New (2025) Portra 160 120 ESTAR base vs. old one on acetate

[Oldwino]

The only difference I’ve noticed is a seemingly weaker anti-halation layer. There is more ”bleed” around very bright areas than I remember from the past. I have also read that the AH layers are a bit of an issue on the new base material (but I dont know if that is true).

 

[Lachlan Young]

Having said that, some materials have a better mechanical memory than others. Roll film is (surprise surprise) rolled up, so the film tends to 'remember' the curl.

This is the core-set property - CTA takes on and loses core-set more readily than PET, so PET (if it's engineered to be flatter) will load initially more easily (stiffer than CTA) but may be a little trickier to manipulate for some as they push it to the core. That being said, I've found the PET Kodak CN films easier to load on Jobo 2502 reels than the CTA versions. In comparison, PET films intended to be generally loaded on large reels in significant quantities (e.g. aerial recon or cinema print) are engineered to retain a consistent curl to make them less troublesome in their intended roles. Bob Shanebrook goes into a lot of detail on all this in his book.

 

[pentaxuser]

I doubt it has much to do with the base material. 120 and sheet film is coated on both sides with gelatin. One side obviously for image-making, and the other side to counter the curl that you'd inevitably get if you were to coat only one side. So "counter-curl", in a way. The interactions between these coatings would affect reel-loading characteristics as well as curl characteristics. Much more so than the actual base material that's inside the sandwich.

Having said that, some materials have a better mechanical memory than others. Roll film is (surprise surprise) rolled up, so the film tends to 'remember' the curl.

Thanks It was just the respondent's comment on it being easier then harder as he loaded the reel towards the centre that piqued my curiosity. So the reason is still a bit of a mystery

pentaxuser

 

[halfaman]

After suppressing a rebellion on my scanning computer (HDD corruption), I was able this weekend to scan some of the new Portra 160 with the ESTAR base. It was really easy to handle, no curl at all, and results were as nice as always with a similar ammount of (little) effort. Business as usual for me.

My problem with the Jobo reel could be that, being the film now thinner than before, the leader get stuck easier than triacetate version, and I can misunderstood this with reaching the end of the reel.

 

[koraks]

being the film now thinner than before

Are you sure it really is thinner?

 

[halfaman]

Are you sure it really is thinner?

In this development batch I have both versions, with triacetate and polyesther, and it was very obvious for me just touching both.

 

[koraks]

Old Portra 400 datasheet

https://business.kodakmoments.com/sites/default/files/files/products/e4050_portra_400.pdf

Recent Portra 800 datasheet

https://www.kodakprofessional.com/sites/default/files/2025-07/e4040.pdf

Not a whopping difference.

Note that the difference between 0.004" and 3.94mil may be even less than the 0.10/0.11mm difference when expressed in metric.

 

[halfaman]

Old Portra 400 datasheet

https://business.kodakmoments.com/sites/default/files/files/products/e4050_portra_400.pdf

View attachment 402938


Recent Portra 800 datasheet

https://www.kodakprofessional.com/sites/default/files/2025-07/e4040.pdf

View attachment 402939

Not a whopping difference.

Note that the difference between 0.004" and 3.94mil may be even less than the 0.10/0.11mm difference when expressed in metric.

They feel very different while loading the reels in complete darkness, and ESTAR version has significant lower stiffness.

 

[mshchem]

They feel very different while loading the reels in complete darkness, and ESTAR version has significant lower stiffness.

So is the ESTAR version less likely to curl? Not so much after processing, I'm thinking more about loading the reels. Sometimes I have had issues loading Jobo reels with 120 film that's been sitting a while and has taken on a "set". The film end first in the reel will walk off the reel channels.
I haven't had much of this of lately, it might have been more related to the old age of the film???

 

[DREW WILEY]

Regardless of the base, I alway firmly reverse curl or bend the leading edge of the film before reeling it, plus clip its corners to prevent binding.

 

[halfaman]

So is the ESTAR version less likely to curl? Not so much after processing, I'm thinking more about loading the reels. Sometimes I have had issues loading Jobo reels with 120 film that's been sitting a while and has taken on a "set". The film end first in the reel will walk off the reel channels.
I haven't had much of this of lately, it might have been more related to the old age of the film???

Yeah, old age film tends to curl a lot. I developed recently a Vericolor roll for a friend and there was some struggle to put the damm thing into the reel (came almost completely blank on top of that).

This new ESTAR Portra 160, none. Very easy to thread into the reel.

 

[mshchem]

Yeah, old age film tends to curl a lot. I developed recently a Vericolor roll for a friend and there was some struggle to put the damm thing into the reel (came almost completely blank on top of that).

This new ESTAR Portra 160, none. Very easy to thread into the reel.

Sounds good. ESTAR is the best substrate going. Thanks for your reply!