Rangefinder Magazine
December 2001/Features

The 10 Facts of Life About Color Correction, Part lll by Will Crockett

No matter if you shoot digital capture, color negative, or color transparency films like me, you will see a major refinement in your color reproduction capabilities after you discover the…

Fact #8 – Know where your film’s Neutral Rendering Point is
All modern daylight transparency films are supposed to give you neutral (not too warm, not too cool...) colors when you expose the films with light that has a color temp of 5500K, right? Wrong.

The working NRP is effected by other factors as well like film processing variances, the care and storage of the film prior to processing (this is why we, like most true professionals, never use gray market films), and the coloration of your camera’s lenses too.

NRP’s for digital capture systems revolve around an accurate white balance. This is a feature of most good quality camera systems that allows you to place a white card (foam core panels work great!) or a color checker chart in front of the lens to fill the entire frame. Then in the “white balance” or “calibrate” mode you make a test exposure or two to determine what the camera and your lighting set up considers “white” or neutral. This sets the camera right on it’s NRP. If you’re serious about digital capture quality, be sure to get into a system that has a calibration function.

The images on page 30 are examples of the importance of observing the Neutral Rendering Point:

Film: Fuji Astia 100 Will’s NRP: 5150K Exposure Color Temp Used: 5150K Result: Neutral tones	Film: Fuji Astia 100 Will’s NRP: 5150K Exposure Color Temp Used: 5600K Result: Cool tones

Fact #9 – Filters are precise, gels are not

We refer to filters and gels as two different tools. Filters are optical grade plastic or glass that goes in front of (or sometimes behind) your lens. Gels are non-optical grade plastic sheets that go in or on your light source. Gels can take the heat from your lights, filters cannot. There are many, many different types of filters but for color correction purposes we are concerned only with ones that control color temperature, (LB filters) and ones that control color balance (CC filters).

Filters that alter color temperature are archaically referred to as “LB” or Light Balancing filters when they really don’t “balance” anything. They just shift the color temp (warm/cool) up or down in varying amounts. Think of color temp filters like the 80, 81, 82 and 85 series as grabbing a hold of all the ROYGBIV color in your shot and raising or lowering all the color at one time in a precise amount. They don’t change any one color in particular, they shift them all up in color temp or down in color temp without disturbing the delicate balance between the red green and blue components of the light.

CC filters do just the opposite. They will adjust only the narrow red, green or blue components of your shot without disturbing the overall color balance. For data on what each LB or CC filter does, refer to the manufacturer for a booklet or chart.

Gels on the other hand also are used to adjust your light source ‘s color temperature or color balance, but they are not so precise. For color temp adjustments CTO or Color Temperature Orange gels will shift your light source’s color temp down making it more warm/ amber, and CTB or Color Temperature Blue gels will shift your light source’s color temp up, making it more cool/blue-ish. CT series gels will not affect color balance at all—only color temperature. Here’s a look at what common CT gels actually do:

CC or Color Compensation gels will allow you to adjust color balance, but they also have a nasty side effect of lowering the color temperature too. This gets a little complicated so if you would like more data and info regarding CC gels, please view or download the Conquering Color Correction Guide v 3.2. located in the InfoCenter section of our www.shootSMARTER.com website.

Fact #10 – If you’re not sure, schedule a pre-shoot to test

If you take a look at the set you are working on and you see a source you are not too sure about, take a measurement with the color meter as it may point you in the right direction. If the meter is unclear, or reads in substantially different values with each measurement, you may need to schedule a pre-shoot. Go in a few days before (if possible) and shoot the same film/camera/lens combination you will be shooting the job with and make careful note on which frames you made no filtration, and which frames you added some filtration and it’s corresponding filter compensation. Clients may appreciate your attention to detail and prep. You also may want to let clients know (in writing) that if it’s impossible to pre-shoot in their environment, there may be difficulties in delivering a perfectly corrected trans set.

If your client requires only a print instead of a high-end digital file, you can shoot a few color negative films that will automatically remove the green shift caused by fluorescence without having any bad side effect on the true greens like grass and my former assistant’s teeth. Fuji’s patented “fourth dye layer” technology does just that and works very well in most situations. Please contact your dealer or Fujifilm rep for more details.

Will Crockett is an award winning commercial photographer and considered one of the country’s top seminar presenters and photo educators. Based in suburban Chicago, Will has an impressive client list that spans the globe to include DaimlerChrysler, United Airlines, Sears, ABC Network Television, and Boeing just to name a few. You can learn more about Will and his work at www.shootSMARTER.com.