HC-110 Developer

I today purchased some HC-110 developer from a local store and will get it soon. It will compliment my main developer which is Xtol. The reason I got HC-110, was it works really well with older films that might have some base fog on them. Im told it keeps fog down a bit when developed. Plus this developer keeps for a long time on the shelf. I have a large stock of old film in my freezer. It would help some of them for me, especially the 400 speed ones.

I read Kodaks PDF file on the instructions, but Im confused about one thing. When mixing this all up, it lists 2 lists of amounts to mix up a solution. One is "stock solution" and the other is "working solution from concentrate". The stock solution says for 300ml, to mix up 38ml of stock solution to 262 ml of water for dilution B. For concentrate, it says 9ml of concentrate to 291 ml of water for dilution B. Which technically do I use if getting it straight out of the bottle? If its concentrate, what do they mean by "stock solution" then?

Another thing I'll ask- when using this developer to keep base fog down on the film, should I develop for normal times, or would you modify that somewhat to help fog? What dilution is recommended for this?

braxus said:

I today purchased some HC-110 developer from a local store and will get it soon. It will compliment my main developer which is Xtol. The reason I got HC-110, was it works really well with older films that might have some base fog on them. Im told it keeps fog down a bit when developed. Plus this developer keeps for a long time on the shelf. I have a large stock of old film in my freezer. It would help some of them for me, especially the 400 speed ones.

I read Kodaks PDF file on the instructions, but Im confused about one thing. When mixing this all up, it lists 2 lists of amounts to mix up a solution. One is "stock solution" and the other is "working solution from concentrate". The stock solution says for 300ml, to mix up 38ml of stock solution to 262 ml of water for dilution B. For concentrate, it says 9ml of concentrate to 291 ml of water for dilution B. Which technically do I use if getting it straight out of the bottle? If its concentrate, what do they mean by "stock solution" then?

Another thing I'll ask- when using this developer to keep base fog down on the film, should I develop for normal times, or would you modify that somewhat to help fog? What dilution is recommended for this?

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For dilutions the best information is probably at http://www.covingtoninnovations.com/hc110/.

That webpage also contains a lot of other good information about hc110.

Also, a lot of people skip the stock solution and dilute directly from the concentrate.

There are two ways to work with HC-110.
Originally, it was designed for use by large volume commercial labs. They would use up an entire 16 ounce bottle in a short time. They would mix up a half gallon of stock solution by mixing one entire 16 ounce bottle into enough water to make 64 ounces of stock (that is an initial 1 + 3 dilution).
The lab then used that stock solution in a number of different ways - mix stock 1 + 7 (resulting in dilution B) for a deep tank that emulated something like D-76, or 1 +3 (resulting in dilution A) for a deep tank that emulated a different developer used for lith film, etc.
The commercial labs would use up that half gallon of stock solution quickly, so it made sense to make the subsequent dilution into a variety of different working solution developers simpler and quicker by first diluting it into an easier to handle stock solution.
For them, the first set of dilution from (previously mixed up) stock dilution instructions apply.
Most of us though prefer to use small quantities of HC-110 concentrate one roll (or maybe 2-4 rolls) at a time, and by doing so extending the life of the concentrate. So for us, the second set of dilution from (directly from the bottle) concentrate dilution instructions apply.
By the way, if you have a bunch of rolls of film to develop in a short time, it is quite convenient to make up the right amount of 1 + 3 stock first, and then further dilute that stock immediately before using it.
Also by the way, the new HC-110 concentrate will probably last reasonably well, but is unlikely to last for the extraordinarily long periods that the previous version lasted for.

Normally, I only develop one or two rolls at a time. I divided the bottle between four 250 ml dark glass bottles and went to the local drugstore for cap plugs and a syringe. The plugs fit firmly in the bottle and I can draw up the exact amount of concentrate for mixing. It keeps the developer fresher and I’m not wasting any.

going straight from the bottle, use the "from concentrate" instructions.

That covington web page is a good reference.

The original formulation of HC-110 was a thick syrup and small quantities were hard to measure accurately. Syrup would stick to the side of a graduated cylinder or it took lots of agitation to dilute completely. So Kodak instructed to dilute the entire bottle of "concentrate" with (something like) three times that much water to make a "stock solution". Which would some time later be again dilluted to make a "working solution".

The current formulations is runnier and easier to measure the 5, maybe 10ml that you use for a roll of film "directly from concentrate".

Thanks guys. I guess its the concentrate mix I'll be using. I wont be using this developer nearly as much as Xtol, so it will have to keep in its original bottle for a while.

