If you are producing online videos like myself, your audience will watch your creations on a large variety of different devices. All of these devices have different displays, each with their own unique nuances in representing colour. This means that the very same video may look a little bit too blue or too purple, too bright or too dark for some users.
You cannot control how the screens display your video and what colour imperfections they may introduce, but if you ensure that your video is properly colour corrected, chances are it will look good for almost anyone who watches it. But how do you know that your own monitor isn't "lying" to you? How do you know if the video is in fact properly colour corrected?
For this, you can use some of the advanced tools available in Adobe Premiere Pro like the Waveform Monitor, the RGB Parade and the Vectorscope to analyse the colour information in your video and make adjustments with much more accuracy.
The waveform monitor displays the brightness (luma) information in your image. It represents your video from left to right, just like in your preview window, and distributes all pixels vertically on a scale from 0 to 100. Any pixels that lie on the 0 line are absolute black and any pixels that fall onto the 100 line are absolute white.
Here is an example video I took on Philip Island in Australia. In the waveform monitor you can see a few pixels clipping at 100, representing the tips of the waves. You can also see a prominent band of bright pixels spread across the image from left to right, which is our sky.
Ideally, you want your image to contain pixels across the entire spectrum from 0 to 100. This way you are utilising the entire dynamic range available to you. In our Philip Island video, we can clearly see that there is a gap at the bottom of the waveform monitor. We do not have a lot of dark tones in our image and it is lacking a little bit of contrast.
To fix this problem we can apply a Curves effect and make the dark colours a little bit darker. For this, we push the bottom left corner of the Master (luma) curve to the right. I also decided to brighten my image up a little bit more as there was a lot of space above the sky and I didn't mind the tip of the waves clipping a little bit. I did this by pushing the top right corner of the Master curve towards the left a little bit.
Our final image is now properly exposed and spans the entire spectrum on the waveform monitor from 0 to 100.
The RGB parade is similar to the waveform monitor in that it displays the brightness values of your pixels in your image, spread out left to right. The RGB Parade however contains 3 separate waveforms, one for each colour channel.
The RGB parade makes it easy to see how strongly particular colours are present in your image. It is great for revealing where certain colours may be represented overly strong, causing colour tints.
In the following image, the red and blue channel are clearly stronger than the green, introducing a bit of a magenta colour tint to the video.
It is important to note that having one channel stronger than another doesn't necessarily mean that your footage has an unwanted colour tint. Your image may simple be a very red image, e.g. a sunset or a fire. Use your judgement when looking at the RGB parade and compare it to what you would expect to see from the image.
One of the best tools in Adobe Premiere Pro to show you the colour distribution of your video is the vectorscope. The vectorscope is a colour wheel with 6 colour markers for red, magenta, blue, cyan, green and yellow. In the centre you will see a point cloud showing the colour distribution of the pixels in your image. The further the pixels are away from the centre of the vectorscope, the more saturated they are. If you are viewing a greyscale image through a Vectorscope, all pixels would lie in the exact centre as they would have no colour whatsoever.
The border that connects the 6 colour markers in the vectorscope defines the broadcast safe colour range. If your pixels lie outside of this area, the colours may not be represented accurately when your video is broadcast. If that happens, reduce the saturation or adjust the colours of your video to bring the pixels back into the broadcast safe area
Now that you know how to read these tools, let's use them to colour correct our video.