LUTs With Guts
What is a LUT (Look Up Table) and how can we use LUTs in still photography? A LUT is a color reference model that alters given RGB (red, green, blue) color values to create an alternative set of RGB color values. More widely used in video, LUTs can be useful in our digital photography as well. In post-production, the use of a LUT changes the color composition but does not change the working color space of your art or photograph. LUTs cannot rescue a poor exposure.
LUTs are a big deal. LUTs are frequently used in video to simulate movie film or create a mood. We can also use LUTs in our photography workflow. LUTs are not presets as they alter only color values but LUTs can be applied to an independent Adjustment layer while using, for example, ON1 or Photoshop post-production software. In Photoshop, a LUT Adjustment layer may be created by clicking the 3 x 3 grid icon to center right of the adjustment icons. In the panel that pops out, we choose from among an assortment of 3D LUTs (top row “3DLUT File” drop down arrow). It appears to me that 3D LUTs offer substantive advantages over 2D LUTs.
Most commonly in photography we may alter the color tones of an image by increasing contrast, creating a black and white or split-tone image, or altering white balance (degrees Kelvin or color temperature) values. These changes can also alter the mood of an image. It is safe to say that even subtle changes in color or tonal values may alter the mood of an image. Who hasn’t added a touch of warming filter in post to make an image “happier.” So, the alteration of hues in still photography to convey mood is not atypical. Warmer or cooler color temperatures affect us emotionally. Now for an example of the application of a 3D LUT….
Second image altered using Photoshop’s 2Strip.look LUT. Say, I like that!
A 1D LUT may be used to alter individual red, green, or blue color channel brightness, contrast, or black and white levels. However, a 3D LUT can also alter the relationship between colors to include saturation and hue. Credit: What Is 3D LUT & How to Use 3D LUT Creator for Color Correction? (minitool.com) and: http://www.fallenempiredigital.com/blog/2012/12/04/luts-part-1-what-is-a-lut/
In Photoshop, you can use as many LUTs as you wish to create using Adjustment layers but what’s the point? If a properly designed LUT creates image personality, do multiple LUTs create a split personality? Perhaps so.… Of course, the opacity of Adjustment layers is easily altered or masked using Photoshop, so the user has great control over the LUT. But, once again, doesn’t this defeat the purpose? I want a LUT to be the final touch created by a genius for just the right touch of color and luminance to turn my meritocracy into destiny. Can that be done? No. The variables within infinite possible images are too great. But Photoshop does approach this, for example, one LUT is named FallColors.look another HorrorBlue.3DL. Similar names help to guide our selection(s).
I acquired a number of LUTs online having a .cube file extension. They downloaded as one compressed .zip file. I copied the file to a LUTs Folder I had created (right click, New > Folder). So, this .zip file is the only file in the LUTs Folder. I right clicked on the .zip file which provided an “extract” option that allowed the extracted LUTs files to be placed in the same Folder. I then copied the files to: C/program files/Adobe/Adobe Photoshop 2023/Presets/3DLUTs using Windows Explorer (I had to assert Administrative Privileges for the files to be copied). It is best to open two instances of Windows Explorer and place them side by side when transferring files. It makes the process quite easy and less prone to error. You can select all the LUTs at once and simply drag and drop them into the 3DLUTs Folder. I restarted Photoshop and the new LUTs were available. I backup all presets and LUTs to several different hard disks and an external DVD.
To save your own LUT for an unmasked image in the Background layer: File > Export > Color Lookup Tables… and select your options. For detailed information see: https://digital-photography-school.com/create-your-own-style-using-luts-photoshop/
DxO FilmPack 6, offers a post-production software package that allows us to simulate a host of film colors and film characteristics. Something like LUTs on afterburner.
Applying a LUT is, in my opinion, a final act in post as any further adjustment will alter the LUT.
“In the film industry, 3D lookup tables (3D LUTs) are used to map one color space to another. They are commonly used to calculate preview colors for a monitor or digital projector of how an image will be reproduced on another display device, typically the final digitally projected image or release print of a movie. A 3D LUT is a 3D lattice of output RGB color values that can be indexed by sets of input RGB color values. Each axis of the lattice represents one of the three input color components, and the input color thus defines a point inside the lattice. Since the point may not be on a lattice point, the lattice values must be interpolated; most products use trilinear interpolation.” Credit: Wikipedia: https://creativecommons.org/licenses/by-sa/3.0/