Syringe plugs fit the big bottle, too!

I have used HC110 for HP5 film 5-8 years past expiry date (kept at room temp) some exposed when they were still fresh, all with my standard recipe and all with perfectly printable results - to such an extend that I don't bother to freeze or refrigerate my film stock anymore if I expect to use it within a few years of the expiry date.

My standard dilution is 16ml+1000ml - that is approximately dilution H - it is not on the bottle, but provides good economy yet reasonable development times (8 min@ 24C in this case).
I also recently found HC110 that was 7 years past its expiry date, kept in a quarter filled bottle, rather brownish in color, but it worked without issues with my standard dilution.

The new HC110 with a lighter viscosity can be used exactly like the old formular, but it is too early to say if it will last as long - that is only speculations at this point.

braxus said:

I today purchased some HC-110 developer from a local store and will get it soon. It will compliment my main developer which is Xtol. The reason I got HC-110, was it works really well with older films that might have some base fog on them. Im told it keeps fog down a bit when developed. Plus this developer keeps for a long time on the shelf. I have a large stock of old film in my freezer. It would help some of them for me, especially the 400 speed ones.

I read Kodaks PDF file on the instructions, but Im confused about one thing. When mixing this all up, it lists 2 lists of amounts to mix up a solution. One is "stock solution" and the other is "working solution from concentrate". The stock solution says for 300ml, to mix up 38ml of stock solution to 262 ml of water for dilution B. For concentrate, it says 9ml of concentrate to 291 ml of water for dilution B. Which technically do I use if getting it straight out of the bottle? If its concentrate, what do they mean by "stock solution" then?

Another thing I'll ask- when using this developer to keep base fog down on the film, should I develop for normal times, or would you modify that somewhat to help fog? What dilution is recommended for this?

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Sometimes the anti-fog action of the old version is attributed to PVP and it is not clear if this is still present in the new version.

Alan Johnson said:

Sometimes the anti-fog action of the old version is attributed to PVP and it is not clear if this is still present in the new version.

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I really hope it does. Its the reason I bought some of this. I got my bottle yesterday. Would there be any info on the bottle indicating if it has PVP? Does anyone know the answer to the new mix of HC-110?

There is a new MSDS which makes it clear that it has been modified.
But as an MSDS is not required to list all components, you can't tell whether a particular component is there. Only the potentially hazardous stuff will be listed in the MSDS or on the bottle.
The formula - new and old - is proprietary, so no one outside of the people who have and had responsibility for its makeup could tell you.
Under normal use, it seems to give the same results as the old stuff. Whether it has the same anti-fog characteristics will likely only be determined through relatively extensive experiments.
The changes to the MSDS at least hint at it having a more normal life than the old version - no half empty bottles still working fine after many years - but the jury is still out on that issue - at least partially because it hasn't been around long enough to answer the question.

Silvergrain article on HC110 | Photrio.com Photography Forums
PE said he knew of several more compounds used to prevent fog.

Ian Grant said:

For easier comparison:

HC110 Old


Chemical name CAS No. Weight/Percentage

Diethanolamine 111-42-2 30 - 35

Sulphur dioxide 7446-09-5 15 - 20

Hydroquinone 123-31-9 5 -10

Diethylene glycol 111-46-6 5 -10

Ethanolamine 141-43-5 5 -10

Diethylenetriaminepentaacetic acid 67-43-6 1 -5

Potassium bromide 7758-02-3 1 -< 5

1,2-Benzenediol 120-80-9 0.1 -< 1

Ethylene glycol 107-21-1 0.1 -< 1

3-Pyrazolidinone, 4-methyl-1-phenyl- 2654-57-1 0.1 -< 1



HC-110 New

Chemical name CAS No Weight/Percentage

Hydroquinone 123-31-9 10 - < 20

Potassium sulphite 10117-38-1 10 - < 5

Diethylene glycol 20111-46-6 5 - < 10

Sodium tetraborate, pentahydrate 12179-04-3 1 - < 3

4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidinone 13047-13-7 0.1 - 1

Diethanolamine 111-42-2 0.1 – 1

Potassium hydroxide 1310-58-3 0.1 – 1

1.2-Benzenediol 120-80-9 0.1 – 1

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Saw this in the other thread. Is this accurate or has it changed from this since?

Different jurisdictions have different requirements for what needs to be included in an MSDS, and no MSDS includes every ingredient, so basing conclusions on MSDS is at best, unreliable.