If you are a fan of using Look Up Tables (LUT) in your render’s then you have probably seen many packs online for purchase recently. LUT’s are a a way of displaying footage or images shot in a different color space to the intended space for your output. For example if you have received LogC footage from a client and wish to display it on a standard sRGB monitor you can apply a LUT to do this for you and then color grade in the correct space.
Image as LogC
Image as sRGB (Rec709) Photography Courtesy of Jonathan Cosens
Many of the packs online available for purchase have prebuilt LUTs designed to give your render a final grade (kind of like an instagram filter). However with 3DLUT Creator you can make your own LUT specific to your image, match colors to a reference image, fine tune color adjustments for grading which saves you time in 3D and then display this in your VFB so you have your graded image in display while you render. Below is an example of a photo from unsplash we will try to match using this method.
Photography courtesy of Sonnie Hiles
I have gone ahead and built a scene similar to this one in 3D and left the tone mapping as default, so no adjustments to white balance and some materials were not the right colors but close enough to match in the LUT creator. You can see side by side for reference.
Image Comparison of Reference vs Render
We will now use 3DLUT creator’s Auto match reference tools to get a good base point for correcting.
Auto match colors to reference
To get a better understanding on how the sliders work you should watch this video. Instantly its closer however some colors have shifted into the green such as the wall. You will also notice the colors on the top left hand grid have shifted so we can select the areas on the wall or ceiling and move them to be warmer. I have also done this manually on the floor to get that nice blue color. Depending on which window you are in (we are currently in the AB tab), you can just select an area of your image and drag it. When you are in AB mode we can affect color directly, you can also switch to other modes such as the Curves and adjust luminance separately, hue, saturation or separate channels. You can see a few more adjustments I have made in the Channels, Volume, AB, CL, and Curves area for fine tuning.
Once you are happy with the results you can then save this LUT out and apply it in your renderer of choice. The great thing is you can do this for any 3D software that allows you to use LUTs, you dont need to do any internal tone mapping and you can even work on low resolution outputs while your still rendering in the background. You can either bake this into your final render or if you prefer you can use it as a preview in the frame buffer, switch it off for final and import the LUT into post production for grading there. I prefer the latter option as sometimes there may be a few things I want to still change manually in post production, here is the final result.
Final result with Tone Mapping in 3DLUT Creator & minor adjustments in Photoshop.