Using Color Correction Gels with New Digital Cameras

I am sticking to my promise and delivering content that many of you requested in the survey a few months ago on blog topics. This is an interesting one that not many people talk about. It is absolutely one of the most essential tools for a cinematographer. Color correction gels can be used many ways, but what I will discuss is how to use them in subtle ways to create color contrast with the new digital sensors.

“Giving Your Story an Early Morning or Late Afternoon Tone”

When I first became a cinematographer, there were two companies in the gel manufacturing business, Rosco and Lee. A few years later, a new kid on the block emerged, GAM Filters. They had been big on party colors, aka theatrical colors, and jumped into the color correction gel business as well. Back in the day, CTO was the only way to warm your lights up in increments. You had: 1/8, 1/4, 1/2 and Full CTO.

Rosco CTO Gels

In the mid-nineties, Rosco introduced a warming gel called CTS, which had more yellow than orange in it. I prefer yellow over red and orange as a color on skin tones. The CTO line seemed to deliver more red and orange. With the digital sensors, I find that the CTS works the best on skin tones, giving that vitality and golden glow.

When I use HMI lights, they all tend to be a little cold to my eye so I warm them up a little bit to start. Mornings are more calm and clear, which gives you that greener, cleaner look at sunrise. Sunset is a more an orange feel and tone, mainly because all the particles that have been stirred up during the day add a warmer feel. Obviously this is just my personal observation. I prefer to use the best aspect of CTS and CTO and not just one gel for all looks.

Early Morning “Sunrise”

When I lensed this scene in The Greatest Game Ever Played, I used CTS to deliver a more yellow tone, which I felt fit the morning light that we described above, with that green at sunrise.

It is really important to experiment with your color temp meter and watch the sunrise and see what your Kelvin does. Then do the same at sunset. Notice your green levels as well. This is where I came up with the whole thing, baseing decisions on science and observation, not just creative choice. Great lighting is the synergy between Art and Science.

Full and ½ CTS used to deliver the early morning sunlight in Greatest Game.

Full and ½ CTS used to deliver the early morning sunlight in Greatest Game.

The Greatest Game Ever Played

Minolta Color Meter II

Minolta Color Meter II

 

Late Afternoon “Sunset”

When it was time to pull off a late afternoon dinner scene in Greatest Game, I turned to CTO with its little extra orange to deliver the mood and tone. This required me to combine Full CTO and ½ CTO on my 18Ks out the windows. This is where GAM Filters got really inventive. They did gel combos where instead of using Full CTO and 1/2 CTO, they made one gel that did that combo called extra CTO. Better for the environment and cheaper. Now one gel did the work of two. It also helps with heat. When you put two gels together without an air gap, they burn up, plastic to plastic. This costs more money as well because you have to replace more gel, so it is a win win. Save the environment and save production money.

Full and ½ CTO added to HMI’s outside windows to deliver a late afternoon tone.

Full and ½ CTO added to HMIs outside windows to deliver a late afternoon tone.

“Creating the Look and Feel of Warm Practicals”

Using CTS and CTO on tungsten sources is so important. As mentioned previously, I feel most HMIs are a little cold to my eye. I feel the same with tungsten lights. They are too cold, so warming them up a little bit is key.

The Greatest Game Ever Played

“Creating the Look of Sodium Vapor Street Lights”

This has been my mission for years — to find a gel pack that emulates the High Pressure Sodium street lamp, the warm looking one. You can get close, but it never looks totally right. (See a previous post on color temp.) So I engineered these lights to give the exact color. Urban vapor is a match to low sodium lights, which do not exist much anymore because of their power inefficiency. So that one is no good. You can play with it, but I have found that when using the light that you are trying to match, gels can only go so far in matching the Metal Halides and the Sodiums.

400 Watt High Pressure Sodium street lights mixed with the storefronts light Molly’s journey in Swing Vote.

400 Watt High Pressure Sodium street lights mixed with the storefronts light Molly’s journey in Swing Vote.

“Color Correction Gels That Many Never Think Of”

Before Kino Flo existed, (wow I am dating myself) you needed to use a specific gel called minus green. This gel would color correct your cool white flo and take the green out. By doing this, it would also warm up your flo. I remember crews going into office buildings and for days adding minus green gel to all of the fixtures. What a time consuming, inefficient process. Then some manufacturers started to make some flos that were tungsten based, called Optima 32s, and daylight balanced, which were Chroma 50s. You would now send a crew in to change all the bulbs instead of cutting the gel and placing them in the fixtures — still very inefficient.

