Kodak Tri-X 400 in Ilfotec DD-X 1+9

  2016 June 23    Film   Developing


Ilfotec DD-X is a speed-enhancing developer for black & white film.  DD-X provides good tonality and (usually) reasonably fine grain.

This is a page of notes and dev times for DD-X at 1+9 dilution.  (See also How to Develop B&W Film.)

A Quick Note

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How Much Per Roll?

Temperature & Dev Times



If you want to dilute DD-X, the most often-used choices are 1+4 or 1+9.  That means the dilution factor will be either 1/5 or 1/10.  The 1/10 dilution factor (i.e., the 1+9) is more economical.  It also lets you use longer dev times that reduce the percentage error.  That means if you make, say, a 30-second error, it won't be as big a problem.

To make 1+9 DD-X, mix 1 volume of DD-X with 9 volumes of water.  So, if you wanted to make 350 ml of 1+9, you would mix 35 ml of DD-X with 315 ml of water.

If you wanted to make a liter of 1+9, you would mix 100 ml of DD-X with 900 ml of water. 

Kodak Tri-X 400 in Ilfotec DD-X 1+9

This picture was for the Clamping Blocks article (Woodshop tips).

How Much Per Roll?

A roll of 135-36 film requires about 12.5 ml of undiluted DD-X.  That's not enough to submerge the whole roll;  it's just the minimum amount that will convert the silver halides.

At 1+4 dilution, you would need 62.5 ml of solution to develop one roll.  Again, this is not enough to submerge a whole roll in a Paterson tank;  it takes about 350 ml of liquid to do that.

1+9 is only half as concentrated as 1+4, so you would need 125 ml per roll.  Using 350 ml to cover a full roll with liquid, that would be enough for almost 3 rolls.  But you would have to calculate depletion for the 2nd and 3rd rolls.  See how I did this with HC-110

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Temperature & Dev Times

FilmKodak Tri-X 400
E.I.  400
Developer & Strength:  DD-X at 1+9 dilution

minutes:seconds at various temperatures:

17:43 at 65 F
16:45 at 66 F
15:51 at 67 F
15:00 at 68 F
14:10 at 69 F
13:24 at 70 F
12:41 at 71 F
12:00 at 72 F
11:21 at 73 F
10:44 at 74 F
10:15 at 75 F
9:37 at 76 F

Someone remind me to make a table of these values and include Celsius.  (I rarely use Celsius for film developing, but you guys everywhere else in the world probably don't use Fahrenheit all that much, either....)

Agitation:  continuous for the first 30 seconds, then 10 seconds every 2 minutes.  With the Paterson tank, four complete back-and-forth swirls take about ten seconds.

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Ilfotec DD-X works great at 1+9  (i.e., 1:10 dilution).  At this dilution, it makes DD-X a contender with other developers that otherwise cost less.

Not only that, but it also gives nice tonality and relatively fine grain.  I like DD-X 1+9 almost as much as HC-110 Dilution B.

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