In this video, learn how to create a lookup table inside of an application like Photoshop to get it to adjust the perceived colors, lighting, and scene image via tone mapping controls and color grading.
- [Instructor] Controlling specific values for certain aspects of a scene, as we have been doing in this chapter can oftentimes be all that we need to do in order to achieve the look that we want. At other times though, we might want to give our environment something very specific, which may in turn require digging into color grading by means of a lookup table or LUT. These, in Unreal, being image files that you use a specific format to alter how the camera perceives colors and/or values in our level. The question then is how do we create and apply such an image file? Well, let's first of all, take a look at applying a LUT. With out first option, color grading LUT, we can see that if we enable it, we get to pick a file to be used as the lookup table. Now, we have already saved a .png and LUT file for the use of this project. And so after enabling the checkbox, we can click the dropdown box and select it from the list or simply drag and drop it from the content browser. Now, things don't look too good at the moment. I'm not really selling this tool, am I? And that's because when we import a PNG as a LUT file, we need to make just one change and so let's double click on the file in our content browser, locate the level of detail tab and drop down the texture group list. From here, we want to tell Unreal that this file should be classed as a color lookup table. And then save and close the editor. Now, we should see our scene looking very different. Now, don't forget, because of the example we see here, we might just think well, it's just simply changing the colors in the scene and so it's nothing to get too excited about. But keep in mind that this is the same process used in films and game cinematics that can completely change the look and feel and even the perceived quality of a shot. Now, we can do the exact same for our visualizations to create or invoke a field or mood as well as add a measure of quality to the final project. So to actually create a LUT, such as this, and give ourselves complete freedom over the color grading of a scene, I've provided a default file in the exercise files folder that came from Epic Games. To create the kind of cinematic looks that we just spoke about, well, it doesn't actually require a ton of work. Actually, it is quite simple. We just take a screenshot of our level and place it in our 2D editing software of choice. In this case, Photoshop where we can now start to think about the type of mood and look we want and so craft our scene's color corrections. For demonstration purposes, I'll make some quick adjustments via adjustment layers but you really should take your time with this. Once we have the scene looking how we would like it to look inside Unreal, then we simply drag and drop these adjustment layers onto the default LUT file and save out a new PNG. And then we're good to go and change our mundane-looking scenes into something amazing. Back in Unreal, our color grading LUT intensity, well, this is a handy little control that lets us dial the effect that the LUT file is having on our scene either up or down, which we may again need to do on a per-volume basis even when using the same LUT file. For this course, I will leave this at a value of one. What we have hopefully seen in this exercise is that if we have a specific color look or field that we want to apply to our scene, then lookup tables give us quite a painless and yet very powerful way of altering the look of a level as a whole or on per-volume basis in a nondestructive way. We can even create multiple LUTs if we want and add them to multiple post-process volumes in order to create room or area-specific looks for our visualization pieces.