View Full Version : Madonna and Child Tannin Experiment.

Doug K
03-17-2013, 12:00 PM
I had some over-exposed cyanotypes of this print, so I experimented with bleaching with calcium carbonate, and toning with tannin. I ended up with this sort of duotone effect where the darker regions have more of the blue coming through. The print was a few weeks old when I did the toning. I found that I was able to "save" the print from an over exposed one. It did darken a little in the weeks after doing the toning just like a cyanotype does.

The original photo is a digital image taken at the Duomo in Siena, Italy this past fall. Traditional 2-part cyanotype on Stonehenge paper. As per my typical process, the original cyanotype was initially developed in a citric acid bath before finishing up in plain water.

03-17-2013, 02:06 PM
looks great! well done, its always satisfying to salvage something which seemed lost!

the brown from the tannin really gives it a stony look

03-17-2013, 03:11 PM
Doug -

I love the duotone effect. Too many times this process results in washed out images after the tannin toning. You have shown that one should over expose a cyanotype that is intended for bleaching and toning.

Doug K
03-17-2013, 03:43 PM
Thanks Earl. I think it was from you that I first learned that a cyanotype should be overexposed for bleaching and toning, and I absolutely agree with you. It's interesting to find the detail still in the shadow areas where you thought it was lost, and working with the toning to bring it back.

Isabella, thank you! I hadn't thought of the tannin giving it a more stony look, but there it is. I think this print really shows that photography isn't always a representational art. The carving I've photographed here is in white marble, and yet presented here in sepia/blue. I know when I'm making prints, I'm not thinking of what the original subject looked like, but rather what will make the best print. I don't think that anyone who has seen the original carving will confuse it with the prints I've made of it, but hopefully it evokes a memory of what they've seen.

Tom Persinger
03-17-2013, 09:29 PM
nice print Doug! looks great!

03-18-2013, 09:02 AM
I like it as well!

03-25-2013, 06:35 AM
Very nice. The split tone effect has worked really well here. I have tried split toning a few times now and it seems to be very dependent on the paper itself; probably to do with how it is sized and buffered or what contaminants there are.

If you find a paper that split-tones easily, it is actually possible to over expose the image well, and then develop the print directly in a reasonably strong sodium carbonate bath! The process is quite 'heart in mouth' though as the image appears, splits and then disappears quickly, so you need a water bath on standby to stop the bleaching. The many images I pulled too late I now use as backing paper when I am framing good prints :)

I wondered how stable bleached prints were (just split blue/yellow and not toned, or at most partially toned). I have had one on my wall now for a few years; it gets the sun during the day too. I have seen no changes yet, so the process seems stable and should be even more so when toned.

Best regards,


03-25-2013, 03:35 PM
Interesting effect.

Doug K
03-28-2013, 09:27 PM
Yes, Evan, I agree with you. Stonehenge really works for me well, but I've found that Twinrocker works even better. I haven't an image yet on Twinrocker that I'd care to share, but it really seems to hold on to the cyanotype chemistry well. I've never thought of developing directly into the bleach bath directly, that would definitely take some courage. The effect here was done by not bleaching the print completely, and leaving some blue.

It's been my experience with the yellow/blue that they are very stable on the wall. I have one that is a couple of years old, and looks fine, though it is behind supposedly UV filtering glass. I also have syou me tannin treated prints that haven't been on the wall, but still are looking fine. Maybe I should put one up on the wall to see how it lasts...

Thanks Evan! Thank you too renon, it is indeed an interesting effect, and something to think of when you have those over-exposed prints...