Kodak Aerocolor IV Film Review

Kodak Aerocolor IV 2460, sold as SantaColor 100, Luminar 100, Film Electra 100, and Film Washi X, is a fine-grained medium contrast colour negative film with a clear base available in 35mm only.

For this review, I’ve tested this film in multiple cameras (including XPan, which generates the largest negative on this emulsion) and in various lighting conditions.

My Aerocolor IV test rolls were rebranded as SantaColor 100. They were re-spooled and packaged by Camera Rescue, a Finish film camera repair business. They were the first to bring this existing film to the market, though, as you probably understand by now, this film is sold under many names.

To be clear, only Luminar 100 and Film Electra 100 directly name their source emulsion, Kodak Aerocolor IV 2460. But given this film’s unique look, clear base, and the brands’ passing mentions of a colour surveillance film manufacturer with a box speed of ISO 100, it’s reasonable to assume that all brands mentioned above use the same emulsion.

Kodak Aerocolor IV is not Kodak Aerochrome.

Both Aerocolor and Aerochrome are colour areal surveillance films made by Kodak. However, the films’ looks and prices differ significantly.

Aerocolor is a true-colour film; the prints and the scans you’ll get from it will look photo-realistic (adding only physical characteristics of the film itself, like the grain and the chemical colour balance).

— from Kodak Aerocolor IV technical datasheet.

Aerochrome, on the other hand, is a false-colour film (like Lomochrome Turquoise and Lomochrome Purple) that renders non-complimentary colours. With Aerochrome, you can expect cotton-candy-coloured trees, black water and deep-blue skies. It is a completely different, discontinued emulsion that now sells as expired for hundreds of dollars. It is also difficult to expose correctly (I have a guide on how to do that).

— from Kodak Aerochrome III technical datasheet.

Kodak Aerocolor IV: a technical areal surveillance film; still in professional use in 2023.

Kodak Aerocolor IV 2460 is still made fresh. However, it’s only sold in bulk. According to Camera Rescue’s IndieGoGo page for SantaColor 100, the minimum order is equivalent to 15,000 rolls of 35mm.

Brooklyn Film Camera suggested that the demand for this film’s technical applications remained sufficient for production for years despite the modern, seemingly superior alternatives. In their video review, BFC suggested that the cost of upgrades still outstrips the price of development.

— Kodak.

Aside from being packaged specifically for surveillance tools and film processors, Aerocolor IV’s specialties are wide exposure latitude/dynamic range (up to ~10.5 stops), scratch-resistant emulsion, and a maskless negative that needs no colour interpretation after processing — which may produce more accurate reproductions, if scanned correctly.

In this review, and across most labs, this film is likely to get developed in C-41 at 39℃/102℉ for 3½ minutes. Aerocolor IV datasheet has a variety of processing times and temperatures with 38℃/100℉ for 5’15” (high-contrast) as the default and 38℃/100℉ for 3’15” as the lowest contrast option. When metered as an ISO 100 film and developed normally (39℃/102℉ for 3½ minutes), this film produces medium-low contrast with fine grain. You can experiment with lower contrast/finer grain by developing it at 38℃/100℉ for 3’15” at home and metering at EI 80.

Grain structure, resolution, and sharpness.

When developed normally, Aerocolor IV’s grain is quite noticeable, particularly when scanned well and displayed on large screens or in print. It becomes more prominent in the shadows or when the film is under-exposed.

But when an adequate amount of light is given to the emulsion, most of the fuzziness goes away. The grain that remains appears sharp and may be distracting in some instances, but the images still appear to have a lot of resolution.

Kodak’s datasheet for Aerocolor IV lists its granularity value at RMS 8.5 — when exposed at EI 80 and developed in C-41 for 3’15” at 38℃/100℉. This implies that this film’s grain is exceptionally fine and that it may carry even more information than the famously detailed Fujifilm Velvia 50.

However, to achieve the 8.5 RMS granularity, you’ll need to follow the above development times, temperatures, and metering guidelines; your lab may not be able to do that for you. For normal development times, consider over-exposing your film slightly to minimize the grain’s prominence.

It’s also worth noting that RMS is not a particularly precise measure of film’s graininess; Kodak has somewhat recently switched to the Print Grain Index to measure its emulsions’ perceived textures. Instead of using scientific instruments to measure diffuse granularity, PGI collects a set of surveys to determine the average perception of grain from the onlookers.

Still, even with a typical processing temperature/times, Aerocolor IV may yield exceptional results. This is particularly evident in larger negatives; unfortunately, for Aerocolor IV, there’s no medium or large format and thus, the largest exposure area can only be obtained in a panoramic camera:

Dynamic range.

As promised in the datasheet, Kodak Aerocolor IV handles high-contrast scenes well. Before I updated this article, I used the characteristic curve for 4’15”, which demonstrated about nine stops of dynamic range. However, in this edit, I am substituting it for another graph that uses the 3’15” at 38℃/100℉ in C-41. This is the lowest-contrast, finest-grain process which demonstrates the results this film can achieve in ideal conditions.

