Text & Photo: Bjørn Joachimsen
In the autumn of 1992, I was working in the darkroom filled with expectations beyond the ordinary. For the first time, I had exposed and developed the brand new Ilford Delta 100 Professional film and was preparing to make enlargements. As the print gradually emerged in the developing tray under the red light, I saw a picture quality I had never experienced before from an ISO 100 film.
Gran Canaria. Pentax 645Nii and Ilford Delta 100. Red filter 25. ©Bjørn Joachimsen.
The enlargement I created on a 24x30cm Ilford Multigrade paper from a 24x36mm negative astounded me. The grains were literally invisible, and the sharpness was at a completely different level than anything I had seen from an ISO 100 film so far.
After decades of noticeable, yet minor innovations in black-and-white film development, a significant leap occurred between 1986 and 1992. It was Kodak that initiated this new era in film technology when they launched Kodak T-Max 100 and T-Max 400 in 1986. Ilford responded with Delta 400 in 1990, followed by Delta 100 in 1992. A few years later, in 1998, Ilford Delta 3200 was introduced, in response to Kodak T-Max 3200, which was already available on the market.
Core-shell™ technology
The major difference in these new films lies in the grain technology. Due to a different production method, the grains in Delta 100 and similar films capture more light relative to their size. This means that, in practice, the film, despite being ISO 100, will yield grain and sharpness comparable to a classic ISO 50 film. Ilford Photo calls this emulsion technology Core-shell™. When it comes to image results, it possesses characteristics very similar to Kodak's T-Max films, although the technologies are not identical.
Key Features of Ilford Delta 100
Ilford Delta 100 offers several advantages that make it a popular choice for photographers:
Fine Grain: Delta 100 is known for its exceptionally fine grain structure, which allows for high-quality enlargements and detailed images.
High Resolution: The film has excellent sharpness and detail resolution, making it suitable for landscapes, portraits, and any situation where clarity is essential. Resolution is 160 lp/mm.
Wide Exposure Latitude: It has good exposure latitude, meaning it can handle overexposure well.
Versatility: It is suitable for a variety of photography styles, including portrait, architecture, and landscape.
Compatibility with Various Developers: Delta 100 can be processed in a range of black-and-white developers. You will achieve medium contrast with standard development in typical developers.
Færder National Park. Norway. Pentax 645N. Ilford Delta 100. ©Bjørn Joachimsen
Applications
Ilford Delta 100 Professional has many applications and is primarily suited for situations where the photographer desires high resolution and sharpness. Due to its moderate sensitivity, it is often necessary to use a tripod when photographing. Atripod will be advantageous to take full advantage of the film's high resolving power. Personally, I have used Delta 100 for a variety of photographic applications, but primarily for landscapes, architecture, and portraits. I have also employed it for documentary photography, but mainly in 135 format and in daylight during the summer months. In landscape photography, I have primarily used Delta 100 with medium format cameras and in the 120 film format. This combination gives astounding results, and the details in the finished images are incredible. This is a good choice if you wish to create large enlargements while also wanting a photographic look where the grain is very discreet.
Słowiński National Park. Poland. Pentax 645. Ilford Delta 100. Red filter 25. ©Bjørn Joachimsen.
Using Optical Filters
Delta 100 has a standard spectral sensitivity, allowing you to achieve exciting effects by using yellow, orange, or red filters on the lens in landscape photography. This will have a particularly pronounced effect when photographing under a clear or partly cloudy sky. In such situations, you will find that the blue sky (and all other blue tones in the scene) is rendered with a darker grey tone than what an unfiltered exposure would provide. In these cases, I would recommend using an orange filter (22) or a red filter (25). You can also achieve interesting effects by using a green filter when photographing foliage. Anything green in the scene will be rendered with a lighter grey tone than would be the case with an unfiltered exposure. Photographs taken with infrared filters (higher than 650 nm) will hardly yield any exposure on the film and are therefore unsuitable.
Remember that you must adjust the exposure when using filters if you are measuring light with an external light meter.
