Ben Turley wrote a utility called LUTCalc which offers incredible flexibility in converting between camera colourspaces, tone curves and creating correction LUTs. Arri has a LUT generator online which takes Alexa Footage and allows you to generate a LUT to transform it to Rec709 or some post production orientated colourspace. Sony offer a bunch of LUTs to again convert from camera to various display colourspaces. They take a wide colourspace of a camera, transform it to other spaces and allow you to quickly see an image that looks 'correct' on your display. LUT examples - 4 examples, from No LUT to three differnet LUTS applied. The exposure response appears different in each of these LUTs as well.Ĥ examples, from No LUT to three differnet LUTS applied. The exposure response appears different in each of these LUTs as well.īASE SRGB IMAGE - This is the control image. It has a hue circle and two others at +2 stops and -2 stops. This helps us compare LUTs like for like.ģD LUTS are often sold as ‘looks’ or ‘film emulations’, they ‘bake' in a certain look that would be very difficult to create manually. Modelling the look of a particular stock of film is a great example. The LUT can not only change colours but also the tonality of the image to something that looks filmic. Indeed the very birthplace of LUTs is to be found in the DI. When you’re working digitally the film out company could provide LUTs specific to the film stock you will be outputting so when grading you can view your image under an emulation of how it would look projected from film. Of course the usefulness of this is apparent, you can now use similar LUTs to make your digital video look filmic. And indeed there are many commercial products for doing this. Are they all wrong? Not really, they have a use. Purists will argue that anything that can be done via an emulation LUT can be graded, which is true. Lutists will argue why waste all that time. The subject of film emulation will be brought up again in another post.Ī 3D LUT is a one way street though, because once you’ve transformed your image you cannot transform it back. If you take every RGB colour and transform that to a shade of purple. Then once you’ve got your purple image how can you go back? All your pixels are now purple and you cannot separate the original colours. So 3D LUTS are usually destructive to the image. KODAK FILM EMULATION - After passing the hue circle through a Kodak film emulation lut, see how the colours have changed. This is a complex colour transform based on analysis of actual filmīut this post is pointless without examples. If you click on the image and view the full version that's better, the full versions are PNG files, so no JPG compression. You can flip back and forth to compare them as well. So here is my sample image, first of all in pure RGB goodness. Full saturation, full range, bright and video at its finest.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |