Question about color temperature and film.

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ironpony

Carbonite Member
I read how when Hollywood uses film that almost all movies are shot with only daylight and tungsten balanced film. But it seems that lot of movies used different kinds of color balanced films. Braveheart for example is shot on cloudy days mostly. And those scenes look like they were shot with films white balanced 6800 Kelvin, rather than daylight, which is 5100 K. The scenes in Braveheart that are shot in the shade look like they are even shot at a higher color temperature than 7000 K. I could be wrong though, or am I? It's just Braveheart but lots of movies look like they were shot higher than 5100 K.
 
You are confusing the issue. The background is chemistry, not physics. For years, film stock was a limiting factor. Each type of film had a whole bunch of characteristics, not just colour temperature. We've done this before, I seem to remember - if you want white to look white, then everything needs to match. get it wrong, and a tint towards a 'new' colour is the result - so the film stock would be ordered to match the lighting, the location, the time of day, the exposure, the look, the grain - all those things. Once exposed the labs who processed it would develop it appropriately - so maybe the DoP would shoot under exposed for a deliberate effect, and get the lab to push the processing to recover the levels. The strange crushing or stretching of the blacks, and the changes to the look were quite well understood and exploited. With video many of these processes have equivalents in electronics - for the better or worst! Now, we have people who's skill is in changing what has been recorded. You talk about colour temperature as if this is what is being changed. They are adjusting the balance of the colour, and can do it overall, or on more precise parts of the picture - that's the skill. If colour balance was 'correct', then white would be white with no processing afterwards. You keep talking numbers, and what you are doing is seeing a colour shift, and assuming that it's a white balance product. They don't shoot movies at the wrong colour temperature, they make choices.

If you look at a more conventional video camera with a turret type colour temperature filter wheel, if you turn it, you can make the picture look more orange or bluey - or maybe you might say warmer or cooler. Leaving the turret set to 3200K on a blue sky day will look 'different'. A white shirt or card won't be white. This is just an effect. Me - I shoot at the correct white balance setting to attempt to preserve colours as what they were to my eye. Then, I can adjust later if I need to change the balance of what I see. I don't change the colour temperature, because tweaking this and tweaking that is distorting the response. No light source would have a tinge of this or a splodge of that in it's light spectrum - I'm creating a 'new' look.

If somebody wishes Braveheart to be greener, bluer, warmer, colder, harder, softer - it's a production decision and not something absolute like white balance colour temperatures. Swap Kodak for Fuji film, and the look changed - despite the colour temperature label on the box!
 
Oh okay. To me their is no such thing as correct white balance since you can color balance a movie to look any way you want to, depending on the look you are going for.
 
We used optical filters extensively when I used to shoot film. Not just CTO or CTB in various densities but reds, greens, yellows, magentas. Shoot tests with different filter packs, combinations of Wratten gelatin filters sandwiched in glass mounts to get to a look for a particular film stock. There used to be choices in film stocks from different companies with different color qualities too.
 
If I want 5600k film shot in daylight to look bluer than the natural colours I'd just pop a colour compensating filter into my matte box, shifting the colour temperature towards blue or I'd shoot it normally and tell the colour timer to add a couple of points of cyan and magenta to the print. Ridiculously simple really...
 
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Oh okay I see. So in film days, perhaps it was easier to use optical filters, rather than a different color balanced film that was not regularly produced. What about in the digital world? There is a scene I want to shoot and I am using streetlights. The street lights are orange but I want them to appear white. I turned down the kelvin temperature to 1500, on my camera. But that does desaturate the image. My collaborators think it looks cool and it works. But it doesn't match the rest of the more saturated footage, such as the interior scenes and daylight scenes.

Would it be better to put a filter on the lens instead to get the orange lights white, or will that just do the same thing and desaturate, and therefore just look the same anyway?
 
paulears said:
If somebody wishes Braveheart to be greener, bluer, warmer, colder, harder, softer - it's a production decision and not something absolute like white balance colour temperatures. Swap Kodak for Fuji film, and the look changed - despite the colour temperature label on the box!
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The Wife preferred the skin tones that Fujifilm delivered vs. Kodak... Since we only shot stills, and only shot 'daylight' film we used flash(*) for light if required. We never did any printing of color prints ourselves, as it was big pain...

