"I just bought the ImpulZ LUTs and I have been playing around with. They look great out of the box but I want to make sure I'm getting the most out of the library and use all available options correctly."
The ImpulZ™ LUT Library contains so many LUTs with so many input / output options for each emulated film stock, it is no wonder that it can be a little overwhelming at first.
If you've never worked with analog film in a traditional motion picture pipeline the following overview aims to better familiarize you with these concepts to greatly improve the quality of color you can create with the help of ImpulZ.
Overview of the Library
1. Folder Structure
After you have downloaded and installed ImpulZ, the library folder called "ImpulZ Ultimate" is stored on your local hard drive. By default this folder contains many sub-folders for each supported input device.
The folder names directly reflect the name of the camera and / or color profile and should be self explanatory. There are however three folders that deserve special attention:
- LOG Generic - The LUTs contained in this folder can be used with any camera that records LOG gamma. They can be used if a specific camera is not supported or as an alternative to existing specific calibrations. They are working great for LOG-C, Sony S-LOG 2 and 3, Panasonic V-LOG and more. Some users prefer them over the device-specific calibrations!
- Rec709 Generic - These LUTs can be used with any input that falls into the Rec709 or sRGB color space. This covers almost all cameras and content that can be displayed on monitors and TVs. These LUTs have exceptional transform stability and you should definitely not dismiss them just because they are labled "generic". In some cases they create better results than specific calibrations!
- Cineon Conversions - The LUTs in this folder are completely different from all other folders. Why? Because all other folders contain emulations of Color Negative Film Stocks. The Cineon Conversions folder contains complimentary Color Positive Film Stocks (and some utility LUTs). These are required for the true 3-Step Hollywood process. We're going to look at this in more detail in a bit.
2. File Names
Inside each of the Color Negative Folders (all folders but Cineon Conversions) you will find a long list of files with very long and intimidating file names. Fear not! Once decrypted the naming convention we chose for the LUTs will help both your applications and you to quickly navigate and identify the various film stocks. Let's break down the file names visually:
The file names simply reflect this i/o flow of image data:
INPUT describes the type of footage the LUT expects as input.
FILMSTOCK is the name and version of the color negative film that the LUT emulates. ImpulZ includes some LUTs which emulate different versions of the same color negative stocks. These variations are reflected in the filename as well. Don't let any vendor specific numbers or abbreviations confuse you. Anything between the underscores is just the name of the film stock. We will be looking at the available variations in a little bit.
OUTPUT is an abbreviation of the output profile of a particular film stock.
The output options are probably the most confusing but also the most important part to understand.
Let's go through each of these abbreviations (FC, FPE, CIN and VS) next to fully understand how ImpulZ LUTs can be used as modular building blocks and more.
We're almost there. The following is the last but most important piece of the puzzle that you'll need in order to start building truly phenomenal grades with these LUTs.
As we've seen above every Color Negative LUT in the library expects a certain input. It then accurately converts that input to the color space of a particular color negative film stock.
That alone is pretty cool but it gets better. You're not locked in to a single version of that film stock. Part of the beauty of real film is that it's super flexible - one and the same film stock can look totally different depending on how it is exposed, developed, processed or scanned.
To help you leverage this unique quality of film with the ImpulZ LUTs, we're giving you not one but four options to render each film stock.
The simulator below should help you quickly identify each output. Click the blue button to get started. You can always toggle the before/after by clicking and holding anywhere on the image.
4 Outputs per LUT. Ultimate Color Control.
Every LUT in ImpulZ comes in 4 versions - including Cineon™ LOG for pro color workflows. Creating big looks has never been more simple.
FC - Film Contrast
Non-linear distribution of image saturation with a film-like gamma curve.
These LUTs render a representation of the color negative film stock that can be directly viewed on any monitor and tv. When you apply them to your footage they will "look correct" because they generate a Rec709/sRGB image. You can think of these LUTs as the "default" LUTs in ImpulZ. They simply emulate a color negative film stock for monitor viewing.
They are also great options for in-camera or on-set monitoring. You will essentially be able to preview your scenes as though you were shooting plain analog film.
FPE - Film Print Emulation
Industry Standard Vision 2383 film print. Medium contrast/saturation film stock with a warm white point.
FPE LUTs emulate two films at the same time. The color negative film ( as indicated by the filename) printed to Kodak Vision 2383 positive film. Back in the film days you shot on a capture stock - the color negative, then did your edit and finally printed your edit to a print stock for distribution. The FPE LUTs emulate this process in a single LUT file by applying the look of the capture stock (Kodak Vis3 50D 5203 for example) and then the look of the print stock.
Just like the FC LUTs, FPE LUTs are a great companion for on-set monitoring, in-camera previews and simple, hassle-free grades. The film print used by the FPE LUTs does have a relatively warm white point so be sure to compensate by turning down the whitebalance a notch (in camera or in post).
VS - VisionSpace™
Custom semi-flat gamma response curve. Ideal for starting a grade.
The VS LUTs are the simplest to explain because they are the same as the FC LUTs but with a flatter gamma response curve. They are not as flat as the following CIN LUTs but offer much more wiggle room for adjustment than the FC LUTs and are thus ideal if you want to dial in your own contrast and saturation without having to go through the full Cineon workflow described below. Whether you want to use them in production or not depends entirely on your workflow. A lot of ImpulZ heavy-users are using the VS LUTs as a base to create their own custom LUTs for their personal library. This is of course possible and encouraged with any of the other LUT types but VS has been particularly popular in this regard.
CIN - Cineon ©
Industry Standard Cineon LOG Compound gamma (95-685).
This output emulates the gamma response of the raw film scans from a film scanner. These LUTs are the real deal. They don't look like much when you apply them by themselves but that is not their purpose. Cineon LUTs produce a very flat LOG image and need to be graded back to a "viewing gamma" or virtually printed to an ouput LUT. That probably sounds more complicated than it really is. In fact, the process is quite simple - because ImpulZ does not simply have this feature built in as an afterthought;
It has been a core design choice of the entire library to allow colorists to extend Cineon LUTs with special Cineon Conversion LUTs that perfectly interconnect with each other.
Remember the Cineon Conversion folder mentioned in the Library Overview? Try adding any "Cineon to XYZ" LUTs from that folder on top of a color negative LUT with the CIN suffix.
"Learn the rules like a pro, so you can break them like an artist."