Sherif Mokbel | BLOG Menu

Permalink:

Grading GH4 with ImpulZ LUTs

I got the ImpulZ Pro LUT set the day it was launched mainly because this is the first LUT set to consider GH4 in its presets.  ImpulZ is a film emulation LUT product, created by VisionColor and distributed by Denver Riddle, founder of Color Grading Central. He has been offering us a superb collection of color grading tools for our modern digital cinematography workflows, so I was sure I’m getting a product of a high quality from him and his affiliates.

Camera settings:

CineD picture Profile

Master pedestal +10

Highlight -5

Shadow +5

NTSC 60FPS

Lenses:

Panasonic 12-35mm F/2.8

Panasonic Leica 25mm F/1.4

Panasonic Nocticron 42.5mm F/1.2

Editing:

Final Cut X

25FPS timeline for 42% slow motion effect

LUT Utility to apply the LUTs

Disclaimer: 1- I’m not a color-grading expert, I’m a Director/DP and I grade my own films using basic methods and techniques such as applying LUTs or a set of presets then further tweak them to achieve my desired final looks. I do have the basic and essential understanding of the digital color grading process though. 2- I have not been commissioned by Color Grading Central to write this review. I’m a loyal customer to their products and I’m simply sharing my thoughts and experience.

 

First impressions:

ImpulZ is a similar product to Film Convert, they both emulate famous 35mm film stocks using LUTs, both work in the same method but using different workflows and user interface. Film Convert hav their LUTs integrated in the plugin, while ImpulZ have them separate and are applied using LUT Utility in FCPX, my NLE of choice.

I was surprised by the huge amount of LUTs that existed in the Pro version. I assume the Ultimate version will probably double if not triple those of the PRO’s.

Each film emulation (such as Fuji Superia 200) has almost 10 versions or more (I lost count). Not necessarily a good thing though, as it gets a bit overwhelming. We’ll get to that later.

I noticed that in the downloaded documentation Denver stated: “These LUTs are no one-click-make-awesome solutions to color grading but will take the digital edge off your footage and provide an ‘analog framework’ that processes colors more deeply than what is achievable with user interface controls.”

So with this in mind I carried on and threw myself into applying those bad boys onto my freshly baked GH4 clips.

 

Why this overwhelming amount of LUTs?!

To emulate real life Grading process, you need to consider and simulate the same process’ workflow. Which starts with 2 input types (Camera Type+Input Patch) and ends with 1 Output (gammas and color response profile). Your creative color grading should be sandwiched in between those two. So with 3 variables for each Film Stock… you do the match and the result is the amount of LUTs you get.

Simply put, ImulZ provides you with all the color combinations possible of all the above. Each combination is a LUT. Which in theory is the same as Film Convert, yet the latter offers you drop menus from within the plugin to mix the combination of your choice, which I personally find more practical and user friendly.

Impulz-Lot o LUT

Click to enlarge… This is only a small portion of what you get… the list sculls down to almost 4X more than this!

 

How to use ImpulZ?

Before you start, DENOISE!

Denver advised us to chromatically denoise our footage before we start. There’s a GOOD REASON for that. The LUTs for some reason accentuates the compression’s macroblocking and even increases the colored noise. My plugin of choice is Neat Video.

Here’s the applied LUT with and without Noise reduction:

Impulz-NR

Denver provided a PDF that attempts to explain how to use them, but the language and terms he used felt like he was addressing Hollywood Grading Professionals, not the common public. The example mentioned was not clear enough to me.

Undeterred by the ambiguities in the PDF, I started applying them one by one and noticed that overall they’re very similar in the way they affect the footage. So I assumed I was doing something wrong. Then after further testing and research, I discovered 3 ways to use ImpulZ.

THE EASY WAY:

Just keep on applying each LUT to your footage and see which one fits your needs and taste. Remember that Denver was saying: ”These LUTs are no one-click-make-awesome solutions…” So result will act as a base, you will still need to tweak the look further.

You’ll soon realize that there’s a behavior pattern with each emulsion, which is related to the prefix and suffix of the presets, each refers to a process or gamma (FPE-VS-etc…). Some are more vivid, some are subtle and some are flat or washed out.

