Side-by-Side • Kodak HC-110: Dilution B vs. Dilution H

In this first of a new series of articles, we take a look at how, and to what extent, using two different common dilutions of Kodak’s HC-110 black and white developer impacts the resulting film images. Our novel approach to this series hopefully will make it extremely easy to see and identify the differences — an approach we intend to bring to a number of comparisons in the months ahead.

New Series: Side-by-Side

Head-to-head comparisons of lenses, cameras, films, darkroom chemicals, and so forth are hardly new to the world of film photography web sites, podcasts, and videos; in fact it’s a well-trodden and familiar bit of territory. Regardless, there were still a lot of questions I had about a number of things that were best answered by a direct comparison, so I decided we should jump on the bandwagon to answer some of them.

Often, however, these comparisons are made between substantively different images — perhaps entirely different subjects, or the same subject photographed separately. I wanted to tackle it all a bit differently, and it started with my Kodak Retina camera collection.

The Retinas are compact, high quality cameras with excellent optics, and they’re highly serviceable. Despite their midcentury age, they can be relatively easily restored to full function, provided they’ve not been abused or damaged over the decades.

One of my favorite models, the Retina IIa Type 016, seemed like a great candidate for my idea: Place a pair of identical Retinas on a dual tripod bracket, and photograph the same subject, at the same time, the same way, triggering the cameras with a dual cable release. A second Type 016 was acquired and serviced (as all my Retinas are) by expert Paul Barden, the necessary components were obtained, and the result was this:

This dual camera rig will be the foundation of many of the articles planned for this series.

The Background

When I first started developing film at home, one of the first things I had to decide was which developer to use. Equipment, stop bath and fixer? Well, those are pretty consistent across the board, and there’s no real difference between, for example, Ilford’s fixer and Kodak’s. But developers are another matter. There are powders and liquids, one-shots and reusables, single-function chemicals and monobaths, one-step and two-step, some are cheap and some are not… It can be overwhelming to choose.

To help make my decision, I noted what was most important to me personally:

• Economy
  Stop and fix (as well as hypo-clear and surfactant) are pretty consistent in their price points, but developers vary quite a bit, and I wanted to make sure that what I chose was, in the end, going to result in a per-roll cost that was cheaper than using a lab — or there was little point in processing film at home.
• Shelf Life
  I very rarely hear people talk about or express any concern over shelf life, but for me, it was a major consideration. The moment you open a bottle of a liquid darkroom chemical, or mix a powdered chemical, the clock starts ticking. Whether it’s months, weeks, or even in some cases days, the chemical will eventually go bad. Because my shooting is sporadic and divided between black and white, color negative and color reversal films, it’s sometimes hard to use chemicals before they go bad. Not only would that be wasteful, but it would change the economics as well.

It goes without saying that I wanted a developer that provided good results with nearly any film, so I did my homework based on that and the two criteria above.

After creating spreadsheets to track per-roll cost estimates, I arrived at my choice: Kodak HC-110, a popular liquid developer usually used as a one-shot, meaning it’s mixed to process the roll(s) in a single developing tank, then discarded afterward.

HC-110 is economical, easy to use, and anecdotal reports suggest that an open bottle of HC-110 can remain viable for years — well past what Kodak’s data sheet suggests. Plus, it offers terrific results with virtually any film.

Blogger and podcaster Alex Luyckx has said he’s never met a film that doesn’t like HC-110, and my experience has been the same. I’ve processed pretty much every major black and white film with it (and many obscure ones too), and the results are consistently good.

If you’ve used HC-110, then you already know that you can use it at various different dilution strengths. Kodak’s data sheet has a table of them, and the dilutions are given letter designations: Dilution A, Dilution B, and so on. The film community has even created a number of unofficial dilutions, most notably, perhaps, Dilution H.

Dilution B is the one normally recommended for small tank hand processing, and it’s a 1:31 mix ratio (about 3% strength). Dilution H is exactly half the strength: 1:63 (about 1.5% strength). Conveniently, Dilution H development times are simply twice the length of Dilution B times (at least as a starting point, but it’s always worked well for me in practice) — half the strength, twice the time.* Easy.

Dilution H was (and is) appealing, because you use even less of the chemical, increasing economy considerably in exchange for more time in the darkroom. Being somewhat impatient myself, however, when development times for any given film get past the 12 to 15 minute mark, I usually use Dilution B to speed things along. The net-net is that probably 40% of the time, I use Dilution B, and 60%, Dilution H.

I’ve never noticed any real difference in the results. But then I kept reading Alex Luyckx commenting that Dilution B provides stronger contrast. Again, I never noticed there was a difference, but then, I also never looked.

And thus, the genesis of our first Side-by-Side, to see the differences (and the extent of those differences) for myself.

The Question

So then, if you’ve not guessed, our question for this Side-by-Side is straightforward.

Is there any measurable difference in the results between a specific film developed in HC-110 Dilution B, and the same film developed in Dilution H?

Let’s find out.

The Test

The black and white film I currently have for bulk loading is Ilford Delta 100, which has rapidly become my favorite film for 35mm shooting due to its exceptionally fine grain, and excellent tonality. While I’ve tended to favor traditional film emulsions and eschew modern ones like Delta and Kodak’s T-Max, the smaller negatives of 35mm film mean that I want the sharpest results and the finest grain I can get. After testing both Delta and T-Max, for me, Delta provides the best results, and works well with HC-110 developer.

I bulk-loaded two 15-exposure rolls and put them into the pair of Kodak Retina IIa Type 016 cameras, and set about shooting a range of scenes. I wanted to try and get some shots that would have both some good shadow areas and highlight areas so I could see the difference in detail that might be revealed by the different developer concentrations.

