HC-110

HC-110 (also written HC110 in older Kodak literature, occasionally HC 110 in user posts) is Kodak's syrupy concentrated film developer — introduced in 1962 and continuously produced through Kodak's various corporate restructurings, including the 2019 reformulation that dropped HC-110's signature treacly viscosity in favor of a thinner liquid.^[1] It is the most operationally distinctive film developer in common use: a single bottle of concentrate keeps for years (genuinely — multi-decade-old half-empty bottles still produce usable negatives), and the same concentrate is used at multiple letter-coded dilutions (A through H+) for radically different development workflows from the same syrup.

HC-110 sits in the practical sweet spot for occasional B&W shooters: photographers who develop a roll every few weeks rather than daily. The concentrate's longevity means a $25 bottle of HC-110 can supply 200+ rolls over 5+ years, with no wasted oxidized stock — the developer that dilutes-on-demand. For mass-rolling labs working through a developer pot every week, HC-110 is more expensive per roll than D-76 or Microphen; the convenience is the value proposition, not the per-roll economics.

The various spellings — HC-110, HC110, HC 110, and the dilution-suffixed forms (HC-110 Dilution B, HC-110 Dil B, HC 110 dilution E) — all refer to the same product. Older Kodak datasheets used "HC-110"; community forums and modern repackaging often drop the hyphen ("HC110"); user search queries split across all variations.

When to choose HC-110 over D-76

HC-110 is most often weighed against D-76 (powder MQ workhorse), Rodinal (ultra-acutance liquid concentrate), and Diafine (two-bath alternative for occasional shooters):

• vs D-76 (powder): D-76 mixes from powder to a one-liter stock that must be used within ~6 months and replenished or one-shot diluted as it ages. HC-110 sits as concentrate and dilutes on demand — much more forgiving of irregular shooting schedules. Choose D-76 for predictable mass-rolling workflows; HC-110 for "I might develop a roll this month, or in 4 months."
• vs Rodinal (Adonal/R09/Studional): Rodinal is the other long-shelf-life liquid concentrate, but it's a high-acutance developer with pronounced grain and no solvent action — a totally different aesthetic from HC-110's smooth tonal-rendering. Choose Rodinal when sharpness + grain character matter; HC-110 when smooth tonality + push tolerance matter.
• vs Diafine: Diafine is a two-bath developer with extreme shelf life (years) and consistent times across films — even more forgiving than HC-110, but locked to specific dilutions and lacks HC-110's push range. Choose Diafine for the absolute simplest "one-time-fits-most-films" workflow; HC-110 when dilution flexibility matters.
• vs Microphen (PQ powder): Microphen delivers more effective speed (+⅓-⅔ stop) than HC-110 but requires regular use to amortize its 6-month stock life. Choose Microphen for routine push-processing; HC-110 when push is occasional.

The dilution-letter system — Kodak's signature operational design

HC-110's most distinctive feature is the multi-dilution letter system, encoding different concentrate-to-water ratios into single-letter shorthand. Original Kodak datasheets define:^[1]

Dilution	Ratio (concentrate:water)	Typical use case
A	1:15	Maximum activity; rare; high-contrast / push to EI 800-1600
B	1:31	Standard general-purpose; the most-used dilution; box-speed times in datasheets
C	1:19	Between A and B; some Tri-X workflows
D	1:39	Slightly more dilute than B; longer times for finer-grain rendering
E	1:47	More dilute; popular for compensating-development and high-contrast scenes; "dilution E" is a frequent search query for photographers learning the dilution range
F	1:79	Very dilute; semi-stand or stand-development workflows
G	1:119	Effectively stand development; 60-90 minute development times
H (1:63 — non-standard)	1:63	"Dilution H" is a community-coined dilution between F and G; popular for 35mm Tri-X for a Rodinal-like grain at HC-110 tonality

The standard reference dilution is B (1:31). Photographers exploring beyond B usually move to E (1:47) for compensating effect on high-contrast scenes, H (1:63) for fine-grain stand-development, or A (1:15) for aggressive push.

For accurate measurement of the syrupy concentrate, use a plastic syringe (5 ml or 10 ml) — the concentrate is too viscous to measure cleanly from a pour bottle. The 2019 thinner reformulation made measurement easier but lost some of the "single-bottle-for-decades" longevity character (still very long shelf life, just not "open the bottle from 1995 and develop a roll" levels).

