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7207 Color Correction with Color Card/Chips


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#1 LowellMeyer

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Posted 09 February 2011 - 05:30 PM

Hey guys,

I'm shooting a short for my film school on 16mm Kodak 7207 Vision 3 250D and the director has been changing the lighting up for a scene this weekend. Instead of window lighting for a day interior, we are to use lamps to light the scene. This causes a problem for me because we probably won't have access to a 80A filter nor a color temperature meter and I'd rather not go and put CTB gels on all the lights because it might not accurately match the 5500 K color balance of the film stock.

Do you think I would be safe just shooting the film at 250 in tungsten lighting and relying on the kodak color chips we have to get us through the DI process? I know it's better to nail the colors on the negative but I don't know how much range there is in manipulating the colors when we go into the post process so I wanted to reach out to you guys and see what you think.

Let me know ASAP as we start shooting this coming Saturday. Thanks!

Lowell
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#2 Adrian Sierkowski

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Posted 09 February 2011 - 05:39 PM

Personally, I like the look you can get with D film under T lighting. You might want to have DSLR on hand to shoot a preview for the scene so as to know how it's looking but there is a lot of room on that neg for corrections. Also you can put on 1/2 CTB as opposed to full ctb.
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#3 LowellMeyer

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Posted 09 February 2011 - 05:58 PM

Personally, I like the look you can get with D film under T lighting. You might want to have DSLR on hand to shoot a preview for the scene so as to know how it's looking but there is a lot of room on that neg for corrections. Also you can put on 1/2 CTB as opposed to full ctb.


The DSLR idea is a good call. I don't know why that didn't come to mind. I will definitely keep that on hand as a reference, especially when applying any CTB gels to the lights.
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#4 K Borowski

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Posted 09 February 2011 - 06:21 PM

The key is to get adequate exposures on the red, green, and blue layers of daylight balanced film which is roughly proportional in i8ts sensitivity to each. Tungsten film, on the other hand, is more sensitive to red than blue wavelengths of the visible EM spectrum.


So, giving the film extra exposure should give adequate exposure to the blue layer to allow the film to be corrected in telecine without any color noise or grain in the shadows. Good idea using a DSLR. Much easier to use than a color meter. One thing to be aware of: You're using it to gauge exposure, not the way film will render color. Has to do with UV sensitive silver halides, vs. IR sensitive chips. So they don't react to the same colors the same way. Honestly, I'd say digital is a lot worse though with improper color balance, at least the shots I've seen from DSLRs where the camera is set to daylight but shot under tungsten.



But, where are you? You can practically buy a filter at any corner store in NYC. Elsewhere, more difficult, but certainly not impossible. Any major city should have a camera store that can help you. A cheap, low tech, "unprofessional" move you can just hold an incorrectly-sized filter over the lens (assuming of course this is feasible, not a shakey-cam handheld shot). Just don't let any potential future clients see you doing this, and watch out for flare. In a real crunch, you can use a sheet of lighting gelatin. Again, don't get caught doing this if you want others to respect you ;)

80As are harder to find now, but I'm sure there are plenty of camera stores that had them from the film days that want to clear them out. I'd just shell out and buy one.
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#5 Adrian Sierkowski

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Posted 09 February 2011 - 06:25 PM

Problem, IMHO with an 80a is the 2 stop loss from the glass.
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#6 LowellMeyer

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Posted 09 February 2011 - 07:36 PM

Problem, IMHO with an 80a is the 2 stop loss from the glass.


Yeah, that was one of the reasons why I'm not too sure about the 80A. If I use it on 250D, my ISO will be equivalent to 64 and that might be a little tough because we don't have a significant lighting package and we'll be indoors.
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#7 K Borowski

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Posted 09 February 2011 - 08:54 PM

Just underrating the film and correcting in post, won't cost two stops, but you'll still have to drop some speed to avoid color crossover, and severe underxposure of the blue layer.


