Another Fluorescent question

[Ralph Tabith]

I will be shooting a short in an asian food store at nightime in a few months and want to do my homework as best as I can. I understand that the in house fluorescents will be my main lighting source - which I am not impartial to as I am after Doyles look in "Fallen angels," with those lovely greens.

 

I searched the threads and I gleaned the fact that Doyle push processed on the movie alot, on Fuji 250T?. I have some stock left over to shoot, would this be viable?/ Kodak 500 T and some VISION2 200T amongst others. How does tungsten film fair under fluorescents, and is there any magic tricks for flicker?

 

Thanks for your time!

[Robert Starling SOC]

I will be shooting a short in an asian food store at nightime in a few months and want to do my homework as best as I can. I understand that the in house fluorescents will be my main lighting source - which I am not impartial to as I am after Doyles look in "Fallen angels," with those lovely greens.

 

Hi Ralph, I've shot quite a few flourescent interiors with Fuji Tungsten; with cool white you'll get a very blue cast; not the typical green you'll get with daylight film. I have been most pleased with the results using CC50R or CC60R filtration for clean whites; assuming you have no other light sources. However, the days of simple flourescent filtration are long-gone now with all the hybrid variations of tubes and it's not uncommon to have a variety of tubes in store fixtures; both in age and color. The engineering guys rarely pay much attention to the brand or color; just the cost. Is there is any way you can do a test, even with a still camera and Fuji Tungsten? Try to take a MacBeth or other color chart if you can as well.

 

Good luck!

 

Robert Starling, SOC

Steadicam Owner Operator

Las Vegas

[David Mullen ASC]

I find that for Cool Whites I need to use tungsten stock if I want that strong cyan look. Cool Whites are basically around 4800K to 5000K with green in them, so if you use a daylight stock (5500K), there is no blue at all, just the green spike, so they look more sickly green-yellow, not deep blue-green.

 

Also, the cheapest Cool White bulbs from the hardware store have the worst CRI rating, and thus give you the most green.

 

You can get a faint flicker by shooting at an "unsafe" speed but otherwise, you need to use something like a flicker box or dimmer -- you'll eventually fry the ballast though.

 

Here is a digital snapshot of a room I lit with Cool Whites (on a wall fixture and in the Kino barely visible on the left), the camera set to tungsten balance. Note the tungsten practical in the f.g.:

 

 

As far as stock, remember that "Fallen Angels" was shot in 35mm; I assume you're shooting in 16mm because of the subforum. Of course, the DVD of the movie is not a very good transfer and makes it look like a 16mm movie...

[Ralph Tabith]

I find that for Cool Whites I need to use tungsten stock if I want that strong cyan look. Cool Whites are basically around 4800K to 5000K with green in them, so if you use a daylight stock (5500K), there is no blue at all, just the green spike, so they look more sickly green-yellow, not deep blue-green.

 

Also, the cheapest Cool White bulbs from the hardware store have the worst CRI rating, and thus give you the most green.

 

As far as stock, remember that "Fallen Angels" was shot in 35mm; I assume you're shooting in 16mm because of the subforum. Of course, the DVD of the movie is not a very good transfer and makes it look like a 16mm movie...

 

Would you advise me buying a temperature meter in order to see what the bulbs are running at (By finding the temperature, does that tell you what kind of fluorescent it is?) So tungsten balanced film would bring out those lovely colours. Would you suggest push processing the film?

 

I walked around the location today and could clearly see that one of the bulbs was flickering, i didnt have time to see what make the bulbs were. Is filming at under 1/48 the rule of thumb for a non "flickery" image?

 

I definitely want to emulate that tone in your image./ thanks Robert and David

Edited October 1, 2007 by Ralph Tabith

[David Mullen ASC]

If you can see it flickering, it's a bad ballast or bad bulb and it will flicker on film too.

 

The flickering problem with 60hz AC discharge lamps is a separate issue than flicker you see with your own eyes. That has to do with capturing a different amount of the light's sine waves in each frame, creating a pulsing on film that wouldn't have seen with your own eyes on the set.

