The Online Darkroom Store

Monday, May 26

A quick guide to Spur developers

From some of the emails I've had since opening The Online Darkroom Store it seems some people are a bit confused about the properties of the developers I'm stocking. I'm not surprised as Spur produces a wide range of developers and their naming convention doesn't make life easy for photographers. HRX alone had about three earlier iterations before Heribert Schain came to the conclusion that it would not be possible to make the developer any better than it now is.

I chose the four developers carefully from Spur's range as I believe they cover all eventualities and meet all expectations photographers are likely to have. I've written a fair bit about the film developers but it's obviously spread around the blog and I think it would be a good idea to bring it all together in one place. Pending that, though, here's some more information that I hope will answer any questions readers might have about the products.


A lot of time and effort have been expended by Spur in perfecting this developer and it's all been worthwhile. I've been so impressed by Adox CHS 100 II negatives developed in HRX that I think I'll be making that combination my mainstay for 35mm work. Grain is lovely and fine and no less a figure than Leica guru Erwin Puts said in this review of HRX, Acurol-N and Rodinal that its resolving power is higher than that of Acurol-N and Rodinal - and he's forgotten more than I'll ever know about this sort of thing. Erwin concluded, "This is an excellent developer for Zone System users as it has a tonal range of 8 to 9 stops. Again an outstanding developer with indefinite keeping properties."

Adox CHS 100 II developed in HRX

However, it was the Adox/HRX ability to handle the extremes of highlight and shadow whilst still retaining well separated midtones that impressed me most of all. It's not too difficult to control highlights through reduced development, two-bath developers, compensating developers, etc, but all of these methods have a tendency to muddy the mids. HRX is as good a developer as you could wish for and it is certain to become my most used brew. I think CHS 100 II developed in HRX and Tri X developed in Acurol-N for my dull day work will be all I'll need from now on.

It's a two solution developer but is simplicity itself in use. You just work out how much neat developer you'll need in the same way you do for every developer and split that equally between solutions A and B. If, for example, you need 20ml to make up 500ml of working solution then it's 10ml of A and 10ml of B. The dilutions are all between 1+8 and 1+20 with the vast majority being 1+17 or 1+20. Development times are between 8 and 15 minutes - just long enough for consistency in processing but without the seemingly interminable times of the likes of dilute Perceptol.


This is the developer I've personally been using the longest from Spur's line-up and it really is excellent.  It's an acutance developer which means that it is designed to achieve "edge effects" by increasing the contrast along the boundaries of dark and light tones in the negative. Rodinal is the classic example of this but Acurol-N is an improvement as it manages to do this without over-emphasising the grain as Rodinal is wont to do. Erwin Puts said, "An outstanding developer with excellent keeping properties and also a very economical one."

In this review he concluded, "The Acurol-N developer is a major improvement for the darkroom workflow and should be a premium choice for anyone who is engaged in the silver-halide workflow, exclusively or in a mixed fashion, selecting the workflow that is best for the desired result." Below is one of Erwin's review pics which was taken on Ilford Delta 100. He says, "The high acutance can be seen in this shot (a selection of the full negative). Note also that the edges are very clean and do not show the familiar softening of the digital image because of color fringing."

The up-shot is that it produces negatives with high apparent sharpness. Compared to, say, D76, it is noticeably sharper but a little bit grainier. It has a punchy look about it that I think would be great for street and documentary photography or loaded in your favourite walkabout camera when you're on holiday and engaging in that most enjoyable of activities, being a "flaneur".

It's an economical developer, too, as it can be diluted at 1+100 for the likes of Ilford Pan F Plus. The standard dilution is 1+50 to 1+70. It has excellent keeping properties. Sealed in its original bottle, it will sit happily on your shelf for up to four years. Like Rodinal, it might turn brown in colour over time but this has no effect on the developing results. Water quality is important whenever developers are used at very high dilutions and Acurol-N needs soft, filtered, distilled or deionised water. Hard water requires much longer development times in Acurol-N and these would have to be worked out through trial and error by the user.


This is a sophisticated developer which produces a neutral print colour and excellent differentiation between greys. It's also good at retaining the subtleties of highlight tones whilst producing a well-defined black.