 

THE RIGHT WAY:

If emulating film stock is your main purpose (which is why ImpulZ was created), then first you need to understand more about all the color processes and their effect on the output. Then follow the proper inputs and outputs to get the accurate emulation you need, that does not mean you will like what you see or not, it means you will simply get an accurate scientific result that emulates the film stock you desire. It gets really confusing honestly and I personally lost interest in learning it. I’m sure DPs with great film experience will love this part.

 

THE CREATIVE WAY: “Digital Cross Process”

This method essentially lets you use LUTs not in their intended scenario. Basically you will be digitally cross processing your footage. This requires no previous academic or scientific understanding of film processes. It only requires patience and open mind for experimentation. And most of all, it’s FUN! As you’re literally playing around and creating a mess that will eventually look good.

I broke it down to 2 steps, step 2 has 3 options… I hope I’m not confusing you!

Step 1: Base Look

I choose a LUTs as a good base to start from. Ignore all the names, camera inputs and outputs and just have fun. Ideally find a LUT that offers a rather flat look, similar to the VS to Rec709 LUTs (find in 1:32 in my film). What we’re doing here is to have a  different starting point to our grading process. Each starting point will have a different result after applying all the grading effects in step 2.

Step 2A: Grade

With a base look applied, you can start grading using any tool you like, curves, levels, contrast, etc… (Refer to 1:34 in my film when I applied a basic S curve)

Step 2B: mLooks / MBL

With the rather more flat LUTs you basically paved the way to a whole new starting point for a third party plugins such as mLooks or Magic Bullet Looks to apply the creative “Look” to your clip.

Step 2C: LUT Stacking

Another way is to stack multiple LUTs on top of each other… Rotate between them, change their order to discover new possibilities. It sounds primitive, but believe me, things get very interesting.

BONUS INFO: Cross Process: This creative method is based on how creative color grading was born. Back in the days when color grading was more of a technical process to ensure accurate color reproduction across all output platforms, some photographers made the mistake (it might have be intentional) to processes a film in a chemical solution intended for a different type of film. The result was a very interesting and creative new look. Which essentially is what I tested here in 2:38 in my film when I applied Canon VT process to my GH4 CineD Clips.              

Before you finish: GRAIN

In the initial denoising process, the image will look too perfect and risk becoming plastic. So it’s highly advisable to add some film grain to your footage to bring it back to a realistic look. Unless you like the polished plastic look, it’s a matter of taste.

 

PROs:

1- More dynamic range: The LUTs virtually increases the dynamic range of your footage. Making the footage look flat… yet in a whole new and different way than how it was initially shot. Which is very useful for a base as mentioned before, so do consider this method when using it.

2- A LOT o’ LUT: There are so many combinations of the LUTs that you get lost in choice. Not always a great thing, but I like when the glass is half full.

 

CONs

1- Red tint: I noticed an overall red tint that characterised these LUTs. It could be dictated by the actual film it’s emulating, but at least half of the film processes have a very strong tint. Is it supposed that strong? Denver, any ideas?

 

2-Subtle differences: As much as there are so many LUTs to choose from, but the overall differences between the film processes are very subtle. They need to be dramatised with further color controls to establish the difference.

3-Banding: I noticed some banding that occurs in the areas where the colors rolls off from dark to bright.

Impulz-Band-Before After 

 

Who should get ImpulZ?

Always remember, the main purpose of this LUT set is to emulate the look of film. It’s not a LUT for special “Looks” such as Bleach bypass and Teal & Orange. ImpulZ achieves the film look in the most professional and scientific way. The outcome could be subtle sometimes… so it’s your additional tweaks that will give it a “kick”!

So if you’re looking for a more creative color grading LUT set, then you should either apply the Digital Cross Process I mentioned above to exponentially multiply ImpulZ’s potential. Or simply buy LUTs that are more dedicated to creating “Looks” rather than “Film Emulations” such as Speed Looks.

I personally find “Film Emulation” as a creative look on its own… subtle, tasteful and classic. 

  • You need to be logged in to leave a comment.