I am a big fan of using the color of the lights that exist and timing the green out later in post if that is what is best for your story. Maybe you want the scene to be a pea green or a minty green to assist the look, mood and tone of your film. Whatever the case may be, if you want it neutral, then using the same colored bulbs that are in the ceiling and correcting it later is one approach.

“Going About It Another Way”

The other approach is using the beauty of plus green color correction gels to aid your look and feel. How do you do this? Say you are shooting in Walmart. They have seven thousand cool white flos in the ceiling. If you do not have cool white Kino Flos at your disposal, you can use HMI lights with Full Plus Green on them. It gets your light very close. It will not look promising to your eye, but it will look good in the camera.

An HMI is what you want when you are doing any interior store photography with Cool White or Warm White flos. Tungsten units take way too much gel to get them to the color temp of a cool white and then when you get there, you won’t have much output. It will take Full Plus Green and usually 3/4 blue to match a cool white tube, which is usually around 4400 Kelvin. So imagine a tungsten unit being 3200. When you add the Full Plus Green, your color temp drops to 2800 Kelvin and now you have to cool the light to reach 4400. If you are matching a Warm White flo with a tungsten light, this will require Full Plus Green, which lowers your Kelvin to 2800, then 1/4 and 1/8 CTB, which is Blue gel, to get you to the 3400 Kelvin.

Tungsten to Cool White Using Gels

14 Comments
  1. Greg Greenhaw 2 years ago

    Don’t you get the cleanest image on digital cameras with a more blue light since the blue channel tends to be the noisiest? If that is true would it be better to light scenes with a more white/colder light then adjust in post?

    • Author
      Shane 2 years ago

      Greg Greenhaw, I never use 3200 Kelvin on any digital camera. I am always around 3700 or 4000 Kelvin when I am lighting a scene with tungsten light. Blue channel is the noisiest on the Alexa, RED and Sony. But on the Canon side of it all the blue is not as bad as the others.

      • Greg Greenhaw 2 years ago

        Thanks for the reply Shane.

        Would you ever use daylight on a scene that was intended to look warm just to optimize the channel information?

        I heard you can not trust a color meter on led lights. Whats you opinion?

        On a side note have you messed around with raw video on the mark III? If so whats you opinion?

        • Author
          Shane 2 years ago

          Greg Greenhaw,no, I will slide the color temp to get a little closer, but that is a bunch of bullshit.Yes, that is true that you cannot trust a color temp, I simply have the camera on and add the gels to make it look the very best based on the sensor that you are using. No I haven’t used it much. Just played with it on Need for Speed when it first came out, but to function with a team of many shooters it is a camera protocol that I don’t want to inject in my workflow right now.

  2. Andrew Takeuchi 2 years ago

    Great article!

    I’m curious about the CRI of those AAdyntech JAB LED’s – the specs for photometrics and power draw look impressive but their website doesn’t offer much info about the CRI of these units. Any thoughts?

    • Author
      Shane 2 years ago

      Andrew Takeuchi, they were amazing and with a little 1/4 minus green we were able to get them right in the ball park with the C500. Their output was impressive. All on a battery.

  3. Alex Disenhof 2 years ago

    I recently shot a Somali Pirate movie in Kenya. We shot aboard a large oil tanker whose interior was lit entirely by 2′ T8 cool white floros mixed with natural daylight. We didn’t have the resources in Kenya to change everything to kinoflos, so I had my guys gel about 200 lights with 1/4 minus green. A pain in the butt, but worked like a charm! I also found myself using CTS all the time at night. It was really beautiful on the darker Somali skin tones.

    • Author
      Shane 2 years ago

      Alex Disenhof, thank you for sharing, that sounds perfect. I love that CTS on Darker skin tones.

  4. Marco 2 years ago

    I really like to gel HMIs with a 1/4 CTO. I think it brings the life back to a very sterile light. Yeah, it’s pretty basic, but I know people who never tried this before.

    I also like to use 1/4 CTB on peppers, when I bring in an array of them as a key light, which I like more on most skintones.

    With cameras up to ASA2000 LED, Flos etc. are more important than ever, so is using the right gel.

  5. Edward Smyła 2 years ago

    Dear Shane,
    Thank you for the great post on light. Could you please say more about you “never using 3200 Kelvin on any digital camera” when lighting a scene with tungsten light. Do you go up in Kelvin also when you apply CTO/CTS to your tungsten light?

    • Author
      Shane 2 years ago

      Edward Smyła, I don’t like the feel of 3200 degree, for some reason I feel it is a forced color. So 3400 or 3700 feel better to me. Yes I go to these color temps even with the CTO and CTS are on added to the lights. But again it all depends on your scene. If you want a neutral look then I would not add the color. If you want a warm inviting feel then yes.

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