![lightroom presets in rawtherapee lightroom presets in rawtherapee](https://retouchinglabs.com/wp-content/uploads/2024/01/lightroom-presets-pack-free-retouchinglabs.jpg)
"CLUT" means "Color Look-Up Table", while what "Hald" means is anyone's guess. The Film Simulation tool uses specially prepared images in what is called a HaldCLUT pattern. The level 12 Hald_CLUT_Identity.tif image.
![lightroom presets in rawtherapee lightroom presets in rawtherapee](https://weandthecolor.com/wp-content/uploads/2021/02/Best-Lightroom-Presets.jpg)
As you can see, there is no reason to worry when using HaldCLUTs as long as you use a dedicated folder as suggested, keeping only HaldCLUT images in it. If, however, you were to accidentally tell RawTherapee that the HaldCLUT folder is C:\Program Files (x86), then the startup time could even take several minutes, as that folder contains hundreds of thousands of files. To give you an idea of how the startup time is affected, the difference between having 0 images in the HaldCLUT folder and having 500 images in it (that's more than in our collection) results in a 100ms startup time difference - that's nothing. Should that happen, just click the button in the popup to stop the scan, then go to "Preferences > Image Processing > Directories" to see which folder is being used, and either point RawTherapee to a folder which contains only HaldCLUT images and nothing else, or to an empty folder if you don't want to use the Film Simulation tool. As a safety measure, you will be warned if scanning the folder on startup takes more than 10 seconds. RawTherapee will scan the designated HaldCLUT folder every time you start the program, that's why it is important that you create a folder which you will use only for storing these HaldCLUT images and nothing else, so that RawTherapee does not waste time scanning unrelated files.
![lightroom presets in rawtherapee lightroom presets in rawtherapee](https://pixls-discuss.s3.amazonaws.com/original/2X/1/173d171def52c76986c7f17da175f560a17d2868.jpg)
The Film Simulation tool can change the look of a photo to match a film stock with a single click.