 

You can look up some of the specs of these tubes online, otherwise, yes, a color temp meter would help, although in terms of warmth or coolness relative to a tungsten or HMI, you can usually see this -- plus in this case, the "Fallen Angels" look, you want the fluorescent to be its own color, you aren't trying to correct for it or match it to other lights.

 

The CRI rating will tell you how good the light is in terms of getting the green spike out, how close to being a full-spectrum source, etc. 100 is "perfect"; anything above 90 is a good rating (Kinos are around 92 to 95 I think), the crappier, cheaper flos with a lot of green (which can be pretty) are in the 70's or so I think.

 

Go to a hardware store and pick up an assortment. Most have either a daylight or tungsten bias for starters (Cool or Warm).

[Ralph Tabith]

The flickering problem with 60hz AC discharge lamps is a separate issue than flicker you see with your own eyes. That has to do with capturing a different amount of the light's sine waves in each frame, creating a pulsing on film that wouldn't have seen with your own eyes on the set.

 

Is there anyway to compensate for this? By the way, I am in the UK so it would be 50hz..

Edited October 1, 2007 by Ralph Tabith

[David Mullen ASC]

Is there anyway to compensate for this?

 

You have to be shooting crystal-sync at a "safe" camera/shutter speed. There are charts for this.

 

24 fps crystal-sync with a 180 degree shutter is "safe" for 60Hz; 144 degrees is perfect (because 24 fps with a 144 degree shutter is 1/60th of a second exposure time.) 48 fps with a 144 degree shutter also works.

 

Obviously 30 fps crystal-sync with a 180 degree shutter is perfect. 60 fps / 180 degrees works great, etc.

 

24 fps with a wild or constant speed motor is not safe.

 

Obviously the numbers are different for 50Hz countries.

 

There are "flicker-free" ballasts made for fluorescents, aka high-frequency ballasts, which are pretty much safe at any speed. Kinos use those.

[Ralph Tabith]

You have to be shooting crystal-sync at a "safe" camera/shutter speed. There are charts for this.

 

Obviously the numbers are different for 50Hz countries.

 

There are "flicker-free" ballasts made for fluorescents, aka high-frequency ballasts, which are pretty much safe at any speed. Kinos use those.

 

Thanks for all the info, you could earn a fortune if you charge by the hour!:)

[John Sprung]

Would you advise me buying a temperature meter in order to see what the bulbs are running at (By finding the temperature, does that tell you what kind of fluorescent it is?)

Flourescents don't have color temperatures. CT meters are only really valid for tungsten, sunlight, fire, and anything else that glows because it's very hot. If you want to get into the theory behind it, google around for stuff on the CIE 1931 chromaticity diagram, and look at the little color temperature locus in the middle of it. There is a thing called correlated color temperature (CCT) for flourescents, but it's about as bogus as shop vac horsepower.

 

If you just want to know what particular flourescents will do to film, shoot tests. You could also use a junk DVD or CD to look at the spectral distribution of your flourescents. When you get it lined up right, you'll see a strong green band. Make some notes on where the other strong colors are in the mix, and compare those notes with the film tests.

 

 

 

-- J.S.

[Tim Carroll]

You have to be shooting crystal-sync at a "safe" camera/shutter speed. There are charts for this.

 

24 fps crystal-sync with a 180 degree shutter is "safe" for 60Hz; 144 degrees is perfect (because 24 fps with a 144 degree shutter is 1/60th of a second exposure time.) 48 fps with a 144 degree shutter also works.

 

Obviously 30 fps crystal-sync with a 180 degree shutter is perfect. 60 fps / 180 degrees works great, etc.

 

24 fps with a wild or constant speed motor is not safe.

 

David,

 

With a camera with a 172.8º shutter, running at cyrstal speed 24 fps, is that going to give flicker with 60Hz flourescents? And do you have a link to the chart you refer to?

 

Thanks,

-Tim

[David Mullen ASC]

At 24 fps crystal-sync, assuming the flo's ballasts are working fine (I just got screwed on my last show by some that weren't), any shutter angle is pretty much safe, though shorter than 90 degrees and you risk exposure problems as you are capturing less than one full sine wave of the 60 Hz light, so each time you roll the camera, you may capture, and be in sync with, the sine wave at its peak or valley.

