ISO 400 35mm, developed in HC-110B

    Film   Developing


HC-110 is an extremely versatile developer for black & white film.  It yields fine grain, it works well at high dilutions, and it can push film to extreme levels.  One big advantage is that it doesn't elevate base fog as drastically as some other developers. 

Most of the time I use Dilution B, which consists of one part HC-110 concentrate (USA version) plus 31 parts water, by volume.  (See also How to Develop B&W Film.)

Here are some mixing instructions, temperature notes, etc.

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In This Article



How Much Per Roll?


Correcting for Depletion



Dilution B is "1+31", which means for every 1 ml of concentrate, you would use 31 ml of water.  In chemistry this would be called a 1:32 dilution, although some of you guys will call that a 1:31 dilution.  This seems like a molarity vs. molality type of situation, where some of you guys are using "solute:solvent" rather than the customary "solute:solution".  The latter is what we need for geometric progressions when making a series of dilutions.  But you might have worked somewhere that didn't require that.

So anyway, diluting HC-110.

The concentrate has a high viscosity, and it's rather slow to dissolve.  If you want to make a liter, first add exactly 31 ml of HC-110 concentrate to a 100-ml graduated cylinder.  While swirling it carefully, add enough water to make 100 ml.  It does not have to be exact at this stage.

When you've dissolved as much of the HC-110 as possible, pour that solution into a 1000 ml graduated cylinder.  Then add more water to the 100 ml cylinder to dissolve the leftover HC-110 that didn't dissolve.  Now pour that into the 1000 ml cylinder.  Repeat once or twice more.

By now you should have three or four-hundred ml of solution in the 1000 ml cylinder.  And there should be no HC-110 left in the 100 ml cylinder.

Finally, add just enough water to the 1000 ml cylinder to bring the total volume up to 1000 ml exactly.

Get some HC-110 here

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Store the solution in an airtight container with as little air space as possible.  Store all your developing chems in a secure location.  Keep the HC-110 away from heat, because that will use up the developing power more quickly. 

I highly, highly recommend that you invest in a couple of 1 qt. photo chem containers for your developer solutions.  Wrap the cap with several turns of electrical tape to discourage casual curiosity.  (It could also help to slow oxidation.)  Developing chems in general are not any more toxic than a number of other household chemicals.  That said, treat them with the same respect as bleach, detergent, antifreeze, ammonia, etc. 

Get some HC-110 here

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How Much Per Roll?

A roll of 135-36 film requires about 6 ml of undiluted HC-110.  That's not enough to submerge the whole roll;  it's just the minimum amount that will convert the silver halides.

At 1+31 dilution, the volume of liquid required is going to be 32 times 6 ml.  So, it would take 192 ml to develop a roll.  But that's still not enough to immerse a whole roll at once.

Using 350 ml to cover a full roll with liquid, that would be enough for not quite 2 rolls.  This is why I usually just mix up one liter, then calculate for depletion.  See how to do this

Get some HC-110 here

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Temperature and Dev Times

FilmKodak Tri-X 400 or almost any 400-speed black & white film. 
E.I.  400
Developer & Strength:  Kodak HC-110 at 1+31 (i.e., "Dilution B").

minutes:seconds at various temperatures:
7:05 at 65 F
6:42 at 66 F
6:20 at 67 F
6:00 at 68 F   
5:40 at 69 F
5:22 at 70 F
5:04 at 71 F
4:48 at 72 F
4:32 at 73 F
4:17 at 74 F
4:04 at 75 F
3:50 at 76 F

An extra 20 to 30 seconds in a 6-minute dev is not going to wreck your film, and it might actually be good for it (some people use 6:30 instead of 6:00 for a roll of Tri-X.  When you start getting into sub-4-minute dev times, it will make more of a difference.  If you have to develop at temperatures above 72 F, you might want to use "unofficial Dilution H", which is 1+63.  Then you would double the dev times shown above.

Agitation:  continuous for the first 30 seconds, then 10 seconds every minute.  With the Paterson tank, four complete back-and-forth swirls take about ten seconds.

Get some HC-110 here

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Correcting for Depletion

If you mix up a liter of HC-110 dilution B, you'll have to use correction factors because of the depletion for each roll.  To learn how and why I worked these out, see this article.

Don't forget to convert minutes:seconds to a decimal, then back to minutes:seconds after you multiply!!

First roll of 135-36.....develop normally

Second roll of 135-36.....multiply the normal dev time by 1.25

Third roll of 135-36......multiply the normal dev time by 1.67

Fourth roll of 135-36......multiply the normal dev time by 2.5

Fifth roll of 135-36.....multiply the normal dev time by 5 and use a larger develop tank that will hold the entire liter. 

Get some HC-110 here

Table of Contents


Kodak HC-110 is brilliant.  It may be one of the most broadly-useful film developers ever invented.  It's also economical, because the concentrate makes a lot of developer solution.

If you do everything right, Dilution B for six minutes at 68 Fahrenheit should yield good results with almost any 400-speed black & white film.  I even develop T-Max in this stuff.

There are differences, because not every 400 film is going to behave just like Tri-X.  But it's a good starting point, and it works great for Ilford HP5+ 400 also.

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