KODAK AHU technology: opinions, issues, reviews...

[Elena Bertelli Bianchi]

Hello community,

It's been 3/4 months since the AHU technology made its debut, what do you think about it? As cinematographers (or not), do you see any changes or differences? 

As a Loader I'm working with AHU since september and I noticed it feels a bit "softer", it tends to slide a bit more on itself than its predecessor when you load or unload it. Kodak claims that "The AHU stocks fall within the 5-micron range of low-to-high tolerances for remjet Vision3 thickness, with a differential of just 2 microns, a figure Kodak regards as immaterial." (American Cinematographer, august 2025) so I don't know if these 2 microns are responsible or if it was the rem jet layer that made the previous stock feel a bit more "stiff"...

Regarding visual performance I don't have much to say, hopefully somebody here will share their experiences. The only noteworthy thing I observed during camera tests relates to shots that include strong in-camera light sources (for example, a night scene with streetlights, or a interior with a very bright window in frame, or a big flare). The halo produced by very bright objects (relative to the overall brightness of the scene) seems to impress onto the next/previous frame, depending on the light source's position into the image. Kodak film already had this issue but with AHU it looks definitely enhanced (unfortunately I don't have any reference img to share). 

Last but not least, has anyone noticed a slight general decline in quality control? I often find the beginning of the roll scratched or with broken perforations , the sticker that keeps the roll closed fully glued down or badly attached, and sometimes the tape that seals the can is damaged (in some cases to the point where I had to send the rolls back to the supplier). Of course this part of the roll is only for threading the camera and it's not meant to be shot, but still... I do not remember the remjet stock being like this... 

That's the last fresh roll I loaded today, I'm finding this kind of things a lot... scratches are VERY common (first meters of the roll only), the perf damage is less common but has happened to me 4/5 times in the last couple of months (and it had never happened before)

Are you noticing the same issues or I'm just being unlucky?

 

[Tyler Purcell]

I haven't tested 35mm version yet, but with 16mm we saw no difference outside of it not having the constant remjet removal problems we found on the older film. Unfortunately, we can't get 35mm short ends of the new stock yet, but the moment we can, I will be buying some and testing on 35mm with a chrome pressure plate. The 16mm cameras seem to not be as effected with the halation issues, as the 35mm cameras with their chrome plates. 

[Elena Bertelli Bianchi]

10 hours ago, Tyler Purcell said:

I haven't tested 35mm version yet, but with 16mm we saw no difference outside of it not having the constant remjet removal problems we found on the older film. Unfortunately, we can't get 35mm short ends of the new stock yet, but the moment we can, I will be buying some and testing on 35mm with a chrome pressure plate. The 16mm cameras seem to not be as effected with the halation issues, as the 35mm cameras with their chrome plates. 

the halation issue I was talking about was produced with a 416 😞

I worked with both and I noticed the same issues...

[Marcel Zyskind]

I'm shooting a film on 16mm with the new AHU stock at the moment with a 416 as A camera and XTR Prod and SR3 as B and C cameras. I find that on the 416 there is a lot more emulsion build-up and a lot more hair in the gate than previously. XTR and SR3 don't seem as affected, but are used a lot less. I'm mainly on the 416. 

[Aristeidis Tyropolis]

10 hours ago, Marcel Zyskind said:

I find that on the 416 there is a lot more emulsion build-up and a lot more hair in the gate than previously. XTR and SR3 don't seem as affected, but are used a lot less. I'm mainly on the 416. 

You have any pictures of the build-up in the gate? Kind of worried on the cleaning amount work needed on the gate between 100ft. daylight spool reloads.

Edited November 19 by Aristeidis Tyropolis

[Elena Bertelli Bianchi]

11 hours ago, Marcel Zyskind said:

I'm shooting a film on 16mm with the new AHU stock at the moment with a 416 as A camera and XTR Prod and SR3 as B and C cameras. I find that on the 416 there is a lot more emulsion build-up and a lot more hair in the gate than previously. XTR and SR3 don't seem as affected, but are used a lot less. I'm mainly on the 416. 

