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FX 4 Introduction

FX 4 was always a problem developer for me. I guess though, as I look back on it, I was really the problem.

I’m a curious darkroom worker, curious about how thing work, how are they made, and why things are the way they are. I guess it was this curiosity that got me interested in Geoffrey Crawley and his FX series. To me he thought things through differently to other photographic chemists and the more I read his work the more I agreed with his way of thinking.

Crawley was shaking things up a bit with the idea that 35mm shouldn't have to be a second class citizen anymore and that it was sharpness that created more impact and not that quality that so many photographers are attracted to, fine grain.

So, it was with this mindset that every so often I’d get curious and check out one of his developers. Crawley developers have bags of character and every one of them is different. Frankly, there’s not a bad one and actually there's some excellent ones that out-perform developers by even the likes of the behemoth in the photographic field, Kodak! It’s a shame that much of the world never really got to use Crawley’s formulations due mostly to poor distribution by Paterson and of course Kodak's massive marketing machine.

Many years ago I mixed some FX 4 and tested it on some of my favourite film - and to my shock I didn’t like it at all!

I should have known something was wrong but tossed the developer and moved on. I was young and impetuous (at least that’s my excuse now) and was probably comparing it to something like Acutol. But I should have known not all was at it seemed. I mean:

• It was slow! I was only getting box speed.
• It was a bit grainy! This was supposed to be fine grain but I didn’t experience that.
• It was too contrasty. It was supposed to give better tonality but I wasn’t impressed.

Well, if you haven’t guessed yet, all this was because I wasn’t using the developer properly - a lesson I’d learn much later on - that all developers need to be learned and not just used. It takes time, testing, and a few rolls of film. But, being young and far more impatient than I am now, I wrote the developer off and never went back to FX 4, at least until this series.

Now I find FX 4 isn’t that bad at all. Ok, it’s not his best Crawley solvent developer, that came sometime later, but for the 1960s, FX 4 was very good and very innovative.

So, with that background, let’s look a little deeper at this important developer.

Crawley’s first solvent developers

Whereas Crawley’s FX 3 was an improved Adox MQ Borax formula FX 4 was all new. This was Crawley’s first real attempt at improving on the speed-grain-acutance interlock with a solvent developer and to do this he used a technique that became his signature, the Crawley triple developer combination. His unique triple combination of the developing agents was metol with phenidone, supported by the super-additive hydroquinone. This was to become one of Crawley’s most important developer styles. As I think about it I remember he was mocked by other more traditional formulators and photographic technicians for these ideas, however, Crawley was really onto something that they simply didn’t understand and this three developing agent chemistry became a very effective method of formulation in some of the best of the FX range.

After the earlier FX developers, FX 4 was arguably Crawley’s most complex and carefully balanced developer in the range yet. It came with a much more controlled development action and was certainly an attempt at formulating a developer that:

• Improved pictorial impact through increased sharpness.
• Had fine grain, at least as fine as D-76.
• Maintained good film speed.

Sharpness and fine grain problems

Sharpness and fine grain don’t normally go together, as we see of course with D-76. I demonstrated in the FX 1 and FX 2 acutance developer chapters that ultimate sharpness means larger grain although, it has to be re-stated, this was largely mitigated by the higher definition of the final print thus tending to hide the grain from the viewers notice. FX 3 enhanced sharpness too but again, the grain was more noticeable than D-76 because of the reduced sulphite level. So, it seemed back in the 1950s that increasing sharpness will always increase grain. That, at least, was the view of many, if not all, photo-chemists. But Crawley looked at the problem through a different lens and figured out a way to achieve this paradox using a new and novel technique. He believed that he could keep the solvent level higher, thus keeping the grain at a similar size to D-76, but use three developing agents. I think he used one to enhance sharpness, one to enhance film speed, and one to keep them going.

It’s well known that phenidone can enhance film speed but is not believed to be as sharp as metol. The reason is that phenidone is better at reducing halide crystals that have had less exposure to light (the toe) but doesn’t react as much as metol to development by-products. With sharp acutance developers such as FX 1 it’s the by-products, bromide and iodide, that cause the metol to enhance the feeling of sharpness around high contrast boundaries, explained in detail in the FX 1 chapter earlier. Phenidone just isn’t affected as much by these bromide by-products. So Crawley added both phenidone and metol together. He was onto something here but to maximise the advantage of using these two developing agents together he needed to hit the sweet spot of amounts of each, the overall alkalinity, the amount of solvent, and the delicate amount of restrainer (such as potassium bromide). With FX 4 he didn’t quite hit that sweet spot but a few years later he certainly would with FX 15!

