Introduction to 3D LUT Creator
In some recent Youtube Videos and Lenscraft articles I have been talking a lot about the technique of Color Grading and how this can be used in Landscape Photography. In last month’s newsletter I published an article explaining how to apply Color Grading in Photoshop using Color Lookup Tables or LUTs. In this article I want explain how you can create your own LUTs for use with any of the image editor that supports this technology.
Although, as I demonstrated in one of my Youtube videos, you can create your own LUT’s in Photoshop, the process is a little limiting. If you want complete freedom over the LUT creation process you need the right software package. In my research, I found the best combination of price, features and ease of use was “3D LUT Creator” and I’m going to explain the process here.
If you would like to follow along you can download a free version of 3D LUT Creator from https://3dlutcreator.com/. The only limitation of the free version is that you won’t be able to save the finished image or the LUT you create. It does though allow you to understand the power of the program and if it’s for you.
Launching 3D LUT Creator
Start by launching the 3D LUT Creator software and open the image you want to work on.
Here you can see the 3D LUT Creator interface with the starting image open. On the left side of the interface, surrounded by the red box are the editing tools. The editing tool shown in the illustration is the “A/B Grid” which is very intuitive but also very powerful. You can see the “A/B” title indicated by the small red arrow and there are other tools on this menu.
The grid itself looks like a spider’s web and provides control over the colours in the image. Below this you have the more traditional, slider-based tools that most photographers are familiar with. Separately, there is a small Analyser floating window that displays helpful information about the image being edited. You can see an example of this below.
Examining the image being edited, it would benefit from being a little warmer, more saturated and possibly a little brighter. I would also like the warm tones in the top right to appear more golden.
Applying Corrections with 3D LUT Creator
These changes are applied with the following slider adjustments:
Temp = 10 – This slider increases the colour temperature of the overall image, moving it from blue towards orange.
Contrast = 20 – Initially, I was expecting an increase in the contrast slider would push the histogram out at either end, whilst reducing the contrast would contract the histogram into the centre. This doesn’t seem to happen and instead, reducing the slider moved the bulk of the histogram into the midtones from the highlights. Increasing the contrast moved the midtones and shadows towards the highlights. Based on the visual result I increased the contrast.
Pivot = 30 – This is a slider that I don’t currently understand (I need to read the manual). I can though see the default is 50 and reducing this appears to compress the histogram into the highlights area for this image without causing blown highlights. Nice.
Dynamic Range = 10 – This adjustment is being used to intentionally limited highlight clipping in the very brightest areas where the sun is breaking through the mist. If you move the slider in the opposite direction it limits how bright the white areas of the image appear. This would probably be a very useful slider if you are editing a snowy scene as it would allow you to show more detail in the brighter areas of the snow.
Saturation = 120 – The default value of the slider is 100 and increasing it adds further saturation to the image.
Using the “Compare” button in 3D LUT Creator we can examine the changes by comparing the current version of the image with the starting image. You can see a screenshot of this below. The before image is on the left and the after image is on the right.
Comparing the two versions of the image, there is a colour shift in the blues which is causing them to appear slightly purple. We can target a correction to this using the spiders web grid.
Adjusting Colours witht he A/B Grid
If you look at the A/B Grid you can see that there is “colour wheel” behind it. The points on the grid represent the colours on the wheel. By clicking and dragging a point, you can remap a colour to a new colour. This is quite sensitive and can create some very interesting or bizarre effects as shown below.
The adjustment above targeted the blues in the image, moving them towards blue/green or teal. If you make a mistake and want to reset the grid, there is a reset icon just above the top left. Clicking this resets the grid to the original position. If you want to undo a single change to the grid, use the “Edit | Undo” feature in the menu to work back through the history of the changes.
There is though a much easier and more intuitive way to make your adjustments to the image that dragging points on the grid. By clicking a point in the image that you want to adjust, and then dragging this left, right, up and down, you change the hue of that colour. As you click and drag a point in the image, you will also see the corresponding colour points on the grid move.
Clicking the blue area in the centre of the frame and dragging slightly left and down the purple hue of the blue is corrected by shifting towards green. It was then possible to make the sky appear more golden by clicking and dragging left and up. To show you how small the adjustments to the grid were, here is a closeup of the grid.
Saving the Adjustment Results
Having corrected the colours in the image it was possible to increase the Temp slider further, to a value of 15. Having applied the adjustments to the Grid, click the “Smooth” button. This makes small adjustments to the grid and appears to smooth out the image tones (I really should read the manual). Here is the finished side by side image.
The resulting image can now be saved in several formats including TIFF. When saving, it’s pleasing to see you have control over the quality of the saved image as well as the colour space. These can be set using the program preferences.
If you want to create a LUT file using the adjustments applied to the image you can select “File | Export” to export it ready for use in supporting software applications. Several LUT formats are supported including “cube”, so you should find a lot of compatibility. There is even an option to export and install the LUT directly to Photoshop.
What’s most surprising is that even a simple LUT such as this one, can have a dramatic effect when applied to other images.
If you’re interested in seeing the LUT creation process demonstrated, I created a short Youtube video you can watch https://www.youtube.com/watch?v=1lYgWaSun0U&t=8s.
I would also recommend watching the tutorials on the 3D LUT Creator website.
If you want to create your own LUTs, 3D LUT Creator is a great place to start.