Exposure and Development
The nominal sensitivity (also known as box speed) is, as is well known, ISO 100. However, with many developers, you will not achieve this sensitivity if you wish to have good reproduction of details in the shadows. The ISO you choose to set your light meter to largely depends on which film developer you intend to use. This is, of course, a relationship that also applies to all other black-and-white films. If you use Ilfotec DD-X, you should be able to achieve very good results by exposing at ISO 100. You can also push the film with good results, but preferably not higher than ISO 200. When pushing, you will achieve slightly less detail in the shadows, but in return, you will have higher contrast in the midtones and highlights. If you use Ilfotec ID-11, you will achieve grain and sharpness that are comparable to the results you get with DD-X, but you will have lower sensitivity as well as lower contrast in the shadows. With such a developer, it would be beneficial to expose at ISO 64-80, or even lower. Ilfotec HC will provide a marginally lower sensitivity compared to DD-X.
Delta 100 and the other films in the same family require more precise exposure and development to achieve good results compared to films with classic grain technology. The exposure latitude is somewhat narrower than when using, for example, Ilford FP4+. IIn situations where possible, I recommend using a handheld light meter with incident light measurement to achieve correct exposure.
| CHOOSING THE BEST ILFORD DEVELOPER for ILFORD DELTA 100 PROFESSIONAL | ||
| Liquid | Powder | |
| Best overall image quality | ILFOTEC DD-X | ID-11 (Stock) |
| Finest grain EI 100/21 | ILFOTEC DD-X | PERCEPTOL (1+1) |
| Finest grain EI 50/18 | ILFOTEC DD-X | PERCEPTOL (Stock) |
| Maximum Sharpness | ILFOTEC HC (1+15) | ID-11 (1+3) |
| Maximum Film Speed EI 200/24 | ILFOTEC DD-X | MICROPHEN (Stock) |
| One-Shot Convenience | ILFOSOL 3 (1+14) | ID-11 (1+1) |
| Economy | ILFOTEC LC29 (1+29) | ID-11 (1+3) |
In my opinion, Ilfotec DD-X is the best developer for Ilford Delta 100.
You can download the technical data sheet (PDF) for Ilford Delta 100 Professional here: https://www.ilfordphoto.com/amfile/file/download/file/3/product/679/
You can download the Film Processing Chart (PDF) for Ilford Delta 100 Professional here:
https://www.ilfordphoto.com/amfile/file/download/file/3/product/679/
Gran Canaria. Pentax 645Nii and Ilford Delta 100. NiSi ND 8 filter. ©Bjørn Joachimsen.
Long Exposure Photography
Photographing with long shutter speeds can create fascinating effects, and you can easily achieve this with Delta 100. However, all photographic films have an "inbuilt" resistance to excessive exposure, which becomes noticeable when you are exposing for long durations. This "long exposure effect" is often referred to as Reciprocity Failure or the Schwarzschild effect. This means that when you use long shutter speeds, typically longer than 2 seconds, you need to add extra exposure time for the result to be correct. The long exposure effect works in such a way that the deviation increases the longer the exposure time you use. You can utilise a formula or a table to calculate the correct exposure in these situations, but the simplest method is to perform the calculations using a Reciprocity Timer App (iOS) or similar smartphone apps.
Adjusting for reciprocity failure with Ilford Delta 100.
| Measured time | Adjusted time |
| 2s | 2s |
| 4s | 5s |
| 8s | 13s |
| 30s | 1m 12s |
| 1m | 2m 53s |
Available formats
Ilford Delta 100 is available in several formats, including:
135 format (36 exposures)
120 format (medium format)
4x5 inches (sheet film)
8x10 inches (sheet film)
Through Ilford Photo's annual ultra large format (ULF) sheet film campaign, the film can also be purchased in 5x7 inches, 16x20 inches, 11x14 inches, 8x20 inches, and several other formats.
If you haven't tried Ilford Delta 100 Professional before, I would recommend giving it a go. Feel free to use your sharpest lenses and a tripod when photographing, so you can make the most of the film's unique characteristics.
Gran Canaria. Pentax 645Nii and Ilford Delta 100. ©Bjørn Joachimsen.
