Image Credit: Anna McKee, Internal Tutorial followed: “Colour Correcting with the Grade Node”

File Formats and Codecs

• File Format - This determines how information is stored as a file

  • There are many different types of file format, some are more preferable for editing, storing or sharing

• Codec - Compresses data, which enables faster transmission. It then can decompress the received data

  • Applications use Codecs to write and read the file

  • (Coder-Decoder / Compression-Decompression)

  • Codecs are software that help to ‘Encode’ a range of media files, such as images, audio, and video

  • Two types of Codecs: Lossless and Lossy

  • Examples: MP3, WAV, H.264, H.265, TIFF, RAW

• Container - Also known as the ‘Format’

  • Examples of Containers: MOV, MP4, DNG, TIFF, OPEN EXR, TGA, Quicktime, etc

  • Quality of container will be determined by the choice of Codec

Image Credits: PortalDekave, Wikipedia, FreebieSupply

• Lossless Compression - Compresses the file to a smaller size, when reopened the media will have retained all of its detail

  • Result file when opened is the same size as the original

  • No quality loss

  • Examples: PNG, WebP, GZIP, DPX, Open EXR, etc

• Lossy Compression - File is compressed, although the quality has been permanently altered

  • Result file is smaller than the original

  • Irreversible compression method

  • Quality has been lost

  • Examples: JPG, GIF, MPEG Video, MP3 Audio, etc

• Bitrate - Upload + Download speeds

  • Measured in ‘bits per second’

  • The faster the Bitrate, the higher the quality of media, although this results in a bigger file size

• JPG - Most suitable for photographs

  • Ideal for sharing and storing digital images, due to their high compression rate.

  • Form of Lossy compression

• PNG, TIFF - Suitable for displaying complex images

  • PNGs better for online websites

  • TIFFs are suited for scanning and print

  • Form of Lossless compression

• HDR - "High Dynamic Range”, the contrast between the brightest and darkest parts of an image. (12+ Bit channel)

• Open EXR - Raster format, high-dynamic-range image file format. (Uses a 32 Bit channel)

• Log Footage - “Logarithmic footage”, compressed / flat footage that contains a greater amount of detail

  • Not meant to be used without post-production editing software, such as Nuke

  • Used for extensive Colour Grading

• RAW Footage - Created with the camera’s sensor, colour will look flat / dull before post-process editing has begun

  • Post-production workflow is required to view this footage

  • Creates large file sizes

Image Credits: GISGeography, Riverside, Albion, Wondershare

• .ma Maya ASCII - Maya File, backwards compatible

  • More reliable, as if the file becomes corrupted, the file might be saved, (scripts can be ran in an attempt to make the file reusable)

• .mb Maya Binary - Smaller file size

  • Less reliable, as if the file becomes corrupted, it is ‘unsavable’

  • File is saved as numbers

• .fbx - Fast, efficient, written in Binary format

  • Highly compatible

  • Allows for storage of textures, colours, lighting and other artefacts

  • Commonly used when moving 3d models from programme to programme

• .tx - Native image format for Arnold

  • Using .tx files will help speed up render times as they will utilise texture cache

• Open EXR - Support multiple image layers

  • Most commonly used when creating visual effects in compositing software

  • Allows for use of AOVs, this is especially important when exporting from Maya to Nuke

  • Allows for.fine-tuning / control of Specular, diffuse, AO, Alpha layer, lighting, s.s.s, transmission, depth of field, motion blur

  • It is better to export as an EXR from Maya to Nuke, as this will allow the compositor to use the render layers to make subtle / major adjustments within their own viewport

Image Credits: Autodesk Arnold, Darryl Dias

Online Further Reading -

Audio Codecs Explained - Audioholics

Lossless Compression vs Lossy Compression - GISGeography

What is video bitrate: The Full guide - Restream | Blog

.tx information - Arnold Support Corner

AOVs - Arnold for Maya - Autodesk Arnold

Nuke Fundamentals - Internal Tutorials

Colour Correcting with the Grade Node

Image credit: Colour correction created by Anna McKee, Original painting by Vincent van Gogh, Internal tutorial created by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 5/10

01/02/2023 -

The goal of this Internal Tutorial was to Colour Correct the image provided of the “Sunflowers” painting, as the original photograph was quite dark and desaturated.

Following the tutorial, we were instructed how to use professional Colour Correction techniques (including a Blur node) within NukeX and how these tools could be continuously reused for the a similar visual purpose.