But even B&W had subtle differences in color rendition, again we ended up with Fujifilm B&W (And after the Wife got sponsorship from Fujifilm for her seminars... it was sort of 'required'... but I digress...).

With that in mind, we also moved into the digital world with the Fujifilm S2-5 series, which we liked the color balance that the Fujifilm engineers had designed. Canon's seemed to be 'yellowish' at the time, and Nikon had sort of a magenta cast... (oddly the recent Canon 'wonderful' color that some people rave about has struck me as on the magenta/violet side...).

*For me the biggest 'difficulty' in moving into moving pictures has been the 'lack' of massive lighting that a still photographer carries around in their hands with a strobe unit...
 
ironpony said:
Oh okay I see. So in film days, perhaps it was easier to use optical filters, rather than a different color balanced film that was not regularly produced. What about in the digital world? There is a scene I want to shoot and I am using streetlights. The street lights are orange but I want them to appear white. I turned down the kelvin temperature to 1500, on my camera. But that does desaturate the image. My collaborators think it looks cool and it works. But it doesn't match the rest of the more saturated footage, such as the interior scenes and daylight scenes.

Would it be better to put a filter on the lens instead to get the orange lights white, or will that just do the same thing and desaturate, and therefore just look the same anyway?
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You've posted this sort of 'problem' before, and have been told that 'street lamps', typically some form of sodium vapor lamps have a very special output of 'color', and 'no balancing' is to be had from them since they do not produce 'white light' or anything resembling 'white'. The way the 'pros' do this is to use 'white light' from an artificial source, and place filters over said white light to give the impression of the 'yellow street' lights.

Some 'indie' productions go with the 'flow' and embrace the yellow, despite the color rendition going to hell. I've also seen some nolo budget examples where with a 'small amount' of white light, mixed with the 'street lamp' yellow come up with some 'reasonable' results.

The reason for the 'quotes' is that this sort of thing is highly subjective as to what is good, and so, only you can make that decision as to what is 'good' for you, given your budget and resources.

If you really don't like 'yellow light', and can't afford 1000's of K Watts of lighting... don't shoot on the streets...
 
Okay thanks. Well I have shot some test footage with the color temperature turned down to 1500 K, thereby making the sodium lamps white. I showed it to some friends. Half like it and think it gives a cool movie look. The other half say it's too desaturated and that realistic color is better. As long as half like it, I guess that's good enough to use it (shrug). Just so long as it's not too distracting such as when a character is outside with the color at 1500 K, then she walks into a building and it cuts to inside, and we are all of a sudden at 4200 K. If audiences are okay with that change...
 
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ironpony said:
Oh okay I see. So in film days, perhaps it was easier to use optical filters, rather than a different color balanced film that was not regularly produced. What about in the digital world? There is a scene I want to shoot and I am using streetlights. The street lights are orange but I want them to appear white. I turned down the kelvin temperature to 1500, on my camera. But that does desaturate the image. My collaborators think it looks cool and it works. But it doesn't match the rest of the more saturated footage, such as the interior scenes and daylight scenes.

Would it be better to put a filter on the lens instead to get the orange lights white, or will that just do the same thing and desaturate, and therefore just look the same anyway?
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The only choices for film, in terms of colour balance. were daylight or tungsten.

Street lights are a PITA, particularly mercury vapour liamps which don't have a stable colour spectrum. Your best bet is to do a manual white balance at the scene using a gray card and gel any additional lights to match.
 
Few people ever do that. Most of the time, orange lights play as orange. But it doesn't look as bad as you made it out to look. You could get away with bringing the color temp higher than 1500°k if you ask me, it looks rather blue because of all the other non-HPS sources that run at a higher color temp.
 
ironpony said:
How's this shot for getting orange lights white?
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Everything in your video has a purple cast to it, like it was graded to be purple...

