How Far the Recipe Travels: Silver Mirroring Beyond RC
Part 3 of 4 in the Silver Mirror Toning series | ← Previous: Part 2 | Next: Part 4 →
Lexy Xiao developed her silver mirroring recipe mostly on black and white sheet film and resin-coated paper — Ilford Pearl, largely. That is a sensible place to develop anything. RC is cheap, fast, dimensionally stable, and forgiving of the kind of repetition you need when you are working out a process from scratch rather than following one.
It is also not what I print on. My practice runs mostly to fibre, to lith, and increasingly to colour, and so I left the workshop at Mörk with a fairly narrow question: would the recipe work on my papers?
What follows is a working document rather than a set of conclusions — several substrates, one recipe, and two results interesting enough that I still cannot fully account for them. The chemistry and the two sequences are in 034; I will not restate them here.
Fibre: FomaBrom 111
The obvious first test, and the least dramatic to write about, which is exactly why it matters.
I had half expected fibre to behave differently. A fibre print has a thicker emulsion sitting on a baryta layer sitting on paper that actively absorbs the bath, where an RC print has a thin emulsion between two plastic layers that absorb nothing. If the mirroring depends on what the emulsion can hold and how quickly the bath clears out of it, those are not obviously equivalent situations.
In practice, both directions worked, and worked well. Direct toning gave clean mirrored highlights against normal blacks. Indirect gave the inversion — shadows that go bright and metallic at a glancing angle while the highlights stay paper white.
The one adjustment fibre needed was time. Where RC mirrors quickly, 111 wanted a few minutes in the bath, which is roughly what you would expect from a thicker emulsion on an absorbent base — more material for the chemistry to work through, and more of the bath disappearing into the paper instead of staying where it is useful.
What does differ is the surface underneath. On RC the mirroring sits on a manufactured, uniform plastic sheen and reads as a coating. On fibre it sits on baryta, and reads more like something the paper is doing than something applied to it. That is an aesthetic judgement rather than a measurement, and you may well disagree, but it is why most of what I have made since has been on 111.
Lith: Two Papers, Two Answers
This is the most interesting failure in the set, and the one I would like to understand a bit better.
Lith prints are an obvious target for indirect toning specifically. Direct toning would compete with the print's own highlights, but indirect works on the shadows and leaves the highlights largely alone — and the highlights are where a lith print keeps its colour. In principle you get metallic shadows with all the warmth and grain of the lith intact above them. In principle.
On Retrobrom 152, that is precisely what happened. Shiny in the shadows, and the lith colour stays. I would not claim it as the best print of the project, but the two effects genuinely coexist rather than one flattening the other, which was the open question going in.
On FomaTone 132, nothing. Not a weak effect, not an uneven one. No visible change at all.
Same bath, same temperature, same session, same sequence. I have four candidate explanations and no way to choose between them yet:
- Grain morphology. Lith's infectious development produces large, irregular, heavily aggregated silver particles rather than the fine even grain of normal development (see 030 for why). Perhaps the copper chloride bleach simply does not rehalogenate that structure as readily, and on the 132 print there was nothing for the toner to work with.
- Emulsion chemistry. FomaTone is a warm-tone paper with a different halide balance. Halide composition affects both bleach behaviour and how readily silver re-precipitates.
- Density. The 132 print may have been denser than the bleach could penetrate in the time I gave it. This is the boring explanation and therefore probably deserves testing first.
- Surface. The two papers do not have the same surface, and a deposit that is invisible on one might be obvious on another. It is possible something happened and I could not see it.
The honest answer is that I ran a couple of prints on each, and I need to do more.
RA-4: There Is Enough Silver After All
The received wisdom about RA-4 colour paper is that there is not enough silver in it to do silver-based process work. The silver in a chromogenic print is a means to an end — it develops, it triggers dye formation, and then the bleach-fix removes it entirely, leaving an image made of dye. Whatever is left is not supposed to be enough to build anything on.
I have had reason to doubt this before. The RA-4 mordançage work in 012 and 013 ran on the same suspicion — that there is more going on in these materials than the datasheet implies — and it paid off there. So RA-4 went into the direct toning sequence.
It works. Not marginally: it produces the strangest and most specific results of anything I tried.