Topics covered within this live Internal Tutorial:

• Reformat Node - Used to change the resolution size of the input image

• Color Grade Node - Used to ‘colour pick’ the lightest + darkest pixels within the image. Also used to supply the main relief of colour correction within the editing/compositing process

• Curve Line - Used to create a ‘frame’ around the painting, separating it from the wall. This allowed for greater control when colour correcting the wall and painting as different entities

• Blur Node - Utilised to ‘blur’ the white background wall of the painting, as this helps to sustain more focus on the painting itself

Credit: Screenshot Anna McKee

Nuke Fundamentals - Internal Tutorials

Colour Correction, Matching Shots: Grade Node, Part 1

Credit: Anna McKee

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 6/10

02/02/2023 -

Within this Internal tutorial, “Colour Correction, Matching Shots: Grade Node, Part 1”, the process of using a Grade Node to Colour Match was explained.

Credit: Screenshot Anna McKee

Nuke Fundamentals - Internal Tutorials

Colour Correction, Matching Shots: Grade Node, Part 2

Image credit: Colour corrections created by Anna McKee, Internal tutorial created by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 5/10

02/02/2023 -

This Internal Tutorial, “Colour Correction, Matching Shots: Grade Node, Part 2” consisted of 2 main parts.

Firstly we were guided how to Colour Match within NukeX, while using a simplistic “Patch” Image. My final result of this process was slightly unsuccessful, due to the purple square not being sufficiently ‘colour matched’.

Although this attempt was deemed a failure, I decided to continue with the tutorial and push myself to succeed within the second-half of the video, (this involved colour matching images of a Diner).

Continuing through the tutorial, I began to grasp a stronger understanding for the importance and use of the “Color Grade” Node, (including the process of utilising the Eyedropper Tool and keys: ‘Command, Option and Shift’).

Colour Grade Hotkeys for Mac -

• Command + Left Mouse Button: Color picker (single pixel)

• Command + Right Mouse Button: Deselect sampled pixels

• Command + Shift + Left Mouse Button: Color picker (region of pixels)

Patch Colour Correct

Credit: Screenshot Anna McKee

Diner Colour Correct

Credit: Screenshots Anna McKee

Nuke Fundamentals - Internal Tutorials

Colour Correction, Matching Shots: Grade Node, Part 3

Image credit: Colour correction created by Anna McKee, Internal tutorial created by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 3/10

02/02/2023 -

The purpose of this simple tutorial was to Colour correct the “Reference Image” to the Matching Image” featuring Stonehenge.

This was an extremely enjoyable process, which helped me to grasp basic concepts of using the Eyedropper Tool to select ‘White Points’ and ‘Dark Points’ within each sampled image. After this, the process then moved along to selecting pixels from the ‘Lift’ and ‘gain’, which also helped to add a stronger sense of colour match when adjusting the sliders of the colour wheel.

The next step included making slight adjustments within the colour wheel, whilst also studying the individual Red, Green and Blue channels to create an almost ‘perfect’ colour correction.

Credit: Screenshots Anna McKee

Credit: Screenshots Anna McKee, Internal Tutorial provided by Kingston University

Nuke Fundamentals - Internal Tutorials

Alpha Channel Part 1

Credit: Screenshots Anna McKee, Internal Tutorial provided by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 4/10

03/02/2023 -

Within this Internal Tutorial, “Alpha Channel Part 1”, the concepts and purposes of an ‘Alpha Channel’ were discussed, along with the procedures necessary to add an ‘Alpha Channel’ to an already existing image.

Using the example of the leaf, we were shown how to add a separate Alpha Channel from a .jpg image, onto the original .jpg image. This included using processes such as the ‘Shuffle Node, Premult Node, Transform Node’ (including the optional nodes: Constant Node and Merge Node’, which were used to add the bright green background).

When following-along the Coffee Cup tutorial within the “Alpha Channel Part 1” video, we were shown a quick and simple example of how to check if a .png has an Alpha Channel available. The simple process of adding a Constant Node to create a background was also discussed.

Leaf

Credit: Screenshots Anna McKee

Coffee Cup

Credit: Screenshots Anna McKee

Nuke Fundamentals - Internal Tutorials

(Un)Premultiplying for Color Correction - Part 2

Credit: Screenshots Anna McKee, Internal Tutorial provided by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 5/10

03/02/2023 -

During this Colour Correction Internal Tutorial, the topic of editing colours within an .exr along with a ‘Backplate’ was discussed.

The goal of this video was to correctly Colour Correct the .exr Helicopter CG file, whilst also leaving the ‘Backplate’ (background footage, .jpg) unaffected by the Colour Correction.

This was a fantastic tutorial as it explained the important adjustments that must be made when Colour Correcting an .exr, for example:

1. Below the .exr node, a Unpremult Node must be added

2. Below this, a Colour Grade Node can now be added

3. Directly below, a Premult Node is now added

4. This final Premult Node can now be directed into a Merge Node (following through the ‘A arrow’)

5. This Merge Node has a ‘B arrow’, which is also connected to the Backplate

6. The output of the Merge Node is now connected to the Viewer Node

In conclusion:

The reason why we need to go through all of these steps shown above, is because within an .exr, the RGB (Red, green, Blue) and Alpha channels are already mixed = multiplied together.