If speed is an issue, I assume gel-ing the lights at the source will cost you the least amount of exposure with fully-correctable color rendition. Only time I've ever had to shoot daylight stock in tungsten, has been at low frame rates on a tripod.

Usually I carry tungsten, so I don't know the numbers OTOH. Wasn't there a post on here where David Mullen was talking about a partial color correction filter? Or was that also converting tungsten stocks to daylight balance?
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#8 Adrian Sierkowski

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Posted 09 February 2011 - 09:03 PM

I'm pretty sure that was an LLB which is like an 85. I'd shoot w/o correction, rate at 160 ish, or perhaps just 250 if I needed to,and throw 1/2 CTB on the lights if need be. There are of course 1/2 correction filters for the cameras as well, maybe an 80C? You'd have to double check that.
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#9 LowellMeyer

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Posted 09 February 2011 - 10:22 PM

Thanks for the help, guys. I'll probably end up using 1/2 CTB on the lights and underexposing by a stop. The scene takes place during a stormy day anyway so it won't hurt to make the indoor lights a little bit warmer, the outdoor light a little bit colder, and the scene overall a bit darker.
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#10 Adrian Sierkowski

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Posted 09 February 2011 - 11:32 PM

Darker is all well and good, but don't under expose. You'll be fine with just normal lights for INT and 1/2 CTB for "daylight," you can dial it back in post to "normal," if you'd like but under-exposure will hurt your options a bit.
You should have enough light in most locations from most sources to be able to pull out enough light naturally for a 250 stock, and once you augment with some film lighting, or larger wattage practical bulbs you should be a-ok.
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#11 K Borowski

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Posted 10 February 2011 - 06:29 AM

You're mis-reading what I said. . . Don't underexpose, OVER-expose. You need to get the exposure of the BLUE-SENSITIVE LAYER up to a point where the lab can correct the colors on your negative without adding noise or grain to the image.


Just ignoring the problem, exposing as normal, willl yield an over-exposed red layer, a somewhat under-exposed green layer, and an under-exposed blue layer.

Think of it like shooting three films at once: You're shooting a red-sensitive film, a green-sensitive film, and a blue-sensitive film simultaneously. The blue-sensitve and green sensitive films are lower speeds than the red-sensitive.

Got it? ;)


I checked on this last night in my American Cinematographer manual. 80As are actually 2-1/3 stops of light loss, so your 250D will come out at 50T with the correction. I'd shoot a clip test right now to make sure you can get adequate status-M density in your negative's blue channel with the lighting setup you have.

If you don't test, all I can offer are educated guesses. NOT RECOMMENDED.
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#12 LowellMeyer

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Posted 15 February 2011 - 01:57 PM

Mr. Borowski,

Thanks for that correction. Your three different films analogy helped explain the process a lot. However, for the shoot, we ended up eliminating daylight from the interior scene entirely and used kinos and practicals with daylight bulbs instead. I was extremely pleased with the shoot and I'm hoping for some good results when we get the negatives back from the lab.

Lowell
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#13 K Borowski

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Posted 15 February 2011 - 05:21 PM

Lowell:


I hope everything turns out OK for you.


You really ought give Adrian credit too!





Be sure to post your results here, even if just a still frame. Theory is one thing; practice is the point, though. . .
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#14 LowellMeyer

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Posted 15 February 2011 - 09:07 PM

Sorry! Thanks, Adrian!
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#15 Adrian Sierkowski

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Posted 15 February 2011 - 10:29 PM

No need to apologize ;)
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#16 Chris Burke

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Posted 28 April 2011 - 06:59 AM

Mr. Borowski,

Thanks for that correction. Your three different films analogy helped explain the process a lot. However, for the shoot, we ended up eliminating daylight from the interior scene entirely and used kinos and practicals with daylight bulbs instead. I was extremely pleased with the shoot and I'm hoping for some good results when we get the negatives back from the lab.

Lowell



how did it turn out? Any stills or vimeo clips to show us?
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