Overview
One possibility for live grading on set is accessing and changing an image directly in the camera. However, workflows for in-camera grading differ because of the highly specialized approaches (and underlying look files) that different camera manufacturers have developed. For example, ARRI introduced a specific color-managed workflow to grade the Alexa 35 in-camera. This workflow creates new possibilities for SDR/HDR productions and even lets you grade in completely custom working colorspaces.
If you feel like we’re moving too fast already, don’t worry. We are about to go all the way back to the basics: With this article, we are kicking off a three-part blog series that provides a comprehensive overview of the concept and process of in-camera grading. In this first part, we will explain what in-camera grading even is and why it’s worth exploring. We will also look at a few potential setups with Livegrade to lay the foundation for the following article. Part two provides a step-by-step explanation of an in-camera grading workflow, using the ARRI Alexa 35 as an example. The third and last article of this series will then take you on a technical deep dive into custom color management and explain ARRI’s latest developments in the field. But first things first!
What is in-camera grading?
Most cinema cameras from key manufacturers like RED, Sony, or ARRI allow you to load a look file directly into the camera and apply it to its signal. That way, the camera outputs (including the viewfinder) can show an image that already reflects the production’s intended look. Now, in-camera grading describes the process of accessing and changing this look with an external device, for example, a computer running Livegrade, which is connected directly to the camera via ethernet. The adjusted look files get saved as separate metadata alongside the original camera footage, from where they can be accessed for dailies creation or further processing in post. The graphic below illustrates the described concept:
Benefits of in-camera grading
Now, with a general overview in mind, let’s take a closer look at a few characteristics that might come in handy in certain production scenarios:
- Compact setup: In-camera grading can be done with a relatively compact setup, as it doesn’t require a LUT box. This could make it an interesting option for projects in controlled studio environments with stable network connections, like commercial shoots.
- Instant preview: As with live grading in general, you can pre-visualize and interactively adjust the creative intent on set. Thus, you can give everyone a clearer idea of what the production is meant to look like. With in-camera grading, even the viewfinder shows the applied look, which could add further value for the camera department.
- No look-matching: As briefly mentioned, the applied look will be saved as metadata alongside the original camera footage. The look automatically travels together with each copy of the log-encoded OCF and can be quickly accessed for further processing during dailies creation or in post-production. Since the look is saved as separate metadata, it is, of course, possible to change it later on. This makes in-camera grading interesting for projects where looks have to be adapted within a short production time; again, this could be the case in commercial shoots.
While these aspects could be beneficial, it heavily depends on each individual production, whether (and to what extent) in-camera grading actually contributes to the efficiency of your workflow. So, naturally, you need to consider a lot more factors when designing your workflow. However, for the next section of this article, let’s assume you decided to opt for in-camera grading and are planning to design your setup with Livegrade.
In-camera grading setups with Livegrade
As mentioned before and illustrated in the comparison below, traditional live grading setups usually involve a LUT box (see upper image section). In this scenario, the grading is sent to the LUT box, which outputs the graded image for display on a monitor. In addition to this traditional approach, Livegrade also allows you to access the camera’s look directly via ethernet and use the camera’s output to view the live-graded image (see lower section). At first glance, removing the LUT box from your live grading setup seems like a simplification, and this is true if your only concern is hardware. However, the practicalities of live grading in-camera can, in fact, become much more complicated. Hence, we want to discuss some important aspects to consider when planning your in-camera grading setup.
Consideration 1: Getting an image source in Livegrade
Whether you’re grading in-camera or through a traditional setup, sharing still images is usually an integral part of any live grading workflow. To manage your shot library and share stills, you need an image source in Livegrade. Ideally, these stills are log-encoded, as this gives you maximum flexibility when creating looks. In traditional setups, you can easily pull such frame grabs via your LUT box. So what if you opted for a setup without any LUT box? Some cameras, like the ARRI Alexa 35, can send log-encoded frame grabs directly back to Livegrade. As of now, be aware that requesting a frame grab from the camera usually takes much longer than from LUT boxes. Multiple seconds are quite normal, even on a hard-wired connection.
Pictured below is a potential workaround: If you need a more reliable image source, you could consider introducing a capture device to your slot and feeding it with a log signal provided by your camera. This way, you would still benefit from the preview functionality and look persistence of in-camera grading while also getting an image stream from your camera.
Consideration 2: Setting up reliable connections
Another aspect we should look at is your connections. As with every other connection on a film set, the hard-wired way always offers more stable and, therefore, quicker responses. However, sometimes, a hard-wired connection is simply not possible – for example, when connecting the actual camera to your computer. While there are pretty reliable solutions for transmitting images wirelessly (e.g., using Teradek video transmitters), grading a device via the common Wifi bandwidths usually won’t work as well. So, what are your options if you want to grade remotely without sacrificing a stable grading device? As visualized below, you could introduce a LUT box as an additional device to your slot.
In the depicted hybrid setup, you would transmit the log image wirelessly to your DIT cart and feed it into a LUT box. As your LUT box could potentially be positioned directly on your cart, you can connect it to your computer via hard wire and thus benefit from a live graded image on your DIT cart’s monitor. Be aware, though: Due to the wireless connection to the camera, the camera’s outputs won’t be updated as quickly as your LUT box output. This might not matter as much since a lot of crew members don’t really prioritize the fluent representation of grading adjustments. Please also keep in mind that in this wireless-remote setup, ad-hoc look adjustments might take several moments until they are represented and stored in your camera.
Outlook
Lastly, let’s peek at a setup that will become relevant in the next article of this series. The hypothetical scenario depicted below assumes that you want to grade the Alexa 35 in-camera to manage dual-monitoring setups for SDR and HDR.
In the next article, we will use this example to walk you through each step of the process and explain the overall workflow. Please remember that this is a highly simplified scenario and not meant to depict the actual reality of a film set (where things are usually even more complicated than in theory).
Conclusion
For maximum flexibility in your workflows, Livegrade applications support both traditional live grading workflows with LUT boxes and in-camera grading. We hope this article gave you a better understanding of the latter and provided you with an overview of potential benefits and setups. In the second part of this series, we will take your learning further and explain the actual process, taking the Alexa 35 as an example. Stay tuned!
