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Grey Cards/Color Charts


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#1 Evan Andrew John Prosofsky

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Posted 03 July 2012 - 02:55 PM

Hi,

Up until recently most of my shoots have been extremely run and gun and low budget; I rarely had time to shoot a color chart. That being said, the film has always come back colored beautiful. But I figure it couldn't hurt to get this parsed out because of this my understanding is still a tad shaky.

To confirm -- one would shoot a grey card (or color chart, or both? help) in the lighting they want to be neutral? So what confuses me is then, what do you do in situations where you want the light to be warmer or colder and there is no neutral source?

To clarify let me give an example; I am shooting a scene on 5219 outdoors, the subject is lit by a blazing fire. I expose for the subject lit by the flames, and want the film to turn out exactly as I see it, very warm. If I'm shooting tungsten film without an 85, where would I want the grey card to go? My intuition tells me I would have an on camera light balanced to 3200 that I would shoot the grey card with. That way the color of the flames (lets say 2500K) look slightly warmer, as it does to my eye. Is this correct?

What is normal practice for shooting a grey card or color chart? Is it normal to have an on camera light like this to shoot color charts in situations where there is no neutral lighting? Do you shoot them at the beginning of every scene? Every change in lighting? Please explain :)

Slightly confused and looking forward to your answers, thankyou!

Evan
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#2 David Mullen ASC

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Posted 03 July 2012 - 03:02 PM

A grey card on film is just a communication tool between you and a colorist if you aren't there to supervise the color-correction -- it's a way of telling the colorist what is neutral and what, relative to that, is colored, or it's a way of correcting something to be neutral. Often the problem is that without a reference, a colorist will try to make something neutral on faces unless it is obviously not meant to be neutral (if there's a fire in the shot and a face lit by the fire, most colorists will figure that some sort of warmth is natural.)

A grey card is also a tool to tell you if a color bias in a print was your doing or the print timer's doing -- if the whole print looks pink along with the grey card, you know that it was printed pink, but if the grey card is neutral but everything the follows is pink, it is likely that it was lit to be pink.

As for getting the grey card to be neutral in a scene lit by fire, you need to bring a 3200K light (if that's what you want to be your white reference) for the card, shoot the card under that light and then turn if off for the scene.
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#3 Adrian Sierkowski

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Posted 03 July 2012 - 03:04 PM

Hey Evan;
the way I do it is such:

When I have a scene, let's say in a house, where I want it warm. I will shoot a grey-card before the scene (and/or a color chart, best to have both) under 3200K lighting, and instruct the dailiest colorist to correct to the grey-cards if present.

this will cause him/her to correct for 3200K and thussly my "warm" interior will come back warm.

Same woudl be if I was doing a "cool" interior.

I don't find it necessary to do it for every lighting change-- let's face it, we're generally using the same lights, or for scenes where you want it back balanced neutral.

What is important is to make sure the card isn't over or under exposed @ all, as they will be setting white and black levels to it as well as color.

Also, honestly, I don't always have time (or spare film) for the card, in such cases I just make sure that my shooting notes go along for a ride with the neg.

You can have an on-camera light, or any light, so long as it's properly color balanced for what you want to be neutral and bright enough to illuminate the card.
Sometimes it's nice to throw a skin tone (pa) in there too.
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#4 Evan Andrew John Prosofsky

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Posted 03 July 2012 - 03:20 PM

Amazing, all makes sense.

David, Adrian, thanks for the fast responses and incredibly helpful ones at that :) You're the best!

Evan
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#5 David Mullen ASC

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Posted 03 July 2012 - 03:43 PM

Keep in mind that the light on the grey card doesn't always have to be neutral, it's just that it will be timed to become neutral. This allows you to shift the color of a scene creatively or correct out a color bias like under greenish fluorescent lighting. If I want a night interior to be very warm, I sometimes put a 1/4 CTB gel on the grey scale light so that the card is slightly blue-ish, and thus when timed to neutral, the scene that follows will have a warm bias. Outside I use color filters for that effect -- for example, if using daylight balanced film, you can use a pale blue filter on the lens when doing the grey card and then pulling it for the scene, again to get the scene timed warmer. Or on tungsten balanced film, you could shoot the grey card with an 81EF but then the scene with an 85 filter, so that the image will be timed to make the 81EF card look neutral so that when switching to the heavier 85 filter, the scene will look warmer.

Besides writing "time to grey card at head of roll" on the camera report, I also carry a collection of signs that I shoot right after the grey card, in the same neutral light. The sign might say: "NOTE TO COLORIST: WARM, GOLDEN TONE" for example.

I have all sorts of cards printed up, saying things like "DEEP BLUE TWILIGHT" or "PALE BLUE MOONLIGHT" or "DEEP ORANGE FIRELIGHT" or "SLIGHT GOLDEN TONE" or "SLIGHTLY COLD (BLUE) TONE", etc.