Practical notes

• Concentrate shelf life: 2+ years sealed; 1+ years opened, even partially used. The 2019 reformulation dropped this somewhat (now ~1 year opened vs ~5 years for the original syrup) but it remains the longest-lived liquid developer in production.
• Mix dilutions one-shot: Once diluted, working solution should be used the same day and discarded. HC-110 working solution does not store well — the concentrate is the long-life form, not the working solution.
• Measure with a syringe: The pre-2019 syrup was nearly molasses-thick; the post-2019 liquid is thinner but still benefits from syringe measurement for accuracy at small volumes (5 ml in 155 ml water for one 35mm tank at Dilution B).
• Mixing temperature 20°C: HC-110 dilutes cleanly at room temperature; no need to pre-warm. Pour concentrate into water (not water into concentrate) to ensure full dispersion.
• Times shift after the 2019 reformulation: The new HC-110 is slightly more active than the old syrup — published tables from before 2019 may run slightly long. Reduce times by 5-10% as a starting point for the post-2019 product, or work from current Kodak times when available.
• PPE: Standard developer-handling — nitrile gloves and eye protection. The concentrate is alkaline; avoid skin contact especially during measurement. The diluted working solution is dilute enough that brief contact is harmless.

Related recipes

• [[recipe-d-76|D-76]] — Kodak's powder MQ workhorse; the comparison standard for routine workflows
• [[recipe-rodinal|Rodinal (Adonal/R09/Studional)]] — the other long-shelf-life liquid concentrate; high-acutance alternative
• [[recipe-diafine|Diafine]] — the simplest long-shelf-life two-bath alternative
• [[recipe-microphen|Microphen]] — PQ powder for routine push-processing workflows
• [[recipe-pyrocat-hd|Pyrocat-HD]] — staining-developer alternative when grain + acutance both matter
• [[recipe-xtol|XTOL]] — modern fine-grain alternative; powder; replenished workflow

Film-specific time tables

Times below are 20°C / 68°F starting points from current Kodak datasheets and Massive Dev Chart, cross-referenced for consistency. Adjust ±10% for your meter, water, agitation, and personal preference. All times assume continuous initial agitation (10 sec) followed by 10 sec every 30 sec.

Dilution B (1:31) — the standard reference

Film	EI / Box ISO	Time at 20°C	Notes
Kodak Tri-X 400	400	6:00	The canonical Tri-X + HC-110 combination; modest grain, full tonality
Kodak T-Max 400	400	8:00	Slightly longer than Tri-X due to thicker T-grain emulsion
Ilford HP5+	400	5:30	Faster than Tri-X in HC-110; reduce time 5-10% if HP5+ feels contrasty
Ilford Delta 400	400	7:30	Compensated for Delta's T-grain
Fuji Acros II 100	100	5:30	Fine grain; HC-110 preserves Acros's signature tonality
Ilford Pan F+ 50	50	5:00	Very fine grain at base ISO

Dilution H (1:63) — fine-grain stand-development

Dilution H is a community-coined dilution between F (1:79) and the historical Dilution G. Particularly favored for Tri-X in 35mm where the lower activity reveals finer grain than Dilution B.

Film	EI / Box ISO	Time at 20°C	Notes
Kodak Tri-X 400	400	12:00	The "Rodinal at HC-110 tonality" combination; classic 35mm fine-grain
Ilford HP5+	400	11:00	Similar effect to Tri-X but with HP5+'s slightly cooler tonality
Kodak T-Max 400	400	16:00	Long times typical of T-grain at high dilution
Ilford Delta 400	400	15:00	Compensating effect on highlights more pronounced at this dilution

Dilution E (1:47) — compensating effect

Dilution E sits between B and H. Useful when shooting high-contrast scenes (sun-and-shadow architecture, snow scenes) where you want the developer's compensating action to compress highlights.

Film	EI / Box ISO	Time at 20°C	Notes
Kodak Tri-X 400	400	9:00	Compensating; preserves shadow detail in contrasty light
Ilford HP5+	400	8:30	Similar use case; slightly less aggressive than Tri-X
Fuji Acros II 100	100	8:30	Acros + Dilution E preserves Acros's smooth highlight character

Push-processing matrix

Tri-X and HP5+ are the most-pushed films in HC-110 workflows. Push processing reduces shadow detail — push by stopping development time + agitation, not by reduced exposure. The shadow loss is real; this is a tradeoff for shutter-speed margin in low light.

Film	EI (push)	Dilution B time	Dilution A (1:15) time
Tri-X 400 → 800	800	8:30	6:30
Tri-X 400 → 1600	1600	12:00	9:00
HP5+ 400 → 800	800	7:30	5:30
HP5+ 400 → 1600	1600	10:30	8:00

Dilution A (1:15) is the standard push dilution — more concentrated developer increases shadow detail recovery while still giving the longer development time push processing requires.

Temperature compensation

If your tap water is colder or warmer than 20°C, adjust development time using the rule of thumb: ±10% per °C. For larger deviations, use the table:

Temperature	Multiplier on 20°C time
16°C	1.45× (longer)
18°C	1.20×
20°C	1.00× (reference)
22°C	0.85×
24°C	0.72×
26°C	0.60× (shorter)

For development times under 5 minutes, accuracy of temperature control becomes critical — 1°C drift can shift density visibly. Use a water bath or pre-warm/pre-cool the developer if your darkroom is far from 20°C.