Anti-halation layers

[Tim Gray]

Why does Kodak HIE not have an anti-halation layer? Is there some technical reason? Are there any other non-IR films that don't have this?

 

[nicolai]

I don't know why it doesn't have an anti-halation layer, but it's not a technical issue that applies to IR film in general, though it may be one that applies to their specific process. The only other one I'm aware of was the somewhat-recently discontinued "Aura" version of Maco 820c.

 

[Jerevan]

The chinese-made Lucky (non-IR) films are supposed to lack anti-halation. Never used them myself so I can't comment further.

 

[fschifano]

The chinese-made Lucky (non-IR) films are supposed to lack anti-halation. Never used them myself so I can't comment further.

The Lucky Pan films do have some anti-halation properties, but it is not nearly as effective as the coatings on most other films. As to why Kodak does not use an anti-halation coating on its HIE film, I haven't a clue.

 

[boyooso]

As I understand, the anti-halation coating helps prevent the scattering of light when the image from the lens hits the film.

I just looked up the halation on dictionary.com

a blurred effect around the edges of highlight areas in a photographic image caused by reflection and scattering of light through the emulsion from the back surface of the film support or plate.

I suspect the Kodak HIE doesn't have it order to give a more distinct look(more glowy), something different, I really like it! I wish the Aura was back too.

FWIW, the wonderful Kodak Pan Masking film didn't have it either.

Corey

 

[Tim Gray]

I always assumed HIE and EIR catered to scientific/military/industrial uses and not to the "art" crowd. That's why I was wondering if there were an actual reason for the lack of the layer. It certainly does give the film a unique look which I like, but it's not necessarily the reason it is the way it is.

 

[PHOTOTONE]

The lack of a strong anti-haliation layer on the Lucky films results in light scatter in the highlights that makes the image softer, and confused looking in the highlights. While this vintage look can be used to advantage for some types of images, as a general-purpose film, the Lucky films are somewhat problematical for me because of this.

 

[Photo Engineer]

AH layers were used back in the early part of the last century. There were AH glass plates. All of the 'old' films you think of nostalgially have AH layers or AH dyes in them dating from about 1900 or so. The AH dye commonly used back then included tartrazine, a yellow dye that washed out in water and was used because the films were only blue sensitive. The next dye used was orange in color due to ortho films, and now they use a rather black or grey dye for pan sensitive films.

So, to get to IR films, what color dye would you use in an AH layer for IR? Well, you need an IR absorbing dye. So, with tongue partly in cheek I suggest that the dye is there, but unless you can see in the IR, you can't see the AH layer... Or that the scatter by IR is not significant in IR films due to their wavelength?



PE

 

[Scandium]

IR Anti-halation

Kodak has used anti-halation base material for IR in the past. I got some bulk surplus military/industrial IR 35mm film in the mid 70s from a vendor of short ends. It had Kodak edge marks, Bell and Howell perfs, and a triacetate base that was dyed to absorb both some visible and nearly all nearly all red/IR from ~ 720nm to 1000nm (I tested it on a spectrophotometer). It may have also used a soluble dye between emulsion and base. I wasn't able to determine that.

Visually, a clear strip of film looked just a little darker grey than clear Tri-X. Speed was approx. the same as HIE, but grain was much more along the lines of Tri-X. The dyed base was effective as negatives showed very little of the highlight blooming that HIE has. I called Kodak about getting some more and was told it was probably a special order material so they had no more to sell. Pity, I liked it better than HIE.