Because I printed the same black and white negative — a wall of stamped clay tokens near Chinatown in Melbourne — on black and white paper in the same session, the comparison is unusually direct. Three prints, one negative, three chemistries.
I ran two variants. Developed in black and white chemistry first, the print comes out pale blue wherever the image was exposed, with a band of gold along the borders where the paper was not.
The interface between the two is the thing I keep going back to. I had assumed it would be a soft transition, and it is not — the boundary is surprisingly hard, and there is a thin white line separating the gold from the blue, as though a third thing is happening in the millimetre between them. My guess is a gradient: some concentration or potential falling off across that edge, passing through a narrow band of conditions that produce neither deposit. That is a guess made while looking at a print, not a measurement, but it is testable — masking the paper to make deliberate edges and seeing whether the white line tracks them would settle it quickly.
Developed in RA-4 chemistry first, the dye couplers still fire. A colour image forms - ignore my poor filtering. The warm border survives around it exactly like the black and white version.
Two caveats. I do not know how stable any of this is, and given that the whole process is a controlled version of a degradation mechanism, that question is not academic. And I have made very few of these. Both variants want a proper session, and if the gold border turns out to be as controllable as it looks, this becomes its own post rather than a section of this one. Suffice to say, I really like this effect, and need to understand that gradient better.
Stacking It With Mordançage
The last thing to try was combining silver mirroring with mordançage, which is arguably my most used process.
Direct silver mirroring first: poor. The mordançage that followed had no middle register. The veil either refused to lift at all or came away wholesale, taking the image with it, with very little in between. My working explanation is that mordançage depends on a fairly specific amount of developed silver being available for the copper chloride to attack, and silver mirroring has already spent that budget — either locking silver into a deposit the bleach cannot reach, or loosening the emulsion so thoroughly that it releases in one piece. Either way, there was too much silver in play and not enough control over it.
Mordançage first, indirect silver mirror toning later: excellent. The mordançaged shadows came up gold, which on its own would have made the session worthwhile. But the paper base also turned a distinct purple.
I cannot account for the purple. It has the look of a lumen print, but this print was fixed, and as I recall, fixed correctly. The image was prepared for my Beneath the Surface show a year ago and has been stable since, so something is being deposited in or on the base rather than in the image. The obvious suspects are silver liberated during the mordançage stage and re-precipitated by the toning bath somewhere it has no business being, or halide that survived the earlier processing in a form I am not expecting. Both are guesses. A print that has been through mordançage has had a lot done to it, and the number of things that could be sitting in that paper is not small.
I love the effect and I do not yet know whether it repeats — I will definitely be trying more of this.
What I Haven't Tried
Everything above is tray work: the whole sheet goes in, the whole sheet gets whatever the bath decides to give it. That is one way to use this chemistry and not the obvious one, given that I already work the other way elsewhere.
In 016 I apply chromoskedasic chemistry with a brush — stabiliser across the whole surface, then activator selectively, then developer into chosen areas to trigger silvering exactly where I want it. That is the same family of chemistry as this bath, applied by hand instead of by immersion. There is no reason it would not transfer. Brush-applied silver mirroring would mean choosing which highlights mirror and which stay paper, rather than accepting the distribution the negative happens to provide — and on the evidence of 016 it would also mean streaking, drips and over-silvered patches to control.
Two other things suggest themselves and remain untested. Masking, which came up in the RA-4 section as a way to find out what the white line at the border is doing, would double as a compositional tool if the boundary really is that hard. And partial immersion — dipping rather than floating, or drawing a sheet slowly out of the bath — would produce a gradient of coverage across a print, which if the percolation argument holds should also be a gradient from mirror through mixed to colour on a single sheet.
There is a practical argument for the brush as well as an aesthetic one. Tray work commits a full volume of thiocyanate and silver-bearing solution per session; brush work uses a fraction of it.
What Travelled and What Didn't
The recipe is more portable than expected: it worked on neutral fibre with nothing more than a longer time in the bath, on one lith-compatible paper, on RA-4 in two different developer chains, and stacked on top of mordançage. It is tuned to silver, not to a paper — which in retrospect is what you would expect from a process that is, at bottom, a controlled version of something that happens to every silver print given a few decades and bad storage.
Next: 037 · The Metal Trees — the process settled, and pointed at something.