The other advantage to the sign is that anyone who watches dailies and sees the sign knows the visual intent of the scene, color-wise, even if mistimed.
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#6 Adrian Sierkowski

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Posted 03 July 2012 - 04:26 PM

David, you are a wealthy of great ideas I have been stealing for my own benefit. Time to hop to get some sickie letters and card stock!
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#7 Evan Andrew John Prosofsky

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Posted 03 July 2012 - 05:55 PM

Keep in mind that the light on the grey card doesn't always have to be neutral, it's just that it will be timed to become neutral. This allows you to shift the color of a scene creatively or correct out a color bias like under greenish fluorescent lighting. If I want a night interior to be very warm, I sometimes put a 1/4 CTB gel on the grey scale light so that the card is slightly blue-ish, and thus when timed to neutral, the scene that follows will have a warm bias. Outside I use color filters for that effect -- for example, if using daylight balanced film, you can use a pale blue filter on the lens when doing the grey card and then pulling it for the scene, again to get the scene timed warmer. Or on tungsten balanced film, you could shoot the grey card with an 81EF but then the scene with an 85 filter, so that the image will be timed to make the 81EF card look neutral so that when switching to the heavier 85 filter, the scene will look warmer.

Besides writing "time to grey card at head of roll" on the camera report, I also carry a collection of signs that I shoot right after the grey card, in the same neutral light. The sign might say: "NOTE TO COLORIST: WARM, GOLDEN TONE" for example.

I have all sorts of cards printed up, saying things like "DEEP BLUE TWILIGHT" or "PALE BLUE MOONLIGHT" or "DEEP ORANGE FIRELIGHT" or "SLIGHT GOLDEN TONE" or "SLIGHTLY COLD (BLUE) TONE", etc.

The other advantage to the sign is that anyone who watches dailies and sees the sign knows the visual intent of the scene, color-wise, even if mistimed.

Excellent advise on the notation, definitely going to utilize that next time I shoot. Thanks David
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#8 Gregory Middleton

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Posted 03 July 2012 - 06:59 PM

Another great reason for shooting a note or sign as David calls them, with your chart is that this information is never 'lost' . The colourist will always see it.
I used a dry erase board to shoot notes with charts on The Killing this year. With the same colorist you can quickly get into a shorthand.

Greg


Hi,

Up until recently most of my shoots have been extremely run and gun and low budget; I rarely had time to shoot a color chart. That being said, the film has always come back colored beautiful. But I figure it couldn't hurt to get this parsed out because of this my understanding is still a tad shaky.

To confirm -- one would shoot a grey card (or color chart, or both? help) in the lighting they want to be neutral? So what confuses me is then, what do you do in situations where you want the light to be warmer or colder and there is no neutral source?

To clarify let me give an example; I am shooting a scene on 5219 outdoors, the subject is lit by a blazing fire. I expose for the subject lit by the flames, and want the film to turn out exactly as I see it, very warm. If I'm shooting tungsten film without an 85, where would I want the grey card to go? My intuition tells me I would have an on camera light balanced to 3200 that I would shoot the grey card with. That way the color of the flames (lets say 2500K) look slightly warmer, as it does to my eye. Is this correct?

What is normal practice for shooting a grey card or color chart? Is it normal to have an on camera light like this to shoot color charts in situations where there is no neutral lighting? Do you shoot them at the beginning of every scene? Every change in lighting? Please explain :)

Slightly confused and looking forward to your answers, thankyou!

Evan


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#9 Evan Andrew John Prosofsky

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Posted 06 July 2012 - 10:32 AM

Hey everyone I actually just thought of another question.

When you have a source that you're exposing for in the scene, deciding where to put the grey card is easy. But what about situations where you're doing a mixed exposure? Eg. Shooting in a dense forest where patches of dappled sunlight break through the trees. You average the exposure between the shadows and the dappled sunlight so the shadows are 1 under and the dapples are 2 over. Where does the grey card go? And wouldn't the colorist ruin the shot by timing to either the shadows or the highlights depending on the card?

Still confused. Sorry, haha
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#10 David Mullen ASC

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Posted 06 July 2012 - 11:11 AM

Hey everyone I actually just thought of another question.

When you have a source that you're exposing for in the scene, deciding where to put the grey card is easy. But what about situations where you're doing a mixed exposure? Eg. Shooting in a dense forest where patches of dappled sunlight break through the trees. You average the exposure between the shadows and the dappled sunlight so the shadows are 1 under and the dapples are 2 over. Where does the grey card go? And wouldn't the colorist ruin the shot by timing to either the shadows or the highlights depending on the card?

Still confused. Sorry, haha


You'd want to fill the frame with the card in flat light so that the colorist isn't trying to artfully strike some compromise between the setting and the card, they just have to time the card to look neutral in color and brightness. How you expose the scene that follows the card is up to you.

