Brownies get the blues – Combining Van Dyke brown and cyanotype

This sort of emerged as I was playing with, and I’m actually quite happy with what I ended up with – unintentionally. It’s a combination of Van Dyke brown prints and cyanotypes that allows for the image tone to be set at virtually any point on the ocher-cyan axis. It’s also quite easy, reasonably quick, affordable and can be done with a high degree of consistency.

To clarify up front: this is not the well-known technique of printing a Van Dyke on top of a cyanotype. The results of that approach can be very striking and spectacular indeed. What I’m going to show you below is more conservative and middle-of-the-road. Not less pretty, in my view, however. The problem of combining Van Dyke and cyanotype is that they are not chemically compatible, so in printing one over the other, you destroy either or both of them to an extent.

But it doesn’t have to work that way. What if we protect the first print as we put the second one on top? Look, I’m not the first (by far) to think of this. There are people working on multicolor-color cyanotypes, for instance, sometimes with quite gorgeous results (be sure to check out this recent experimental work), and these approaches all rely on printing the layers in a way that ensures chemical resilience of the underlying layers to the layers deposited later on top of them. What I’m going to show here is very similar – but I combine Van Dyke brown with Cyanotype.

And no, combining processes isn’t unique, either, I know. Plenty people have been making ‘gum-overs’ using cyanotype as a cyan layer. Or combinations of Pt/Pd prints with other processes. Etc. etc. So my ‘invention’ doesn’t really deserve the name, as it’s probably not new at all, and it’s also a kind of obvious step within amply know territory. But it’s still nice – and quite practical.

So, back to that issue of chemical stability. The route I chose emerged more or less automatically from messing about with a negative (or actually a set of near-identical negatives) I’ve shown before. I was having fun with those negatives and they seemed to fit just in the density range that make presentable cyanotypes and Van Dykes. So I was playing with those processes, and specifically doing some toning on them – especially on the Van Dykes.

One of the toners I wanted to revisit for Van Dyke was the odorless thiourea sepia toner I also posted about recently. So I did this quick little experiment, toning a Van Dyke in sepia:

It’s kind of odd to tone a Van Dyke brown print, which is kind of sepia looking as it is, in sepia – but there’s sense to it. As illustrated above, this offers some additional hues that may work for some images. Note also that interestingly, direct toning is (1) possible and (2) results in a seemingly cooler print, which is counterintuitive – but useful. As it turns out, this direct toning is very much incomplete: only a small part of the image is actually converted to silver sulfide, so there’s just a little sulfide being added to the print. For amusement’s sake, i also tried direct toning with (smelly) sodium sulfide toner, which produces a lighter hue that’s somewhere between the indirectly toned sepia print (the yellow one) and the middle one.

The indirect approach is the most useful for combining with a cyanotype layer, since the indirectly toned print should consist virtually entirely of silver sulfide. And silver sulfide is very chemically stable, so it will resist the attack of the somewhat aggressive cyanotype chemistry. This is contrary to the pure silver image of an untoned Van Dyke brown print, which would be entirely erased by a cyanotype sensitizer that’s brushed on top of it.

For the cyanotype part, I also did some toning experiments, but I have to admit that I always struggle with cyanotype toning. There are so many things about it that I just don’t like. The hues always come out muddy and flat; it’s very difficult to get anything with any liveliness apart from the original cyan. At the same time, getting something neutral grey is at least as difficult and perhaps even more so, so to me, it feels like I’m always stuck in the middle. Then there’s the issue of staining, with most of the more effective toners for cyanotype pretty badly (often horribly) staining the paper. Finally, toning cyanotypes is often a slow process. I’m consistently short on patience, so that doesn’t suit me very well.

I think there are ways to overcome these problems, especially in the area of metal replacement toners. The Photrio thread I linked to earlier is very promising – although some of the chemicals used are kind of…nasty.

Two things that are quite quick, easy and dependable with cyanotypes, however, are ‘copper implant’ toning (I made up that term, sorry) and bleaching. Combined, they also have an interesting effect. The ‘copper implant’ thing involves nothing more than briefly dipping a cyanotype in a dilute solution of copper sulfate. What apparently happens is that copper is deposited among the Prussian blue pigment matrix, and the visual change in the print is that it becomes slightly duller (less saturated) and very slightly more cyan.