The characteristic curve for Aerocolor IV (low-contrast) is nearly identical to the medium-contrast curve (which is what you’re likely to get when developing this film normally and metering at EI 100). However, the low-contrast process shows less maximum density and less contrast with a slight extension of its dynamic range to maybe 3.15 lux-seconds or about 10.5 stops of dynamic range.

Thus, if you need your film to show finer grain and an extra stop of dynamic range, you will need to develop it for 3’15” at 38℃/100℉ and meter at EI 80. But in most cases, I think that nine stops with an RMS ~13 granularity will work fine with this emulsion.

Scanning Aerocolor IV.

Aerocolor IV does not have an orange mask. This unique property makes this film relatively easy to scan in some instances and hard in others.

Common colour negative film’s orange mask makes it up to the software, the user, or the darkroom printer to interpret the colours encoded in each frame. The mask simplifies production for the manufacturer as it counters chemical impurities. It is a standard way to encode analogue colour image information in a negative since the mid-20th century when the process was invented and popularized.

Clear-base films have also existed for a long time, slide films being the prime example. An orange mask would be unacceptable for projection, which is when manufacturers spend additional resources to combat the impurities. In the case of Aerocolor IV, there are no projection requirements (this film is not suitable for cross-processing as a slide/positive film); instead, Kodak decided not to use an orange mask in order to lift the burden of colour interpretation during printing and scanning.

If you scan your Aerocolor IV as a positive, to get the colours exactly as they are encoded on the emulsion, you will only need to invert it and remove base fog by equalizing your image. You can do this in Adobe Photoshop or any image editor of your choice that lets you control curves.

Traditional and some new colour film scanning software may not expect negatives without an orange mask. This is why you may need to spend more time adjusting your images when using those tools. This isn’t ideal; I recommend you ask your lab to scan this film as a slide or prepare a digital negative yourself at home and then invert it as described above. An improvement in colour accuracy and fidelity is practically guaranteed if you avoid having your software guess the colours and take control over your images.

Note that the “clear base” negative (or a negative without integral colour masking, as Kodak describes it in the datasheet for Aerocolor IV) does not necessarily mean that the film is completely transparent in areas where it should appear black. Instead, this means that the base colour should have no influence on colour information in the image once it is subtracted (this is what I meant above by removing the base fog via equalization).

And since there is some colour in the film base, processing Aerocolor IV as a slide film will yield a strong tint to all your images. This can be easily edited out using the same equalization method, but you will not be able to project your images as slides.

— Kodak.

Due to its unusually thin base (0.132mm), lack of markings, and texture, Aerocolor IV can be frustrating to scan. It dries very flat, which is nice for achieving; however, it can be impossible to tell the emulsion side:

Other films will give you a hint as to which way to put the film into your scanner by showing letters and numbers in the margins that you can use to identify the emulsion side (they will appear normal, not mirrored). Most will appear shinier on the emulsion side or curl away from it. Aerocolor IV looks identical no matter how you hold it; in practice, I had to rely on memory and the lettering, if present. Although you may be able to reverse your frames digitally if you’ve noticed that you’ve scanned them wrong-side-up — the film base is so thin there may be no difference between either side in scanning resolution.

Aerocolor IV colours.

Most of the SantaColor 100/Aerocolor IV scans in this article are all colour correction-free. They are direct, equalized inversions of the negatives. The colours may still vary depending on the scanner hardware (I used PrimeFilm XAs), your device, and image compression — but not as much as with other films that rely on human or machine interpretation.

If you scan your Aerocolor using the methods described above, expect your film to show medium-low contrast and extra emphasis on reds, as the rest of the colours appear natural with a tendency to cool in the highlights and warm up in the shadows. Of course, don’t let that stop you from adjusting the colours of your work to your needs and preferences.

A word on grey balance. One of the most challenging aspects of correcting colour negative film is achieving grey balance across all exposure zones. This means ensuring that whites are 100% white, mid-greys are grey (and not any shade of green/red/blue), and blacks are 100% black.

For example, Kodak Ektar defaults to navy blue at its black point, which needs to be corrected before printing. The advantage of Aerocolor IV (perhaps due to the absence of the orange mask) is a perfect grey balance across the frame in most well-exposed, well-scanned images (when inverted using the methods described above).

However, a bias toward greens can still be seen in low-contrast, overcast (cool light) scenes and in over-exposures.

How much do Aerocolor IV films cost, and where to buy them.

If you want to buy this film in bulk, prepare to dish out about $150,000 directly to Kodak. Thankfully, there’s no need to do this as the above-mentioned brands have done that and the difficult job of spooling it into film canisters for you.

As of this writing, the prices range from $15 to $25 per roll of 35mm Aerocolor IV. You can find them all at this link.

❤ By the way: Please consider making your SantaColor 100/Aerocolor IV/Luminar 100/Film Electra 100/Film Washi X film purchase using this link so that this website may get a small percentage of that sale — at no extra charge for you — thanks!