Back in the pre-digital days, if you shot reversal film ( i.e. slide film ) you would test your film stock to figure out the correct filter pack for a neutral color balance. Usually this would mean adding CC gel filters ( Cyan, Magenta, Red, Blue, Green, Yellow ) that would come in strengths from 2.5 to 50 CC ( color correction units ), so you might end up with a neutral filter pack like 7.5 CC Magenta, 5 CC Yellow. If the film was "pushed" ( developed longer to increase the sensitivity ) or "pulled" ( under-developed to decrease the sensitivity ), this would slightly effect your neutral CC filter pack so ideally you would modify your filter pack to compensate for the modified processing.

Daylight film had a color temperature rating of 5600 K and Tungsten film had a rating of 3200 K. To adjust the color temperature of your reversal stock you would use Wratten gel filters to either raise or lower the color temperature to match the look you were after.

Wratten 81 amber filters are "warming" filters that come in 100 degree Kelvin increments. Wratten 81 = -100 K, 81A = -200 K, 81B = -300 K, 81C = -400 K, 81D = -500 K, 81E = -600 K, 81F = -700 K.

Wratten 82 blue filters are "cooling" filters that come in 100 degree Kelvin increments. Wratten 82 = +100, 82A = +200, 82B = +300, 82C = +400, 82D = +500, 82E = +600, 82F = +700.


If you shot negative film, then color balance ( i.e. color timing or color correction ) was usually handled when the print was made, so no special "neutral" filtration pack was required when you shot.
 
Okay thanks. The purple is coming from some sign. Perhaps a sign on the bus it looks like, or a sign on the building behind the tree there maybe.
 
ironpony said:
Okay thanks. The purple is coming from some sign. Perhaps a sign on the bus it looks like, or a sign on the building behind the tree there maybe.
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You have over compensated for any yellow/orange of the street lamps, and the result is that all of your colors are whacked. I don't think you have a 'white' in the shot. You seem to have varying shades of blue (perhaps purple...) but on my display the clip has a heavy blue cast.

What you seem to sort of 'fail' to understand, is you will never 'correct' this sort of grab street scene. When a Hollywood production does a 'street' scene, they block off the street, but up massive lights, and then adjust to give the impression of a 'street' scene with controlled amounts of yellow, for the modern age. Back in the olden days, street lights were tungsten, and so they could be 'balanced', by selecting a tungsten film stock (as indicated above...).

One of the reasons for going to 'sodium' or similar lights is the power savings. The other, here in Southern California, and lights were "Low Pressure" Sodium, was to have street lighting that had a particular, and narrow 'spike' in the yellow portion of the visible spectrum. This allowed Mount Palomar to 'filter' out the yellow haze of the growing urban area of San Diego and communities, from their telescope imaging.

One can only 'balance' if there is sufficient Blue, Green, and Red, outside of the dominant color cast. In this case 'yellow'... but Low Pressure Sodium lights have virtually no component in the Blue, and the sensor 'splits' the yellow into Green and Red components, and not very well. High Pressure Sodium has a bit of components outside the fundamental yellow, but not much...

So, again, either you embrace the yellow, or for the nolo budget, use small 'white' lights on the talent or 'near' objects, with the camera balanced to that 'small' white light, and let the 'yellow' street lights go where they may.
 
I'll back this up - good info, explaining what is going on. You need to get your head around what light is made up of. How about this for an analogy?

Let's think about a cheap hifi with a treble and bass control. You can turn up or down either, and the results will be quite well understood - people with no technical background will say it's too bassy, or a bit muffled - to describe too much from maybe 50 to 500Hz, or a lack of much over 3000Hz. However, if you have a 32 band graphic equaliser, you have cut and boost every 3 notes or so on a piano keyboard. The sodium discharge light would be a little like playing a tune on just C and D in the area where your right hand would be. If you turn up or down the bass, nothing much will happen. If you turn down the treble, then those 3 notes drop in volume. The combination of the bass and treble setting are the equivalent of your white balance setting. Normal lighting from the sun, or a tungsten light include all the notes, with one a bit left hand heavy, and the other a bit right hand heavy. The tune belted out on just 2 notes can be very loud - and the light from sodium sources can be very bright, but as we've tried to explain - it's that nicotine colour and nothing much else - so coloured items in the area look very odd?
 
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