I’ve been thinking of making some cyanotypes after reading an article in Amateur Photographer a few weeks ago. Then someone turned up at my local camera club with some excellent examples, really nice work. I think their creator said she’d read the same article.

One thing puzzled me and that was that the process is mainly sensitive to UV light, yet a common technique is to hold things flat with a sheet of glass. I thought plain glass blocked UV so wondered if longer exposure times would be necessary when using a glass sheet. There was a brief discussion at the group about this but I was left none-the-wiser, really.

I’ve now ordered the chemicals to have a go at this and have done some research (a quick Google!) to understand this better for when I get around to creating my own cyanotypes. It turns out that normal glass blocks nearly all UVB (which causes sunburn) but allows 75% or so of UVA to pass through (you won’t get sunburn from UVA, but it can cause skin cancer). The UV spectrum consists of UVC radiation (200 nm to 280 nm), UVB radiation (280 nm to 315 nm) and UVA radiation (315 nm to 400 nm) according to a research paper I found.

The research indicates that the sensitised paper is sensitive over the UVB range, but also to UVA until you get into the visible wavelengths. This suggests that the glass does increase exposure times somewhat… it will be interesting to experiment with the cyanotype process. Now I just have to find the time to do so.

2 thoughts to “Cyanotypes”

  1. Hi Steve,

    During winter in this part of world it’s a bit difficult to produce Cyanotype prints. Although using a UV box it makes it possible. Nonetheless they’re quite expensive to purchase one. My little project for Christmas artwork workshop, I’m going to try using a Nail Dryer. Yep a nail dryer! These devices emit UV light albeit it’s limited to a small area. It should be enough for making Photograms or 10x15cm prints for Christmas card. That’s my goal (if doesn’t work out I guess one of my lovely daughters shall receive a new gift for Christmas!).

    This Thursday the Nail Dryer should arrive. It has the added advantage of a timer built-in 30/60/90 seconds. I’m not sure at this stage of course how along the exposure will take, if it works at all. I also looked into this project using UV tubes in an old flat bed scanner – If the Nail Dryer works, I guess I can build the same project will LED UV modules from Ali Express –

    If it works, I’ll post a blog entry or video on my site at some point

    Best Regards,

    1. Thanks for your thoughts. I have the same problem… not much sunlight at all in recent weeks so I’ve not even started looking at doing anything with the gear I’ve bought yet.

      As for UV sources, my background is in electronics and I have a UV lamp in an EPROM eraser I bought nearly 20 years ago. It’s a fairly small lamp, but probably bigger than in the nail varnish curing device. You can apparently buy spares from places that sell tropical fish and the like as they’re used to sterilise fish tank water. I also bought a UV torch from Banggood that I’ll probably experiment with, too.

      I’ll try to remember to check your site from time to time to see how you get on.

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