Color correction refers to the process of adjusting the colors in an image or video to achieve a desired visual look. It is an important stage in post-production and can make a huge difference to the final output. The goal of color correction is to ensure colors are accurate, consistent and match the intended creative vision. There are several steps involved in properly color correcting footage.
Understanding the starting point
Before beginning color correction, it’s important to understand the starting point of your footage. Footage is captured using cameras that apply certain processes to the raw sensor data to convert it into viewable images. This includes settings like white balance, sharpening, contrast, saturation and compression. The combined effect of all these settings gives your footage its “look” straight out of camera. Different cameras will apply this processing differently, so footage shot on different cameras will often look quite distinct.
It’s useful to have an experienced colorist look over your raw footage to understand these original settings and “look”. Are the colors skewed too warm or cool? Is the contrast too high or low? Is there excessive noise or compression artifacts? Diagnosing the footage will help guide the correction process.
Create a base grade
The next step is to apply a “base grade” to normalize the footage. This grade balances out uneven colors and lighting, so the footage looks more consistent from shot to shot. The colorist will examine technical parameters like the black point, white point and gamma curve, and make adjustments to bring them into an acceptable range. They may also address color casts, uneven exposure or clipping issues.
This base grade creates a more standardized, neutral starting point. With the technical issues addressed, the creative grading can begin.
Establish a look
Now the colorist can focus on establishing the desired visual aesthetic. This is where the “look” is created through techniques like:
- Adjusting color balance for warm or cool tones
- Increasing or decreasing saturation
- Boosting or suppressing contrast
- Darkening or brightening the image
- Crushing or expanding dynamic range
- Adding stylized color grades like teal/orange
The look might be tailored to match the story’s genre and mood. For example, a happy comedy may have bright, poppy colors while a moody thriller will have desaturated, gritty tones. Fashion and commercial projects usually aim for bright, vivid colors. The possibilities are endless!
Use scopes
As the grade develops, the colorist will rely on scopes like waveforms and vectorscopes to objectively analyze and measure the colors. These scopes provide information like luminance levels, saturation ranges, skin tones and much more. By constantly cross-checking the scopes, the colorist can achieve precise, controlled results.
Grade for different conditions
It’s important to grade footage for the conditions in which it will be viewed. A film graded for a dark theater will look much too dark on a mobile phone screen. Some key viewing conditions to take into account include:
- Theaters
- Televisions
- Computer displays
- Mobile devices
- Projectors
Ideally, the colorist will grade the footage on certified reference monitors designed to emulate these different environments. They can create multiple versions called “trim passes” optimized for different conditions. Deliverables are supplied for each pass.
Check on multiple displays
Regardless, it’s critical to always check the graded footage on multiple types of displays. A grade that looks perfect on an expensive OLED monitor may look awful on an average living room TV. Testing across devices like tablets, phones, computer screens, TVs and projectors allows the colorist to find issues and refine the grade for real-world conditions.
Evaluate in context
Color correction is not performed in isolation – the grade needs to cut seamlessly with the existing footage. The colorist will constantly evaluate the grade in the proper editorial context – how the shots cut together sequentially and how they intercut with other scenes temporally. Subtle adjustments may be required to achieve seamless continuity and transitions.
Communicate with stakeholders
Throughout the process, it’s vital for the colorist to communicate with creative stakeholders like the DP, director and producer. The client may provide reference images or clips to match, or verbal descriptions of the desired look. Periodic review sessions allow the client to assess shots in context and provide feedback to help hone the grade.
Rendering and deliverables
After the final grade is approved, the colorist will render out master files in the required formats. This may include:
- Digital Cinema Package (DCP) for theatrical
- ProRes or DNxHD master files
- H.264 or HEVC files for streaming/web
- DV deliverables
Additional rendered elements like keys, alphas and mattes may also be delivered. The final files are QC checked one last time before delivery to make sure they match client specifications and expectations.
Creative and technical process
As we’ve explored, color correction involves both creative and technical processes. On the creative side, the colorist works with the director and DP to achieve the desired aesthetic look. On the technical side, the colorist must flawlessly manage color science, scopes, monitoring, workflows and rendering. An expert colorist blends these creative and technical skills to satisfy both the artistry of directors and the critical requirements of distributors.
