There is a vast amount of literature on the color theory and color grading and setting up LUTs in a variety of applications but this is a tutorial showing the basic creation of a LUT and the application of a LUT as well as creating tools for more abstract purposes than perhaps matching up film footage / photos etc. You can use them for all kinds of visual effects as well as a more standard use of the tool. Until recently you could use a LUT in Photoshop via the image menu and adjustments as well as via the layer menu and adjustments. You can see from this, the key thing is adjustments and layers and that is what is needed to create one. If you go to the file menu and export command (if you are using a fairly recent version of PS and have the correct requirements for the use of the tool) you will see the option to export a number of file formats such as 3DL and CUBE and CSP and ICC profile (again, not going to go into those formats and they all have their uses for different types of operation) as well as a quality - you want to keep it as high as possible but you can also use a low quality to create some oddball abstract artwork. All really depends on the underlying image as well, some work well with the results and some, well they will be just a mess (such as in trials with gradients I found there were quite a few variant results with subtle changes of gradient and color lookup). Below is the original image which will be combined by a number of example LUTs
You can use one adjustment layer on top of a test image or multiple adjustment layers but you must have one to be able to create the files to be used in future projects. The type of image to use, well, I guess it helps if the picture is not all a solid color and is roughly similar to the items you want to work with. PS comes with a large selection of useful presets for the adjustment 'color lookup' but not all are the same on the PC and MAC, so you will see some in the list on one platform and not on the other and vica versa (for whatever technical reason). You can create some interesting color effects by using such as the bleach bypass or blue tone etc but again, really depends on the underlying picture to that actual results generated. The adjustment layers can be any of the adjustment layers (sadly not all the adjustments in PS are available as adjustment layers such as match color which would have been useful here). The adjustment layers include black and white (useful), invert (fairly limited but of use), exposure, hue and saturation, photo filter, color lookup (you can use one to create a new one, why not). So once you have all these, you can now just add them to an existing image. Below you can see one generated based on the black and white layer and then blended using the darken blending mode
The one below was created using a combination of vibrance and hue and saturation with the colorize set to red and a high setting for the lightness.
You can add two or three of the same adjustment layers (why not) and you can also mix in opacity via the layers panel and also different blending modes (such as hard mix or hard light or difference) as well as other modifications to the layer (it is a layer in exactly the same way as a normal layer and can have all kinds of extra twists such as gradient overlays and satin to change the adjustment). And all those changes will be reflected in the actual color lookup generated (not perhaps the best way to generate gradient overlays for use in other apps without the need for layer styles but it does seem to work in a garish way). Dark style added via black and white and blending mode and vibrance combined below
Or using the curves layer as well as a lookup combined to blast any image (below)
Below, a gradient overlay was added to a layer and then that was exported as a CSP etc file
Weirdly, the export also can use other layers and not just adjustments so if you create a new layer and then fill that with a gradient or pattern or brush strokes, that also can be used as a color lookup - so much for the warning message about adjustment layers. The image below uses a pattern layer made up of black and white scratches and lines (again, slightly blurred to reduce the file size) but the end result is more like the chrome filter found in the filter gallery.
Or using a combinations of gradients to a layer (and that is the key thing) though the actual result can definitely depend on the underlying image and how everything maps out.
You can use all kinds of manipulation of the adjustment layers (especially combining with gradients in layer styles) or by using the gradient maps but you can also use that in combination with other layers to create even more extremes of color. Example below using a single gradient map with one of the default presets
Below, using a map with a lot more stops (26 stops added instead of just two or three as above)
You can use the color lookups to create some truly garish color shifts but you can also use it create more subtle changes such as minute changes to the red or perhaps a very light gradient change. This depends on the adjustments you use such as hue and saturation or vibrance and very slight changes to those, especially combined with a lowering of the opacity
The various files generated such as CSP can be pretty large, 10MB for a fairly average sized file and using the default setting, likewise the cube is about the same with the 3DL a little smaller and ICC running in at about 2MB in my runs. When you come to run the color lookup, select the first item in the panel and load the file (the others are abstract and device link and seem to generate a warning message with the generated files or perhaps that is just me). When you add the layer, you will get the subtle color change or black and white or garish effect and the results may often bare little resemblance to the original image color effects. You can, of course, manipulate that as well such as changing the blending mode or adding other layers above that or using the same layer again or perhaps adding a gradient to modify that layer. If you push up the quality to say 200 then the result of the generated CSP etc files can go up to 225MB or so, so the presets are not really that small. Actually adding a high quality CSP etc file can take a very long to process. You can also go for the opposite and select the lowest quality (7, it seems) and that can create some unusual color changes. Can be used to create some weird out of world painted looks especially when combined with other effects such as oil paint filter
You can also add more layers with the same 'poor' quality LUT using the duplicate layer in the layer menu and also combine with oil paint etc (as below)
Using a black and white layer with the 'poor' (lowest setting) and the generated LUT layer was duplicated a number of times and is great for creating interesting dark and gloomy imagery. You can modify the layer by using gradients or perhaps effects to add different color highlights or perhaps add shapes to the artwork such as grid to modify the layer
You can also use the LUT with the video timeline in Photoshop, simply add the adjustment layer above a smart object timeline and the entire movie will be turned into a very dark and gloomy or red etc video once rendered as MP4 etc. It should be noted that sometimes the result of adding the effect can generate unusual artificats with certain images and that a high quality file may result in a worse conversion than a low quality one where the color range does not ruin the end result video. Anyway, the key thing is to carefully check the video before loading it up to sites such as Youtube (as I have found out to my cost many a time). What works well with an image may not end up as good with a video but at the same time, some really unusual video effects can be created using the files
You can also create interesting color lookups in Affinity Photo via the export menu. Still requires the use of adjustment layers but you can still use the app to create some very subtle as well as extreme color effects. The nice thing about that tool is that you can save one format and also you get a nice preview of a cat (unless you load your own picture). There are also many other apps that can be used to create the files.
Here is a video on the subject created by us a while back giving some details about the feature.