Personally I didn't noticed any difference when it comes to hair/gate dust -I've also been shooting with the 416. Out of curiosity, are you using the original (chromed) pressure plate or have you "darkened" one in some way?

[Gautam Valluri]

Is it still possible to order remjet stock from Kodak in Europe or is it all AHU now? 

[Aristeidis Tyropolis]

3 hours ago, Gautam Valluri said:

Is it still possible to order remjet stock from Kodak in Europe or is it all AHU now? 

I know Silbersalz only sells AHU now just got off the phone, and it's what I head from Andec as well (but not sure) - Waiting on an email from Haghe films on that as well.

[Marcel Zyskind]

14 hours ago, Elena Bertelli Bianchi said:

Personally I didn't noticed any difference when it comes to hair/gate dust -I've also been shooting with the 416. Out of curiosity, are you using the original (chromed) pressure plate or have you "darkened" one in some way?

All original plates. It’s working better since we started to nose grease the pressure plate. Believe it or not. 

[Marcel Zyskind]

12 hours ago, Gautam Valluri said:

Is it still possible to order remjet stock from Kodak in Europe or is it all AHU now? 

Kodaks entire European stock in Germany is now AHU

[Elena Bertelli Bianchi]

8 hours ago, Marcel Zyskind said:

All original plates. It’s working better since we started to nose grease the pressure plate. Believe it or not. 

good idea, love old tricks, any consequences on the image? Which ratio are you shooting on? 
 

and yes it’s all AHU now… I mean, I have nothing against the AHU technology, especially if it’s greener (still have to understand how), I just noticed a difference in quality and it’s weird for kodak, since everything used to be kinda perfect

Edited November 20 by Elena Bertelli Bianchi
Typos

[Simon Wyss]

Can I recommend black velvet around the pressure plate?

[Aristeidis Tyropolis]

2 hours ago, Elena Bertelli Bianchi said:

I just noticed a difference in quality and it’s weird for kodak

What kind of difference?

[Gautam Valluri]

12 hours ago, Marcel Zyskind said:

All original plates. It’s working better since we started to nose grease the pressure plate. Believe it or not. 

Did you seriously apply nasal sebum on the pressure plates? 😄

Is there reliably sufficient supply lol.

[Elena Bertelli Bianchi]

6 hours ago, Aristeidis Tyropolis said:

What kind of difference?

If you read the first post you'll find them! 🙃

[Aristeidis Tyropolis]

39 minutes ago, Elena Bertelli Bianchi said:

If you read the first post you'll find them! 🙃

Read it, my apologies. Wondering now if these findings extend to 16mm daylight spools as well.  Really hope you were just unlucky.

Let's see how people's reports extend through 2026...

Also curious now if Bugonia and One.Battle.After.Another was with AHU stock.

[Elena Bertelli Bianchi]

1 hour ago, Aristeidis Tyropolis said:

Read it, my apologies. Wondering now if these findings extend to 16mm daylight spools as well.  Really hope you were just unlucky.

Let's see how people's reports extend through 2026...

Also curious now if Bugonia and One.Battle.After.Another was with AHU stock.

I hope so... 

Regarding Bugonia and OBAA, the shooting period make me think it was the old stock... Kodak supplied AHU stock to some productions before it was officially released. In the article I mentioned before a few of them are listed, but there's no mention of either Bugonia or OBAA. We are talking about very appealing names to include in an article about their new product so I think it was old stock but who knows...

[Aristeidis Tyropolis]

We do know for a fact that Kodak was sampling AHU for sure for quite a long time before official release and some big name productions did use it.

I have accumulated quite a few rolls of remjet stock, with which I will start my b-roll shooting + camera tests soon, but then how valid would my tests be as afterwards as I'll be getting AHU stock...

Edited November 20 by Aristeidis Tyropolis

[Tyler Purcell]

AHU was being sampled for most of 2024, but they had limited quantities. Most films wouldn't want to switch mid-shoot to something they hadn't tested.

[Elena Bertelli Bianchi]

1 hour ago, Aristeidis Tyropolis said:

We do know for a fact that Kodak was sampling AHU for sure for quite a long time before official release and some big name productions did use it.