Bleaching a cyanotype in first instance turns the image away from cyan and strongly towards magenta (a range of hues I find absolutely stunningly beautiful), and ultimately bleaches out the entire image into a very pale yellow hue. In multi-colored cyanotypes, this is sometimes employed combined with very strong overexposure to make a yellow image layer.

Bleaching can also be combined with the copper treatment mentioned above. In this case, a high-contrast result can be achieved with a more muted, dull blue in the shadows and white or pale greyish highlights.

I took all of the above and extracted two things from it that I figured I could combine, a sepia-toned Van Dyke brown, and a copper-implanted, bleached cyanotype:

I figured that combining these prints would give an interesting result that would boil down to a split-toned print, a bit (although much more subtle) like the recently invented FerroBlend process. Well, that didn’t really pan out, and I got something different that was nonetheless quite interesting: a fairly neutral-toned print.

This was really a kind of “what does this button do” experiment, where the penny dropped, so I took one of the sepia-toned Van Dykes I had made previously and crudely aligned a cyanotype on top of it – which turned out to work quite well. At that point, I figured I might as well and try to control the thing, and by varying exposure of both ‘halves’ of the print, I could quite easily make a range of prints spanning the gamut from one end to the other:

As you can see, the total luminosity/brightness wobbles a bit as I was experimenting my way through it all. But the main principle is quite consistent: this method allows for a quite consistent mixing of a brown/yellow image and a cyan/blue image on top of each other. As a bonus, there’s very little stain in the unexposed areas. There’s a little, and I think with careful processing this can be further minimized.

For those interested in trying this on for size, here’s the workflow, which really is quite straightforward. The number of steps may seem intimidating, but the process isn’t very complicated, nor does it take very long.

1. Make a regular Van Dyke brown print.
2. After fixing and thoroughly rinsing the print, bleach it with a bleach made of potassium ferricyanide and potassium bromide. There are plenty of formulas online and the quantities actually don’t really matter. Bleach back the print entirely until only a faint image is visible. This shouldn’t take long; maybe a minute or two, tops.
3. Tone the print with sepia toner; I prefer thiourea sepia. You could experiment with the hue, although generally the hues will be overall much lighter (more yellow) than you’ll typically get on silver gelatin prints.
4. Rinse the print, then soak it in a weak solution of citric acid (e.g. half a teaspoon to a liter of water) for a few minutes. Wash the print for a few minutes after this, changing the water a couple of times. This is to ensure that the alkalinity of the sepia toner is removed as much as possible from the paper so it doesn’t interfere with the cyanotype image.
5. Dry the print; I generally just blot it with a towel and then blast it with a hairdryer because it’s quick.
6. Coat the cyanotype sensitizer right on top of the sepia-toned Van Dyke brown print (which really is yellow, not so much brown at this point). Dry the sensitizer; you may see it react a little with the paper, forming some Prussian blue without any exposure. This shouldn’t be excessive; if you see a lot of blue staining occurring and/or in an uneven pattern, try a different type of paper.
7. Expose the cyanotype, then process as normal by soaking a few times in weakly acidified water.
8. Now, soak the cyanotype print in a weak solution (let’s say 1% w/v or so, maybe less, stronger is certainly not necessary) of copper sulfate. This solution can be reused especially if you add some sodium citrate to it as well. You’ll notice the cyanotype immediately becoming slightly dull. That’s good. After a minute or so, rinse the print.
9. Now bleach the cyanotype to the extent you prefer. For the bleaching, any kind of alkaline bath should work; typically something like sodium carbonate or ammonia (which smells, but it doesn’t have to be very concentrated). The examples shown on this page were bleached quite extensively in a rather strong/fast bleach.
10. Once the print reaches the hue you’re looking for, rinse it for a few minutes and let dry. Done!

The overall lightness and hue/color can be controlled by varying the following factors:

• Exposure of the Van Dyke brown; a longer exposure will make a denser image, which translates into more yellow/ocher in the final print.
• Exposure of the cyanotype print; a longer exposure will shift the hue to more cyan.
• Exposure of both the Van Dyke and cyanotype will control the overall density/lightness.
• The extent of bleaching controls the cyan/yellow balance as well as the hue of the cyan image.

Put together, these factors make for a very flexible process that can yield quite saturated images as well as near-neutral grayscale prints. Happy experimenting!