This means that if we try to adjust the Colours within a “Colour Grade Node” below an .exr, the entire Backplate image colour will be disrupted as a result. This issue can only be resolved by applying an Unpremult + Premult Node, before and after the Colour Grade Node.

After this process, you will now be able to successfully Colour Correct the .exr, along with utilising the Eyedropper tool to colour pick your desired White Points, Blackpoints, etc.

Credit: Screenshots Anna McKee

Nuke Fundamentals - Internal Tutorials

Color Grading a Shot (Log Color Profile)

Credit: Screenshots Anna McKee, Internal Tutorial provided by Kingston University

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 6/10

04/02/2023 -

Within this tutorial, we were guided how to use a professional Colour Grading technique by utilising a Colour Chart within an .mov.

Steps taken to Colour Grade the ‘Cooler Tones’ .mov:

1. Black points and White Points were selected via the Colour Chart. This information was stored within the “Grade 1” Node

2. Connected the selected .mov into the Grade 1 Node

3. Further Grade Nodes have been added to Colour Grade specific channels related to the .mov, eg, adjusting the saturation, gamma, midtones and gain

4. The final “Cooler Tones” .mov provides a ‘bleak’ visual atmosphere, due to its dependance on blues and darker colours

Using the Colour Chart to Colour Grade an .mov - Cooler tones

Credit: Screenshots Anna McKee

Steps taken to Colour Grade the ‘Warmer Tones’ .mov:

1. (The same Node Tree has been used to begin this new Colour Grading process)

   • Although "Secondary CC" nodes have been moved and further Colour Grade Nodes have been connected below

2. .mov is Colour Graded utilizing the Colour Wheels connected to the Gain, Saturation, Midtones and Highlights

3. A simple Bezier Curve box has been added around the graffiti wall above the gate - This allows for specific sections of the .mov to be edited in a different manner.

   • Within this example I have desaturated the wall slightly, as this will draw the viewer’s attention towards the bright Red within the gate

4. A final “Radial Node’ has been added to the foreground of the .mov (the ground)

   • This creates a ‘spotlight’ effect on the ground

5. The final result of the “Warmer Tones” .mov is an image that presents a much more ‘lively’ and entertaining presence to the viewer, especially when compared to the previous “Cooler Tones” .mov

Colour Grading an .mov using a Bezier Curve and a Radial Node - Warmer tones

Credit: Screenshots Anna McKee

Final comparison between the two Colour Graded .movs

Credit: Screenshots Anna McKee

2D Matchmoving - Internal Tutorials

Planar Tracker Workshop

Click on video below to play sequence

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 7/10

08/02/2023 -

The goal of this tutorial was to place two pieces of Graffiti onto an image series of a wall.

This created a necessity for the images to be ‘tracked’ with a 2D Planar Tracking technique, allowing them to sit directly on top of a wall, whilst the camera angle was moving.

TIP - When using a “read” Node, make sure to type “filename.###.jpg” OR “filename.###.mov”, (or however you want your filetype to be)

Press “R” to add an image sequence or movie file.

Credit: Screenshots Anna McKee

2D Matchmoving - Internal Tutorials

RotoPaint Workshop

Click on video below to play sequence

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 6/10

16/02/2023 -

How to use a Track node:

1. Add footage using a “Read” Node (Press R) > Connect to viewer

2. Add “Tracker” Node > Connect to Read Node

3. Adjust resolution if needed to match read footage

4. Click on Tracker node > Transform > Set to current frame (this is your reference frame)

5. Tracker > Add Track

6. Adjust Track in viewport to match area you want tracked > Select a different frame and continue adjusting the Track

7. Press “Track to End” > Select the traffic lights (Show error on track)

8. Adjust any Track issues within the frames > Track to End > Continue adjusting / fixing the Track until the orange / red icons disappears

9. One track has been completed, go back to your reference frame > select track node > Tracker > turn off track (untick box)

Credit: Screenshots Anna McKee

2D Matchmoving - Internal Tutorials

WallE Matchmoving Workshop

Click on video below to play sequence

Credit: Compositing by Anna McKee. Materials, Footage and Internal tutorial provided by Kingston University.

Tutorial: Completed

Software used: NukeX

Personal Difficulty Level: 8/10

17/02/2023 -

The goal of this tutorial was to utilise 2D matchmoving / compositing techniques to edit ‘WallE’ and a rock within the designated table footage.

Topics / Nodes used when compositing The “WallE Matchmoving Workshop”:

• Roto Painting

• Lense Distortion

• Colour Grading

• Premult, Unpremult

• Colour Grading

• 2D Matchmoving

Screenshot Credit: Anna McKee