Q/ I opened my cyanotype kit several months ago and a sort of mould has developed in solution B (Ammonium ferric citrate). Is it serious, Doctor?
A/ Nothing serious! You can limit its development by keeping the bottle in the fridge, or simply filter the solution when the mould develops. I use a washable coffee filter and a funnel for this (a paper filter will absorb most of the liquid and may tear).
Q/ I’m looking for a community of enthusiasts to ask my questions to
A/ There are several groups on the different social networks. You can find me on the CyanotypeProcess Facebook group. These groups are full of enthusiasts ready to answer your questions.
Q/ Which UV lamp should I choose?
A/ There are as many answers as there are cyanotypists, so I’m just going to give a few hints and tips. You can choose to buy a lamp and hold it between two stacks of books to expose your prints, or make a height-adjustable stand if you’re a DIY enthusiast, or even make your own lamp by buying the components (LED ribbons or UV tubes). In any case, be careful and don’t stop at the description of the lamp or bulbs: most ‘UV’ lamps on sale are simple ‘black light’ lamps. That’s great for evenings out, but it’s no good for cyanotypes… Be sure to check the wavelength emitted: it should be close to 365 nm. If it’s around 400 nm, forget it! Also beware: some lamps sold for 365 nm are designed with a mixture of 365 nm and 400 nm LEDs. If you spot a model half the price of the others, beware.
Q/ All these explanations are very nice, but what kind of lamp should I buy?
A/ I bought an Everbeam 365 nm 100W lamp on the internet for 90€ and I’m very happy with it so far. There’s also a 50W version for 56€ but that means a longer exposure time. Another option: you can find a second-hand tanning lamp with tubes, but this is becoming rare (I bought mine for €50 in 2013). Look for a model with 4 tubes about 30cm long, that’s ideal: but be careful: replacing a tube can be expensive!
Q/ Which paper should I choose?
A/ I’ll start by explaining what to avoid! Paper that’s too thin (80g printer paper) will be very difficult to handle without tearing when rinsed in water. You should also avoid all chemically-treated paper. When in doubt: try (it’s the golden rule), but don’t buy a 500-sheet pad before you’ve seen the results… A good paper to start with is Canson Montval 200g: you can find it in pads at a good price. As a general rule, watercolour paper is a good choice.
Q/ Which brush should I choose?
A/ I recommend a 3-4 cm wide brush. I started with a foam brush supplied in my first cyanotype kit, and I’m finding it hard to do without! You can also use a fairly fine brush. Others use a glass rod to spread the solution on the paper, but I’ve never tried it.
Q/ I have an enlarger that I use for film photography: can I use it to print large format 24×35 negatives?
A/ I’ve never tried, but from what I’ve gathered from my research, it’s not a given. The condensers and lens of your enlarger are certainly treated to filter out UV rays (except for very old models), so you’ll need to find a UV lamp that’s powerful enough and compatible, and the exposure times will probably be crazy and the results not very good. But if you get the chance, give it a try and share your experience!