]

If you have access to the circuit breakers, checking circuits are easy - often they're labelled, and all you have to do is get something low-powered like an iPhone charger, turn of all the circuit breakers except one and go round with the charger and see what is still powering. Shouldn't take long at all, especially if there are a small amount of circuits. You sohuld label each circuit with a different colour of camera tape.

As long as you've got two circuits, you'll be okay, and most houses have at least two.

I'm filming in my shed which will have an extension cable from the house to the shed, just means I need two extension cables now.

What are the side effects of using both on one?

 

[JWerner]

The T3i doesn't have the ability to set the white balance using Kelvin, but you can use white balance correction. The details are in the manual under "Adjusting the Color Tone for the Light Source", on page 119 if the manual is the same as the one distributed in the US. This method will probably be more consistent than setting a custom balance from a colored card, it allows you to shift in 5 mired increments.

 

[jax_rox]

The result of attempting to use both lights on one circuit will blow the circuit. It's not necessarily hazardous (unless you don't have circuit breakers) but its annoying and ultimately means you won't get more than a few minutes with both lights on, effectively rendering your lighting setup useless.