The trick in the woods in dappled light is whether to put the card in a patch of warmer sun or cooler shade.
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#11 David Mullen ASC

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Posted 06 July 2012 - 11:15 AM

My problem with day exteriors is that often you set up at sunrise when the shade is very cold and the sun is very warm, if up yet. This is where having a HMI for the card can help, but if not, you do the best you can and sometimes shoot another grey card later in the morning when the sun is closer to white.
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#12 Evan Andrew John Prosofsky

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Posted 06 July 2012 - 03:21 PM

You'd want to fill the frame with the card in flat light so that the colorist isn't trying to artfully strike some compromise between the setting and the card, they just have to time the card to look neutral in color and brightness. How you expose the scene that follows the card is up to you.

The trick in the woods in dappled light is whether to put the card in a patch of warmer sun or cooler shade.

I must still be confused. Are grey cards/color charts not used by the colorist to set the overall exposure/color balance of the scene? So if I shot a color chart in flat light, but then the scene that directly follows was exposed for say, the highlights, would the colorist not then try and correct that based on my color chart? Would I have to put a note beside the color chart saying something about the look? Like "bright blooming highlights coming through trees, dark moody forest" so that they know not to do so? Sorry David.
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#13 David Mullen ASC

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Posted 06 July 2012 - 04:49 PM

I must still be confused. Are grey cards/color charts not used by the colorist to set the overall exposure/color balance of the scene? So if I shot a color chart in flat light, but then the scene that directly follows was exposed for say, the highlights, would the colorist not then try and correct that based on my color chart? Would I have to put a note beside the color chart saying something about the look? Like "bright blooming highlights coming through trees, dark moody forest" so that they know not to do so? Sorry David.


Not really, the grey card is to tell the colorist what neutral base to start from, the scene that follows the card shouldn't require that the colorist do anything. Generally dailies are one-light anyway so after the card is timed correctly in theory everything that follows should look however you shot without any creative adjustment by the colorist. Now if you were doing scene-to-scene corrections, the grey card is still a good reference as a starting point for the colorist but after that they'd be making changes so even if the card looked correct, if the scene that followed looked wrong in dailies you wouldn't know if it was you who made a mistake or the colorist. If you really want the colorist to time the scene for a certain look, playing with gamma or secondaries, etc. then you would need a more elaborate system, like sending the colorist a corrected still photo or lots of notes, etc. Having them just time the grey card shot in flat light so that there is no room for creative input or error, no possible misinterpretation, implies that what follows shouldn't need adjusting, that you're doing all the work to create the look.

Without a grey card even with a one-light daily, the colorist has to base how to transfer the entire roll on how the first shot looks, and therefore might time a sunset scene to look midday or a blue moonlit interior to look like a daylight interior without further information. They can't tell whether a shot is intentionally or accidentally dark or warm, etc.
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#14 Travis Gray

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Posted 06 July 2012 - 05:46 PM

Probably a dumb question- but I've never been using grey cards before. Decided it'd be a good time to start (separate from reading this thread haha). So just got one in today, and.. uh... it's kinda shiny. I'm guessing it should be matte, yes? Or just not hit direct lights on it, but, shouldn't you be able to stick it somewhere and not have to worry about that?

Not necessarily directed at David haha
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#15 David Mullen ASC

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Posted 06 July 2012 - 08:26 PM

Just make sure it doesn't have a kick or glare across the surface, though all the grey cards I have are matte. Are you sure it is a standard 18% grey card for photography?

Actually I use a grey scale, one that I got from FotoKem or another one from Fuji. Kodak has one that is mostly a grey card but has some small rectangles of black and white on the borders.
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#16 Travis Gray

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Posted 06 July 2012 - 08:40 PM

I was doing a B&H order and just threw this on http://www.bhphotovi...d_Standard.html

I'm guessing this is a you get what you pay for situation haha
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#17 Chris Burke

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Posted 07 July 2012 - 07:01 AM

I was doing a B&H order and just threw this on http://www.bhphotovi...d_Standard.html

I'm guessing this is a you get what you pay for situation haha



Check out Hunt's or Newtonville Camera or EP Levine. They would all have grey cards and grey scales. Talamas and Boston Camera also have them.
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#18 Will Montgomery

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Posted 09 July 2012 - 02:46 PM

Kodak has one that is mostly a grey card but has some small rectangles of black and white on the borders.

Yes, the hand crafted one in the lovely red rubber/plastic envelope. Somehow mine has survived for about 5 years but I'm waiting for the day it gets wet or torn up and I have to shell out another $35 or whatever they want for it these days. It does say Kodak on it.

I actually had a talent start reading the back of it as it was placed in front of her face (how to use this card) at a shoot this weekend and everyone started cracking up.

I've never shot a color chart for the colorist but I've had mixed opinions from them about the usefulness of a color chart. Greycard helpful, but color chart not so important.
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#19 David Mullen ASC

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Posted 09 July 2012 - 03:40 PM

I've never shot a color chart for the colorist but I've had mixed opinions from them about the usefulness of a color chart. Greycard helpful, but color chart not so important.


I think color charts are for testing and grey cards / scales are for dailies, plus testing. If you are testing a stock, a color chart is useful to see how grainy each color chip goes or how accurate the stock is, etc. (but shoot a grey scale or card first to make it easier for the colorist to balance to neutral, though there are small grey squares on the Macbeth chart.)
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