The hydroquinone could be doing more than regeneration

I might add the hydroquinone is the third developing agent but here it just regenerates both phenidone and metol; so they don’t oxidise and fail. The borax alkalinity is too low for the hydroquinone to do any of the actual halide reduction. However, the hydroquinone might be assisting in sharpness! You’ll note that the amount of hydroquinone is less than FX 3 and is being shared between both developing agents in FX 4. Could this be helping with sharpness? Could the metol be creating acutance at contrast boundaries because it’s being a little starved of regeneration? I don’t know but it’s worth thinking about, especially as Crawley’s later fine grained acutance developers had even less hydroquinone. I believe this might well have been another of Crawley’s strategies with his solvent developers, finely balancing the hydroquinone to fine tune regeneration and enhance acutance.

Amount of hydroquinone in Crawley's solvent developers

Some Crawley Solvent developers	Hydroquinone levels per litre working*	Other developing agents
FX 3	6g	Phenidone
FX 4	5g	Metol, Phenidone
FX 15 Acutol-S	2.25g	Metol, Phenidone
FX 24 Aculux**	1g	Metol, Phenidone

• Full strength working solution ** Uses Potassium thiocyanate as solvent

It should be stated that the alkalinity of FX 15 and FX 24 is higher than FX 3 and 4 and so hydroquinone’s development ability might be activated a little more. However, being at such a reduced amount the hydroquinone will probably also starve the metol and phenidone of regeneration and this will enhance acutance. FX 15, in particular, has improved acutance compared to FX 4.

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Note:
D-23 doesn’t use hydroquinone to regenerate the metol but there’s a lot of metol available for reduction of halides. It’s also softer on the highlights because of the metol reacting to bromide by-products from the film.

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Compensating highlights and fine grain

FX 4 has a slight compensating effect that Crawley talked about, useful of course for controlling bright areas such as skies. Can we have a developer that gives fine grain and compensation?

Many developers provide highlight compensation. This is usually achieved through dilution. By increasing dilution one lowers the amount of developing agent available to reduce the silver halides. Therefore, where a lot of developing action is going on, such as in those highlights, the developer slows, developing less, until replaced by agitation. This is how semi-stand or stand development works to reduce contrast and compensate highlights.

Another method, used for compensation, is two bath development. This too uses developer exhaustion in bath B to slow down development in the highlights while keeping it going in the, less exhausted, shadows.

But there’s an unfortunate side effect, specifically with solvent developers. Increasing dilution reduces the fine grain because the solvent concentration (usually sulphite) is now lowered well under an adequate level for silver grain etching and re-plating (the basis of the fine grain effect). This same problem happens both with dilute developers and with two baths.

Let’s look at an example, the solvent developer D-76. At full strength there’s 100g per litre sodium sulphite, a good level for etching and re-plating and the subsequent fine grain. At 1+1 dilution there’s 50g per litre, just above the 45g per litre minimum solvent level that begins the fine grain effect (according to Crawley). Unfortunately, at the 1+1 dilution, there’s little compensation so to get more we are forced to dilute further, to 1+2 or 1+3. By now, at 1+3, our solvent level is a meagre 25g per litre, much too low to maintain the fine grain status of the developer. At this sulphite level, and with such dilute developing agents, D-76 has actually started to become a sort of acutance developer (not, I might add, a well balanced or particularly good one).

We’ve managed to obtain compensation with D-76 but at the cost of fine grain.

Crawley’s FX 4 probably compensates highlights a completely different way and I suspect it’s because of the metol. Without the metol being fully regenerated, and because of the build up of by-products in the high development areas like the sky, I think the metol is running out of steam. This then leaves only the phenidone and basically retards development and provides compensation. By the time the phenidone has developed the shadows and mid-tones the metol has been slow in the highlights so by personal development time completion there’s some pleasant compensation.