Once done, as already mentioned, the two identical rolls were souped — one in Dilution B, one in Dilution H. The Dilution B roll was processed for 6 minutes as per Ilford’s Delta 100 data sheet, and the Dilution H roll at 12 minutes, per the rule of thumb I already described. (I did look at the Massive Dev Chart to see if any Dilution H times were noted, but there were none; of course, that reference is community-sourced information, and as such, isn’t always completely reliable anyway.)*

After the negatives were dried, they were scanned. My normal workflow with my Epson V800 scanner is to scan with auto-exposure enabled, and all other settings off. Auto-exposure does a pretty decent job, I find, reducing the need to adjust brightness or contrast in Photoshop later on. But, all other automations are disabled, because they have a negative (pardon the pun) effect on the resulting images.

Because auto-exposure would skew the results of this test, of course, the negatives were all scanned twice — once with auto-exposure on, and a second time with it off. In the results below, some of each are provided.

The Results

So, what did we find out? Let’s have a look using an interactive image comparison. On desktop, use your mouse to move the center bar back and forth, and on mobile or tablet, you can do so with your finger. And please note that in all images, Dilution B is on the left, Dilution H is on the right. Also note that there are slight parallax differences between the two images, as you would expect given the setup of the two cameras.

While I took more photos than just these two, all of them yielded the same basic result. And as you will likely agree, there’s a very slight difference in the plain scans, but no real appreciable difference in the scans with auto-exposure enabled. Furthermore, I believe that all of these negatives, regardless of the scanning settings, could be brought to levels that are virtually identical during post-processing with Photoshop, Lightroom, or similar tools without any quality loss.

Next, I wanted to look at the differences in grain. For this, I took one of my images and zoomed-in on the high-res scan.

While I perceive a slight increase in grain in the Dilution H image, it’s unclear to me how “real” that result actually is. It could simply be the slightly stronger contrast I observed in Dilution H, or I could also pretty easily attribute what I observe here to slight variations in my focusing accuracy between the two cameras, although this was shot at f/8, and would have provided reasonable depth-of-field. Regardless, I wouldn’t characterize the difference as “dramatic” whatever its cause.

I was curious to understand whether my choice of film (Ilford Delta 100) had any impact, so I decided a second test was in order.

The Second Test

For the second test, I wanted to use a traditional emulsion film. And since I had several rolls of 36-exposure Kodak Tri-X in the fridge, I decided to use one. Working in my darkroom solely by feel, I pulled the entire roll of film out of the cassette, leaving the end attached. I then cut it in half, and loaded the cut portion into a second cassette, winding the film back into both, providing two rolls of about 15 exposures each (the “missing” six exposures now being used for leaders and trailers).

With the Tri-X loaded, I shot a number of images with the dual camera set-up once again.

The Second Results

So, did we find anything different with a traditional emulsion film? As before, note that in all images, Dilution B is on the left, Dilution H is on the right.

Forgive the parallax; for this shot, the two cameras were fairly close to the subject, and it’s quite apparent.

I took more photos, of course, but once again, the one image I chose is indicative of what I found more broadly across the roll, and as with Delta 100, there’s a slight increase in contrast with Dilution H.

Finally, let’s zoom-in and see if there’s any difference in grain in the uncorrected images.

This time, the results were a tiny bit different: I just couldn’t detect any appreciable difference in grain qualities.

So, with tests using Ilford Delta 100 and Kodak Tri-X 400 both completed, what’s the consensus?

The Answer

Before I give my answer, I want to set this context: It’s certainly possible that you may see things in these results that I do not, largely because some photographers are far more particular or exacting about things like negative densities and contrast than I happen to be; I tend to react to overall aesthetics more than technicalities, unless they’re particularly out-of-whack. In addition, there is a fairly wide latitude when scanning film negatives; I’ve gotten some good scans out of negatives that looked really lousy when hanging to dry, so perfection doesn’t strike me as particularly necessary goal. Even when I print my negatives to silver gelatin paper in my darkroom, my standards are somewhat less than perfection.

So, with that context out of the way, what’s my conclusion?

While some slight differences can be observed from completely uncorrected scans, typical scanning workflows will reveal no appreciable difference in the results between developing a film with HC-110 Dilution B, and developing the same film with Dilution H.

I’d be remiss if I didn’t point out that the results may also vary depending on many factors, including the specific film chosen, temperature control during development, darkroom processes and practices (e.g., agitation method and timing), and many other factors.

But for me, and with my own darkroom practices and techniques, my observations here will keep me doing things the way I have been: The choice of HC-110 dilution is a factor of how I want to spend my time (and how much of it), and not about any possible trade-off in the results I’ll achieve.

Footnotes

* Official film data sheets rarely provide development items for both Dilution B and Dilution H — if indeed they provide any HC-110 times at all. In most cases, if times are provided, it’s for Dilution B. The widely referenced Massive Dev Chart (MDC) is another source for the times, but you must bear in-mind that the MDC is community-sourced. As a result, you may be getting “official” times from data sheets, but far more often you’re getting values determined and contributed by photographers just like you, and may reflect darkroom technique and practices that vary from your own. For the record, I haven’t once (ever) experienced a situation where I got poor results from Dilution H after simply doubling the Dilution B times — and the times for B vs. H on MDC don’t seem to reflect my experience in that regard. In any event, when official times are not available from a film manufacturer’s own data sheet, and even if you use MDC suggested times, experimentation may be required to find the optimal times for your particular situation, and that match the results you personally prefer. Thankfully, since Dilution H is fairly weak, you’ll find there’s a pretty wide margin of error for most films.