Toning with Baking Soda
For day 3, I decided to keep experimenting with toning cyanotype using every day materials. Yesterday was bleach, and today baking soda. I’ve never tried baking soda because photography books always tell you to use “washing soda” and not “baking soda.” So I’ve never tried it until now.
So what’s the verdict?
Baking soda does work.
It tones the cyanotype print to a yellowish hue, but it does it at a very slow rate (which is great). The first print is a regular cyanotype, and the prints after are toned with baking soda.
At first I thought it didn’t do anything, and then the yellow appeared. For these prints, I used 3 grams of baking soda dissolved in 25 ml of water. The toning almost looks like a grayish blue, which is an interesting color.
Then I thought that the brushes were contaminated with bleach from yesterday. So I did the experiment again with different brushes (the second row shown above). The prints still turned yellow, but it’s a softer yellow compared to the one produced by bleach.
Experimenting with Exposure Time
Now that I can produce yellow using bleach or baking soda, it would be a great idea to see what tones of cyanotype can be achieved using different exposure times. If I can create a specific cyanotype tone, then I can create a specific yellow tone. I exposed my value table in increments of 1 minute—from 1 minute to 12 minutes.
But before we talk about the results, let's go over terminology. From darkest to lightest, values can be described as shadow, three quartertone, midtone, quartertone, and highlight.
Now let’s look at the results.
- At 1 minute - only the shadows are printed.
- At 4 minutes - only the shadow + three quartertones are printed.
- At 6 minutes - the midtones now have some definition
- At 9 minutes - the quartertones are showing up and have some definition
- At 12 minutes - the highlights now have some definition.
Based on tests I’ve done in the past, my normal exposure time for cyanotype is 12 minutes. At this exposure time, all the values from the shadows to the highlights show up in the print.
Why Are You Doing All These Experiments?
Someone mentioned to me yesterday, “Why not just take pictures? Why are you doing all these experiments?”
Because this is the way to gain mastery over my medium. I have to know and understand how my materials will behave under specific conditions.
In a way, what I’m doing above is like practicing the scales in piano (I used to hate doing that). It’s the same thing painters do when they paint value scales, from shadow to highlight.
The experiments will help in creating backgrounds that target a specific yellow tone, as I have done in the first image in this post.
That’s it for Day 3!
For Day 4, I’m doing one last toning experiment, and then I’m going to do some shooting (finally!).