Of course, I don’t know what Crawley was thinking or doing but these theories around his formulations seem quite logical. His pursuing of the three developer combination, metol, phenidone, and hydroquinone, certainly gave his developers some qualities that others just didn’t have. They surpassed the best that the giants like Kodak could produce. Yes, there was some complexity in it but to Crawley it was worth it and for me knowing that his developers were some of the most researched, modern, and most successful in photographic application I’m glad he followed this research in formulation.

FX 4 Formula

FX 4 formula

Chemical	Amount
Water 50C	800ml
Metol	1.5g
Sodium sulphite Anhy.	100g
Hydroquinone	5g
Phenidone	0.25g
Borax	2.5g
Potassium bromide	0.5g
Water to make	1 Ltr

• The amount of phenidone is the same as FX 3 yet Crawley added 1.5g of metol and reduced hydroquinone a little.
• I recommend 1+1 as the best balance for sharpness and grain for cubic grain films (such as FP4)
• 1+3 recommended for tabular films.

I am providing the most common formula here and the one I tested. At least one time the formula was written with an increase of hydroquinone by a gram, to 6 grams. However, it seems that this formula is the most used and published and the other might have been just a misprint.

Like FX 3 I found the development time was quite quick, just 7 minutes at a 1+1 dilution using 30 seconds of constant agitation followed by 2 inversions every minute. Unlike FX 3s ISO boost I found the film speed to be box at best. In the past I have used this developer more like D-76 and halved the film speed and it works well like that. The tests I did here were at EI125 but shadow detail is wanting even though my film speed test showed that was the speed given. This is a quirk of this developer.

Tonality

The developer tonality is good. Above is a comparison of FX 3 and FX 4.

This comparison, a 100% scan enlargement, demonstrates the similarities of FX 3 and FX 4 in tonality. It also demonstrates some of the compensation with FX 4. Looking between the chimneys one can see that the FX 4 has slightly more micro-contrast and sharpness. To the right of the chimneys the FX 4 has compensated a little. Tonality wise, the FX 4 has better tonality to me, the chimneys looking rounder because of the more subtle gradation. However, these differences are small in 120 film and in a 12 inch square print, held at 10 inches, it’s not really apparent.

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Tip

Minimum advised viewing distance for a 12 inch square print is around 30 inches (76cm). At this distance I see no discernible difference between FX 3 and FX 4.

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Sharpness

FX 4 is a reasonable sharp solvent developer but not an acutance developer. It is a little sharper than FX 3 in FP4 120 film (below) but again, at normal viewing distances any difference would not be visible.

Note: Due to the slower film speed given the FX 4 enlargement below needed a little more gain in the scanner. This accounts for the speckles and lighter shadow areas.

Grain and sharpness comparison with FX 2

The below comparison shows the fine grain of FX 4 compared to FX 2 the glycin acutance developer. It also demonstrates the difference in sharpness! FX 2 has a lot more micro-detail and a clear Mackie line along the top of the gate. This only barely shows on the FX 4 negatives.

Although the FX 4 is sharp it’s nowhere near as sharp as FX 2. But at this stage of Crawley’s developer formulations he was still experimenting with obtaining acutance with solvent developers. It would not be until FX 15 that he really obtained it.

Film speed and pushing

I measured the film speed for FP4 with FX 4 as 125 EI, 1/3 stop better than D-76 and less than Crawley's claim. But having used this developer before I think it likes a little more exposure than that, at least to get the best results for landscapes. If you try it I suggest over-exposing by halving box speed on the meter and reducing development to 6 minutes at 1+1 dilution.

Because of this I don’t think this would be a good candidate for pushing film. I have never tried it, so I could be wrong, but I feel more active developers are better for under exposure and over development, such as FX 3, FX 11, and FX 55.

Capacity

This developer has very good capacity when used as stock processing no less than 10-12 films per litre. Just add 5% to development time for every film after the first.

Conclusion

I’m very aware that I didn’t like FX 4 when I first tried it many years ago. This is unfortunate because it’s not a bad developer actually. But it just feels like it’s not Crawley’s best when I use it. Having tested it thoroughly (and just after FX 3), using some of the same shots from the lighthouse that I took that day, it didn’t really bring any more to my prints than FX 3. In some ways I actually preferred FX 3 for its brighter glowing highlights, its punchier contrast. It’s this punchier contrast that FX 4 actually compensates out a little, perhaps! It’ll be interesting to compare FX 4 to FX 15 and 18 but that’s further down the line.