2-Bath Pyrocat-HD, the “Magic Brew” Part I

This is a hardcore film user post, read at your own risksThis post is about a “Magic Brew,” with the major benefit of this process being that you can develop a roll of film with different contrast for the images and get good base negatives usable for scanning and digital post processing.

First, lets look at this excerpt:

4. For development in Jobo with constant rotation I would recommend the following protocol.

 a. Use a 1:15 or 1:20 dilution of Pyrocat Stock A and Stock B for most films.
    Add a few [drops] of PhotoFlo to the solution [A].
 b. Pre-soak the film for two or three minutes in water at 75º F.
 c. Develop for five minutes in working Solution A, at 75º F. Then drain the film for 15 seconds.
 d. Develop for five minutes in working Solution B, at 75º F.
 e. Use a 1/2 strength acetic acid stop bath for 10 seconds.
 f. Fix in any standard fixer. I use an alkaline fixer (TF-3) but the use of a slightly acidic fixer is ok.
 f. Wash the film for 10-15 minutes, drain and dry.

OK, so it’s still the standard develop, stop, and fix regiment, except that apparently there are two developers, no big deal… Wait, what film is he talking about?

First of all, “he” is Sandy King, a long time photographer and inventor of the Pyrocat-HD formulation, and the film that he is talking about? “most film,” as he says – meaning that just about any traditional B&W film. If you have done B&W developing, you know that the length of development normally differs for different films, depending on the Contrast Index (CI) you want (which is of course influenced by the developer, the film, and the developer temperature).

The difference here is that with a 2-bath process, no development is happening in solution A, it is just a “reducer,” waiting for solution B to be incorporated where development actually occurs. Development happens almost instantaneously when solution B is poured in – most development happens in the first 30 seconds, but the continual soaking would develop the shadow details more.

According to King, the emulsion will be mostly saturated after about 5 minutes or so at 75 degrees and further soaking would not effect too much additional change. If the final contrast is too low, then you can try increasing the temperature or lessen the dilution ratio.

2-bath developers are not new, but using it with modern films is somewhat new, and using it for the explicit benefit for scanning and digital post processing is a recent discovery by King. This process works so well because it holds the highlight and yet allows the shadow areas to develop fully, compensating for any high contrasty scene so that more information is captured on the negative. It can give a very flat looking negative and may not be great for darkroom printing, but it is exactly what you need for digital darkroom.

Most people who use this process so far are large format film and medium format roll film users. Normally, they would carefully note the dynamic range of the scene (the “zone system”) and develop each sheet of film accordingly. On the other hand, this approach gives a good base negatives for scanning and digital processing, regardless of the zonal range of the original scenes: a less fussy way upfront because you want to do the magic in post processing anyway. A tailored individual development of each sheet of film is probably still the best, but skillful digital processing is a master leveler. Moreover, it is impossible to develop each frame individually for medium format and 35mm roll films.

In my mind, this process is a bit similar to using the raw format in a digital camera, which is also usually flat for the same reasons – more of the data is there to begin with. Starting with this flat image, you can further “develop” the raw image into something more exciting using the digital darkroom tools.

Note that your images must still be exposed correctly. This is a magic brew, but not THAT magical

The 2-bath developer I am using is Sandy King’s invention – the Pyrocat-HD. If you try this, I recommend getting the liquid premixed solutions, rather than mixing your own from powder as that can be more toxic. Otherwise, normal darkroom handling procedures apply (i.e. avoid contact, rinse off carefully and don’t drink the stuff). Pyro developers are known for their staining properties. According the Barry Thornton (from “Elements of Transition”):

A really good approach for scanned negatives is to use a tanning / staining developer [...] Not only do these give the super acutance edges and detail we want without excessive grain, they also mask that grain. As the film develops in these solutions, complex compounds are released from the silver grains suspended in the gelatine layer that forms the film emulsion. These compounds tan the gelatine and close its pores to the ingress of further developer in direct proportions to the developer activity, which is highest in the areas of the negative which have had the greatest exposure. Thus over-development of the highest densities is automatically restrained. These tanning compounds have another vital attribute. They stain the gelatine between the clumps of silver grains.

[...]at least partially, hid the grain clumps. Use a staining developer for negatives that are to be scanned if you want a smoother scan…

Wow, doesn’t this make the 2-bath Pyrocat-HD sound just perfect for developing 35mm and 120 roll film for scanning? Now you can see why I was so excited.

Enough talk, how does it work? I only had time to test it on two rolls with the Hasselblad XPan: Fuji Acros 100 and Kodak Tri-X – a fine grain modern film and the standby film with ancestry dated back in the 1950s. Unlike before, I rated the Tri-X at ISO400 as Pyrocat is more active than non-Pyro developers. For the Acros, I used 1:20 dilution. For the Tri-X, I used 1:24 dilution, which I think I will standardize on. To clean off any photo-flo residue, I soak the tank and reels in hot water bath for 10-15 minutes afterward,

Here are some photos, only the last one of the Stanford New Guinea Sculpture Garden is from the Tri X, as I have not have time to scan more images in yet, but I do love the tonalities I am seeing. Very sharp images too.