Around two minutes is a standard development time for Acurol-P. Spur make great claims of wonderful "plasticity" for this developer, especially at the recommended 1+15 dilution. I have to confess that I don't know what this means! I've been meaning to ask Heribert about plasticity but have yet to do so. Since I would just be guessing at a definition, I'll leave it up to some readers to put me out of my misery.


Not a developer but an additive that, depending on the dilution, adds a touch of warmth to prints. Old hands might remember the practice of adding some bromide to a print developer to warm up the blacks. Well, Acurol-W is a modern version of that approach.

You can add anywhere from 15ml to 40ml to a litre of Acurol-P depending on how much warmth you'd like. The shift in tone is dependent on the paper being used. I managed to get some additional warmth using it with Ilford MG IV RC, which isn't noted for it's abilities in this area, and a bit more with MG FB. With the latter, the difference between the neutral Acurol-P and with 30ml of additive is quite obvious (see below). With the likes of MG Warmtone and similar papers, the effect will be more marked.

Ilford MGIV FB Acurol-P with Acurol-W additive:
LtoR - +30ml, +15ml, no additive

Ilford MGIV RC Acurol-P with Acurol-W additive:
LtoR - +30ml, +15ml, no additive

Since adding Acurol-W reduces print density and contrast slightly, it must be used for the test strips/work prints as well as for the finished print. As a general rule, then, prints need a little extra exposure and maybe half to one contrast grade higher when using the additive. I decided to stock it because, along with Acurol-P, I would then be able to offer neutral and warm tone print developers.

Cool Black

This is the print developer for those who like cool-toned images and rounds out my selection of print developers. It's a very versatile developer that can also be used to subtly control print contrast through different working strengths. Dilutable from 1+9 to 1+19, it produces snappier prints at the stronger dilution and an extended tonal range at the weaker one. This isn't a massive difference but is a useful weapon to have in your armoury. 

Spur says there is a potentially fruitful area for experimentation in using two consecutive baths, one at 1+9 and the other at 1+19, for really subtle print tones. Some famous printers including Ansel Adams and John Sexton used/use the two-bath approach with Selectol Soft and Dektol in separate baths. A similar effect can be achieved using Cool Black at different dilutions.The recommended dilution for those of us who are less adventurous or enquiring is 1+11.

When used with most RC papers, the effect of Cool Black will be a neutral to very subtle cool look. I'll be taking a look at it with Ilford MG FB Cooltone in the near future to see how marked the tonal shift is with a more responsive paper. I've always liked the look of warm-toned prints but every time I see a nice cool tone print, I always come away surprised at how striking it is. Horse for courses, I suppose.


So that's the Spur line-up available at The Online Darkroom Store. I hope I've answered any questions you might have but, if not, then I'm more than happy to find out what you might need to know or ask Heribert if I can't help you directly. I'm at the stage where I'm very soon going to run out of Acurol-N but I'll be getting more in a couple of weeks. There are still decent amounts of the other developers available and HRX is the perfect substitute.


Elliot said...

Thanks for the informative and instructive post. I am tempted to try both Adox 100 II and Delta 100 in the developers that you have profiled.

Might I ask how you are printing the negatives that you have developed with the films and developers above? What paper(s), to what size, and what paper developer(s)?


Bruce Robbins said...

Very few prints lately I'm afraid Elliot. Mostly scans. The demands of a blog mean that regular material is needed and this is more easily produced by scanning rather than printing. Must make more of an effort to get back into the darkroom.

Anonymous said...

Careful, Bruce,you may get drawn back to the 'light side'! Here's a link to a couple of interviews with Andy Summers - who is featured on Ralph Gibson's website and another Leica Monochrom convert.

He, too, gives the nod to film; but it's a close call and the convenience outweighs any difference. Hope I haven't spoiled the read.


Bruce Robbins said...

There's no chance of me going back to digital, Mike. It just doesn't interest me now. Andy sounds like he's another film guy who's sold out to the convenience of pixels.

Anonymous said...

Convenience seems to be the reason, Bruce. Understandable if you are travelling and passing through many airports.