Primary vs secondary correction
There are two main stages of color correction – primary and secondary. Primary correction adjusts the overall image globally. This establishes the base grade and overall look. Secondary correction makes targeted adjustments to specific parts of the image, like creating masks to separately adjust a face or the sky. Secondary work is more precise and time-consuming.
Tools for color correction
Color correction is performed with professional color grading software such as:
- DaVinci Resolve
- Adobe SpeedGrade
- Apple Color
- Assimilate Scratch
- Autodesk Flame
- Blackmagic Design Fusion
These provide specialized toolsets for detailed primary and secondary grading, tracking, masking, keying and more. Using nodes, layers and advanced algorithms, colorists can finely manipulate aspects like hue, saturation, luminance, contrast and much more. This level of control is essential for high-end color correction.
How is color correction different from color grading?
Color correction and color grading are very closely related terms, sometimes used interchangeably in post-production. However, there are some key differences:
- Color correction fixes technical issues with the footage – exposure, white balance, continuity problems, etc.
- Color grading creatively enhances the footage to achieve the desired stylized look.
- Color correction comes first, establishing a baseline. Color grading comes next to add creative impact.
- Color correction is objective and technical. Color grading is subjective and artistic.
Essentially, color correction is a prerequisite to prepare the footage before creative color grading can begin. But in practice, colorists often shift fluidly between technical and creative adjustments to refine the image.
When is color correction used?
Color correction is an integral process for virtually all video content. It is essential for:
- Movies and television – Dramatic films, sitcoms, commercials
- Broadcast television – News, sports, reality shows
- Music videos
- Documentaries
- Wedding, event and corporate videos
- Online video – YouTube, TikTok, ads, social media
- Video game cinematics
Any type of moving image media will benefit from professional color correction prior to delivery to audiences. The only exceptions are live events or surveillance video where real-time broadcast is required.
Who performs color correction?
Color correction is performed by trained specialists called colorists. Becoming an expert colorist requires extensive training, technical knowledge and creative skill. The role of the colorist includes:
- Analyzing the technical quality of camera-original footage
- Applying corrections to normalize issues
- Collaborating with creatives on the desired look
- Manipulating color grading software to achieve the vision
- Cross-checking scopes and vectorscopes
- Reviewing the grade with the client
- Rendering and delivering final master files
Color correction has become such a specialized niche that most productions hire experienced colorists and grading facilities rather than attempting the process internally.
Typical color correction workflow
A typical color correction workflow goes like this:
- Receive raw camera footage and organize
- Create proxies or low-res copies for grading
- Analyze overall footage quality and problems
- Apply base grade to standardize and normalize
- Discuss desired look with creatives
- Perform primary grading pass
- Refine grade with secondary adjustments
- Render out multiple trim passes for different mediums
- Client reviews grade in context and provides feedback
- Further refinements if required
- Render master files and deliver
This workflow allows the colorist to methodically work through the footage shot-by-shot, ensuring a cohesive final product that matches the creative vision.
Key tips for effective color correction
Here are some key tips for achieving the best results with color correction:
- Shoot test footage first to diagnose any camera issues
- Use controlled lighting when filming to reduce problems
- Record test charts to help neutralize uneven colored lighting
- Match cameras when possible for consistent footage
- Communicate desired look clearly to the colorist
- Provide high quality reference images or clips
- Review graded shots in proper context
- Cross-check colors on multiple displays
- Allow sufficient time and budget for the process
Why is color correction so important?
Color has an enormous impact on the look, feel and quality of video content. Poorly corrected footage can look amateurish, dated or visually displeasing. Audiences respond emotionally and subconsciously to color and exposure. Effective color correction ensures media looks its absolute best by:
- Creating properly exposed, naturalistic images
- Generating a unified, consistent visual style
- Establishing the appropriate mood via color palette
- Drawing the viewer’s eyes to points of interest
- Matching brands’ specific color signatures
- Meeting technical requirements for broadcast
- Compensating for environmental viewing conditions
For all these reasons, color correction done right is a critical post-production process that finishes the visual presentation of professional film, video and photography.
Conclusion
In summary, color correction is the crucial process of adjusting footage to consistent technical standards and aligning it with the intended creative aesthetic. Adept color correction requires specialized software, monitoring, technical skills and artistic sensibilities. But the time and expense is well worth it. Proper color correction makes all the difference in crafting engaging, professional media that connects with audiences and brings creative visions to life.
