3 image solargraphy

 Solargraphy is the process of capturing the movement of the sun over an extended period (weeks, months years).

It consists of a can, either a self made one from a beer can or one bought from https://solarcan.co.uk/ and a a black and white darkroom paper. 

The can act as a pinhole camera and if left for long enough will form an image showing the sun moving across the sky.

I tended to make my own cans, largely because I wanted to leave them in public places, and often they would disappear, or get knocked off. 

While I loved the results and efforts, I decided to get ambitious and do a colour version. 

3's the magic number

So how do you take a colour solargraphy you ask? Well you cannot just put colour paper in (well maybe you can, but I did not investigate ). Instead the intention was to use old technique of trichromatic photography.

Before the age of good colour film, to get a colour image, you had to take 3 black white images with a blue, red and green filter seperately in front. These images could then be combined by displaying them with reverse filters on say a magic lantern.

When done well the results could be stunning, and with modern tools like photoshop we can combine them into one image. One of the best proponents was  Sergey Prokudin-Gorsky His colour images of pre-revolution Russia in full colour show a world of vibrant colours, where we used to thinking the past in hues of grey.

So how would I use this on my solar cans. Well the idea was to mount 3 cans together, each with a colour gel in front of the lens. After the set period, I would process each image to create a colour result.

Because of the size, I decided to mount it looking south on the side of my house

The results

Red

Green

Blue

And this is the final processed image

OK, not exactly what I was hoping for. In hindsight, the different transmission rates of the gels may of caused an issue.

If I was going to do it again, I may try shorter exposures but with one device (such as the solar puck). This way I would bbe more precise in positioning, or maybe better filters. 

Also maybe my processing could be improved. Still it is as far as I know the only attempted color solargraphy image.