I have accumulated quite a few rolls of remjet stock, with which I will start my b-roll shooting + camera tests soon, but then how valid would my tests be as afterwards as I'll be getting AHU stock...

I know that feel... DPs from all over the world please give us a feedback!

Edited November 20 by Elena Bertelli Bianchi

[Frederick Knauf]

"I mean, I have nothing against the AHU technology, especially if it’s greener (still have to understand how), I just noticed a difference in quality and it’s weird for kodak, since everything used to be kinda perfect."

Elena,

AHU stock is "greener" in that carbon is no longer being used in the film's AHU.  Once conversion is completed, all labs could skip the rem-jet wash step in their process saving both power for the pumping of water, the water itself, which in some areas of the world is quite expensive, and both the costs of dealing with the filtration of the water effluent and the waste water itself from that rem-jet step. 

In terms of manufacturing of the base and the emulsion coated film, there are similar savings as rem-jet was a carbon slurry that was coated onto the backside and was prone to coagulate meaning that there was a high cost in filteration and those filters would be landfilled.  The present AHU removes those filters from being created, purchased, and employed, meaning energy savings when you look at the entire material flow to what is being used to manufacture these wonderful films.

In terms of material coatability (consistency in coating), the AHU layer coating process is far more consistent than that of the rem-jet, which was prone to streakiness, lines and a mottle-like pattern.  The new backside coating being applied to the backside of the base also coats with far greater consistency and requires both less water and fewer filter changes, meaning that waste produced in the base making process is reduced.  All these point to savings in material and power use meaning a greener planet.

 

[Simon Wyss]

Dear Mr. Knauf

You’re speaking of a new backside coating being applied to the backside of the base. I find that to be in contradiction to an Anti Halation Undercoat, a lightproof layer on the frontside of the base, underneath the photographic layers. Can you please clarify?

[Mark Dunn]

The AHU is under the emulsion, over the subbing layer- the new anti-static coating is on the outside of the base.

[Tyler Purcell]

I just wanted to post a follow up. My initial post about the stock working was with my own cameras, which are very well tuned because we shoot a lot of stuff. 

Since my early post in November, I have received 4 cameras, two Aaton's and 2 Arri SR's with issues directly related to AHU stock. 

All 4 of them work fine with Remjet, zero issues. I tested them and they are flawless. 

With AHU stock, we get back side scratching on all of them. We also have instability issues within the Aaton cameras specifically. I have done more scratch mitigation work than I've ever done before on these cameras. It seems like perhaps, the AHU stock creates more friction. 

I have noticed the perforation holes also deflect easier, this is an issue I saw directly on the Aaton cameras with penetration on the lower side of the spectrum, something I use to do purposely to keep the quiet. Now you can't do that trick anymore, you have to run penetration up much higher. The AHU stock is thinner, not much but it is. I don't think the thickness is necessary the problem, but I do think the stock flexes MUCH MORE than the Remjet stock, you can feel it when you work with it as well, it just feels like a lighter weight material. I think the carbon coating of the remjet made the film deflect less. 

I will do more scientific studies on this shortly, but I purchased some AHU stock for testing these cameras and it took a lot of work to get them not to scratch. Now I need to test every camera with AHU, which is expensive because it has to be NEW stock. 

[Simon Wyss]

Misunderstood, Mark. Thank you

Tyler, I think that the behaviour is clearly a function of the black backing no longer there. The soot-gelatine back coat is something different from the very thin anti-static protective layer which doesn’t consist of gelatine. Regarding the perforation it would be interesting to know whether Kodak punches intermittently or continuously. With 16-mm. stock, if Kodak notes REDUCED TOLERANCE PERFORATION, you know it’s step punched. With 35-mm. films we’re once more left in the dark. Hole edges can come out a little upset. Unfortunately carbide tooling is used on the drum perforators, not resharpened soon enough. These wear down as well as steel ones, only slower.

Carbide can be topped up. 384 parts per heart, it takes Kodak a month to finish a heart. They have a number of them. A slower 35 Bell & Howell perforator has 8 punches and an 8-holes die. Plus the pilot pins. Refurbished within hours.