This post collects some comments from online sources and seeks to demonstrate those comments when looking at the details of two Ilford 400-speed B&W films: Ilford HP5+ vs Ilford Delta 400. I've wondered myself why have two 400-speed products? What is the difference? How / if those differences show in the results?
Part of my own "return to film" is exploring the different film types. Today's film is primarily premium emulsions, shot in premium cameras, unlike back in the day when you'd grab a disposable camera at the gas station for an afternoon at the beach. The available film types also change somewhat regularly. For example, Fuji has both retired and restored Neopan ACROS 100 in the past 10-years. Fuji also just removed their color Pro 400H in all formats effective January 2021.
For the term film 'emulsion', this refers to how the silver halide grains are suspended in a gelatin colloid. Different film types, aka stocks, use different shapes of the silver halide grains, creating different 'looks' in how the film looks in terms of sharpness and the tone of the black and white contrast of the image.
This comparison is based on two Ilford stocks. If you're unfamiliar with Ilford, Ilford Photo started as Britannia Works Company in 1879 in the town of Ilford, England. The company changed their name to Ilford Limited in 1902. They're a leader in black and white films for now more than 100 years. Their HP5 line has a history stretching over 70-years. The full name of HP5+ is "Hypersensitive Panchromatic" and the latest version was launched in 1989. HP5 uses a more traditional cubic grain structure that delivers a classical B&W photography look.
Example 1 - Ilford HP5+Scanned from Ilford HP5+ (shot at ISO 200)
EOS 1v, EF 35mm f/1.4L, 1/320 sec at f/5
Wrigley Field Marquee by
Paul Sager, on Flickr
Ilford Delta 400 is a newer film, started in 1990 and reformulated in 1994. Delta 400 is a "T-grain" film (Tabular grain), this is slightly modified from a conventional-grain film in the way the film’s silver content is dispersed. T-grain films (such as Ilford Delta, Fuji Acros, Kodak T-Max) have flat crystals whereas conventional-grain films (like Ilford HP5, Kodak Tri-X, Rollei RPX) have round crystals. The flatness of the crystals permits better light absorption per quantity of silver within the emulsion. The theory of T-grain film is that it should provide sharper images and finer grain when compared to a conventional-grain film of the same sensitivity.
Example 2 - Ilford Delta 400Scanned from Ilford Delta 400 (shot at ISO 100, expired 03/2006)
EOS 1v, EF 35mm f/1.4L, 1/160 sec at f/5
Wrigley Field There are differences too in the exposure latitude of the two films and the development process. The HP5 is considered as having more lattitude in being over- or underexposed, possibly up to 5-stops with acceptable results. The Ilford Delta 400 has less lattitude, whether purposeful or in error, more around just + (or -) 1-stop exposure.
Personally, I don't develop my own film. I'll defer to others for their experience and recommendations on the home development of these film types. In my results and preferences, both films benefit from +1 stop of exposure over their 400 'box speed'. For new film cameras, this can be done by adjusting the Exposure Compensation, or changing (overriding) the ISO setting, or assuring the meter reads +1 over the 0-mark of your light meter's recommendation.
Finally, before getting into the details of specific images, I also use colored filters with my B&W film. These filters don't just lessen the light reaching the film, they also impact the camera's meter. As a rule of thumb, the exposure should be adjusted by +1 for yellow, +2 for orange and +3 for red. I've been working on my technique now for a few years and the combined +1 for the film and +2 for the orange filter (+3 combined) is giving me the results I've been seeking, see the final Cloud Gate image below.
Example 3 - Ilford HP5+Scanned from Ilford HP5+ (shot at ISO 200)
EOS 1v, EF 35mm f/1.4L, 1/125 sec at f/6.3
Hot Stove Season This post isn't intended to be a 1:1 compare of the two films. Other than the Marquee images, above, that happen to have the same lens and camera and advertising on different days, I don't have many similar shots from the two films.
These initial Ilford H5+ images (examples 1, 3 and 4) look at images without a color filter.
Example 4 - Ilford HP5+Scanned from Ilford HP5+ (shot at ISO 400)
EOS 1v, EF 24mm f/1.4L, 1/40 sec at f/2.8
USS Cod - Galley Hopefully, the differences of the two films are subtle, if at all, when looking at these scanned and processed images. The scanned JPEGs are all processed in Adobe Lightroom v6 and the posted JPEGs are resized to 1600-pixels wide to embed into this UHH post. The shot above of the dinner plates on the submarine begins to get 'close enough' to see the film grain. We'll look more closely at the grain via 100% crops in some examples below.
Example 5 - Ilford Delta 400Scanned from Ilford Delta 400 (shot at ISO 400)
Canon AE-1, FD 24mm f/1.4L, shutter speed and aperture unknown
Bike The Drive Example 6 - Ilford Delta 400Scanned from Ilford Delta 400 (shot at ISO 400)
EOS 1v, EF 50mm f/1.8, 1/80 sec at f/9
1932 Studebaker / Route 66 Marker As mentioned earlier, I don't have images that were captured / created for the purpose of a review of the film grain. These next two examples are neither 'good' or 'bad' nor even very 'different' in terms of film grain. I do feel the Delta image is modestly finer grain, if you simply shoot at the box speed of the film. The lighting differences in each situation probably contribute more to the difference than the film type.
Example 7 - Ilford HP5+Example 8 - Ilford Delta 400Finally, the images below present results using colored filters. I've been learning and gaining confidence to really increase the overexposure adjustment when using these filters. My preferred / desired result is the final Cloud Gate image. The first USS Cod (example 9) is underexposed with way more grain than I could have achieved with another +1 stop of exposure. Example 10 has a bit finer grain of the Delta 400, but still I should have been upping the exposure based on the film and the filter being used. The Cloud Gate example 11 accomplished 3-stops (ISO-200 and +2EC). Going forward, I'll probably just load the film as ISO-50 rather than the combination of settings when using fresh Ilford Delta 400 and an Orange filter.
Example 9 - Ilford HP5+Scanned from Ilford HP5+ (shot at ISO 400)
EOS 1v, EF 24mm f/1.4L, 1/250 sec at f/5.6 and +2EC with dark red filter
USS Cod Example 10 - Ilford Delta 400Scanned from Ilford Delta (shot at ISO 400)
EOS 1v, EF 35mm f/1.4L, 1/640 sec at f/5.6, and +2EC with orange filter
San Jose Catholic Church Example 11 - Ilford Delta 400Scanned from Ilford Delta (shot at ISO 100)
EOS 1v, EF 35mm f/1.4L, 1/125 sec at f/6.3, and +1EC with orange filter
Cloud Gate