A most exciting acquisition to my world of making art! A DIY UV light table for making cyanotypes, built most-lovingly by my Dad as a Christmas gift. The instructions we followed were by YouTuber Mat Marrash (video here) and it works amazingly!
Now, I knew that as a responsible artist I would need to make test strips to know how long the paper would need to expose under these new lights, so I looked up how that is usually done for cyanotypes. I have done test strips before, in my darkroom class and in the alternative processing class where I first learned cyanotypes, but you know, I wanted to make sure there wasn't anything else important I needed to know for testing a DIY lightbox.
So I found this very informative page from a UK cyanotype website that gave clear and simple instruction on how to make a "step test," as they call it. I didn't do it exactly how they did, with a little strip of paper taped down, clear lines drawn out, and I actually forgot to test it with a transparency over the paper, but the part that I was focused on was the note that said, "If you look at the image above [on their page] you can see that after step 12 (12 minutes exposure) it doesn’t get any darker. This is what you are looking for, there is no point to expose your prints longer than this as you have reached the maximum darkness." Great, maximum dark for minimum time, that's logical!
Time for my first test strip! Having no clue how long it would actually take to expose my paper with these UV lights, I tested on the long side with around 20 steps, from one minute to 20 minutes of exposure.
After I developed it and let it dry and darken towards it's final state, I found that I really underestimated the power of the UV lights! As you can see in the picture above, it's about as dark as it's gonna get around 5-6 minutes. You could argue that it does get progressively darker the longer it exposed, but.. Not enough to be really noticeable. So, going by what my source said, 5 minutes is as long as I should need for a print, right? Awesome. I then did a smaller test with 30 second increments up to 5 minutes, and that showed the range of timing and exposure, better.
Next I chose a negative to try printing! I picked my one and only 4x5 negative that I took in a photo class as the first experiment, since it's a large negative for contact printing and it's rather "thin" so a lot of light can get through and the exposure wouldn't be long. Plus I just love it and wanted to print it first.
I made another test strip, this time with the negative and glass over it, and did the same as the previous smaller strip: 30 second increments for 5 minutes. As you can see, most of the steps are very much not enough exposure time, but the 5-minute step, farthest to the right, looks okay. So I made a whole print with a 5 minute exposure.
I was so happy to see my picture in positive, and I could look at all the leaves and sticks in the scene. But I couldn't help think it still didn't feel quite right... there was a lot of white, washed out areas in the highlights, and I knew that there was more detail to see in the negative. This is when I had the epiphany.
The tip from the UK website is correct, that once you know how long it takes to reach the darkest value, you don't need to expose any longer, BUT that is for when you are only making silhouettes, such as this leaf print I made:
The only inhibitor of light reaching the coated paper is the object. But printing from a negative, it is FULL of different values that block light, plus the negative material itself. So the maximum dark that I found on the naked test strip is actually the minimum time I should expect the negative to take to expose. My test strip for the photo should have started at 5 minutes, and gone up. Once I came to this realization, I knew it was actually obvious that that's how it works, but my learning style is visual and kinesthetic. I have to SEE and DO it myself for it to stick.
Now armed with my knew knowledge, I made another test strip, this time starting at 4 minutes and going up 8, and BOY did it look so much better! There are details in all those highlights that were washed-out before, and the whole scene feel dark and moody like the place where I took the photo. Now I just had to decide which step was Just Right. 8 felt a bit dark and lost some detail in the shadows, but 6 was still too bright on the top of that rock.
7 it is! One more print later, and we have the best print yet. Isn't it lovely?
Verdict: the light table works perfectly, and I am still learning!
Bonus material!
I will never get over how much the print changes. It appears like magic from... not much!
