Set Consistent Looks and Match Your Cameras As You Shoot Source: Studio Monthly
Modern cameras make great pictures right out of the box, right? That’s often true, but accurate alignment to a precision Color Calibration Chart is essential to achieve a consistent “look” and quality standard.
In our professional life as videoraphers and filmmakers, we need to be able to agree on color. To do this we need a point of reference and to have a series of colors laid out in a consistent fashion to be able to determine colors and assign a name and value to a representation of that color. In the business of creating images, color is everything.
Making grading decisions with the naked eye is risky business, requiring both a perfectly calibrated monitor and the proverbial golden eyeball. This should rule out eye-balling color correction and scene-to-scene matching on your laptop. However, with a DSC chart, and color and waveform data to complement your NLE, you can make intelligent grading decisions even on a laptop.
Using a Color Calibration Chart also helps you make a number of other time-saving choices, including the following.
Matching Multiple Cameras
Camera matching becomes impossible without an accurate test pattern or analytical tools. No two cameras are identical, which makes it unreliable to upload the settings from one camera to another. The only way to match cameras effectively is to adjust the matrix settings of each camera using the same precision test chart under the identical lighting condition.
Adjusting Cameras During Production
Check and adjust cameras on the fly, and immediately see the effect of any hue changes on surrounding colors. When producing greenscreen and other digital special effects, Color Calibration charts provide precise information about how camera hue adjustments are affecting the full gamut of color reproduction. Image quality and consistency can be enhanced by recording chart information to tape or film, and using it in post as a baseline production reference. For scene-to-scene consistency, record a few chart frames with every lighting change. You’ll expedite any color-correcting, matching footage, and digital/special effects you need to do in post.
Keep in mind that every time you recalibrate or re-time your shot in post, you’re decreasing your signal’s inherent quality. You’re throwing away data that it needs. Today’s DPs and digital/special effects technicians increasingly view DSC charts as necessities for optimizing their high performance cameras, and the production value of their images.
I had the pleasure of testing DSC Labs CamAlign CDM 28R Chroma DuMonde Color Calibration Chart, the latest addition to DSC’s family of production-friendly CamAligns. These are high-performance charts with at least 12 precise colors and are made to the latest SMPTE 274M international colorimetry. Whether used in production or in post, these charts generate precise hexagonal-shaped displays for HD, SD and NTSC television images.
While every DP has his/her own technique for aligning a camera, they will typically use the procedure I tested. Testing with a Panasonic AG-AF100, I focused and framed it on the evenly lit CamAlign CDM 28R. I set the Iris mid-scale; the exposure/iris is adjusted to set the white chip of the DSC grayscale to 700mv. You should also check the tracking of RGB channels to ensure neutral reproduction across the grayscale. White and black balances are then set. Because all DSC colors combine to produce a neutral color balance, most cameras will white balance on a DSC color chart as accurately as it will on a TrueWhite card.
The Chart I was sent included pattern with the DSC Labs Cavity Black, for the ultimate black reference tool. Attached to the back of any CDM pattern, the CaviBlack folds out for use and then folds flat for convenient storage.
The charts from DSC Labs are manufactured to stringent color fidelity standards. Sometimes only one in 16 charts they print meet the rigid technical specifications they set for color. The narrow tolerances of DSC charts give users a higher level of confidence in knowing that placing color signals in the boxes should result in accurate color reproduction.
Recording a few seconds of a DSC test pattern on the set, at the head or tail of a scene, captures virtually everything a colorist needs to know to color correct or match scenes. Secondary colors from a DSC ChromaDuMonde pattern are especially useful when shot on set as they enable changes in lighting or exposure to be corrected in post with speed and efficiency.
In my opinion, CamAlign is the perfect accessory for the serious videographer. Careful adherence to a common set of calibrated references is critical for maintaining image quality on any HD project.