 

I don't have a link to an HMI safe speed chart.

[Tim Carroll]

At 24 fps crystal-sync, assuming the flo's ballasts are working fine (I just got screwed on my last show by some that weren't), any shutter angle is pretty much safe, though shorter than 90 degrees and you risk exposure problems as you are capturing less than one full sine wave of the 60 Hz light, so each time you roll the camera, you may capture, and be in sync with, the sine wave at its peak or valley.

 

I don't have a link to an HMI safe speed chart.

 

 

Thanks David.

 

-Tim

[Ralph Tabith]

" The other major problem created by fluorescent light is the flicker you often get as a result of fluorescent being a pulsating source. If it?s frequency of its power supply isn?t compatible with the camera speed, then the light will fluctuate on the filmed image. Also, if it?s not compatible with the shutter angle of the camera, the same thing will occur. The best combinations of frequency, film speed and shutter opening are as follows for film cameras:

 

*

 

50 kHz.?25fps with any shutter opening

*

 

50 kHz ?24fps with a shutter opening of 170?175 degree opening

*

 

60 kHz--24fps with a shutter angle of 144 or 180 degrees.

 

Don?t use fluorescent sources for creating slow motion effects by shooting at 48fps or higher. You will not be able to get rid of the pulsation of the light -- at least that?s my unfortunate experience.

 

Fluorescent lighting is a common source of light on locations. In documentary, you encounter it constantly. Student films frequently are plagued with poor handling of fluorescent light. If you take into consideration its properties, you can work with it and integrate it into the look of your scene. If you're working on tape, you?ll immediately see it?s effect on your scene if you have a broadcast and calibrated monitor on location. When shooting on tape, it?s always good to make a camera report noting that fluorescent light was used to alert the editor of the need to correct color. " quoted from here

 

Ok, this might be a simplification but its seems to correlate to what I have read in this thread. I only have a Bolex rex 5 and an ebm at my disposal so I will go and find a crystal motor. any other advice always appreciated thank you.

[Ralph Tabith]

Does anyone know if crystal sync motors are being made for bolex's anymore, i contacted duall but they said that the one I was after is not being manufactured anymore....?

[Michael Althaus]

I just moved to america and noticed some flickering with my Pal camera. What would be a save shutter angle to set when shooting 25p. When I do the math it should be 150 degrees, right? anything else nearer to 180?

[Michael Nash]

I just moved to america and noticed some flickering with my Pal camera. What would be a save shutter angle to set when shooting 25p. When I do the math it should be 150 degrees, right? anything else nearer to 180?

 

Try setting your shutterspeed to 1/60 second, or a 150 degree shutter angle (at 25 fps). The difference in exposure and motion blur is negligible.

[Mark Lyon IMPOSTOR]

And do you have a link to the chart you refer to?

 

Thanks,

-Tim

 

http://www.cinematographyelectronics.com/i...lickerfree.html

[Tim Carroll]

http://www.cinematographyelectronics.com/i...lickerfree.html

 

Thanks Mark.

 

-Tim

[Nick Mulder]

Does anyone know if crystal sync motors are being made for bolex's anymore, i contacted duall but they said that the one I was after is not being manufactured anymore....?

 

Well, have a look at the Bolex site...

 

 

you'll also need the crystal sync unit to plug into it (available from Bolex also)

 

They aren't being manufactured as far as I am aware, but there is a seemingly ample supply of unused parts in storage

 

I think you are referring to the Tobin motors though - Clive is concentrating on his new 16mm Telecine devices at the moment, with no apparent plans to keep up the bolex, arri etc.. motors - I personally think there are enough 2nd hand floating around eBay etc... to keep up with the demand so it was a wise decision on his behalf.

 

He announced it here in the forums a while back - do a search ;)

[Ralph Tabith]

Clive is concentrating on his new 16mm Telecine devices at the moment, with no apparent plans to keep up the bolex, arri etc.. motors - I personally think there are enough 2nd hand floating around eBay etc... to keep up with the demand so it was a wise decision on his behalf.

 

He announced it here in the forums a while back - do a search ;)

 

Thanks Nick, a friend is buying one from Clive via ebay as we speak!