top of page

The Chiba System A Safer Way to Print with Gum?

I tried gum bichromate a few years ago but gave it up because potassium dichromate is quite toxic. Hazardous chemicals just don't fit with the way I like to work in the studio—messy, intuitive.


ree

Rethinking Gum Bichromate

 




The Chiba System was developed by Norwegian photographer Halvor Bjørngård as part of his 2007 master's thesis at Chiba University.

 

Inspired by cyanotype, he explored how ammonium ferric citrate (a much safer iron salt) and free radical developers like ammonium persulfate could replace toxic dichromate — and still harden gum arabic with UV light.


ree

What's Different?


In classic gum printing:

You mix gum arabic + potassium dichromate + pigment

You expose it to UV light

The dichromate hardens the gum where the light hits

Then you wash it, and the unhardened areas dissolve away

In the Chiba Version version:

You mix gum arabic + ammonium ferric citrate + pigment

BUT — since AFC doesn't harden the gum by itself,

You also add ammonium persulfate (a much less toxic oxidizer)

During exposure, light triggers a chain reaction that hardens the gum in place.So it's still a light-hardened process — just with a different chemistry


Since we're not using potassium dichromate (the traditional chromium-based hardener), we need a new way to “lock in” the image. That's where ammonium persulfate comes in. When exposed to UV light, it triggers a chemical reaction that hardens the gum and binds the pigment to the surface


ree


Toxicity Comparison: Potassium Dichromate vs Ammonium Ferric Citrate & Persulphate


 

Potassium dichromate is a highly toxic, carcinogenic substance that poses serious health risks—and has a harmful environmental impact. In contrast, the Chiba System uses ammonium ferric citrate, a non-toxic compound approved for food and pharma use. Ammonium persulfate, while not entirely harmless, is far less hazardous; with basic precautions like ventilation and protective gear, it's safe for studio work. By replacing dichromates with iron-based compounds, we reduce health and environmental risks



ree



This recipe comes from Halvor Bjørngård's original thesis. I've tried it a few times and, while I've gotten some promising results, the process isn't always consistent. The outcome can vary, and I've been adjusting parts of the formula. Halvor himself noted that this gum-based method is still in an experimental stage — so some unpredictability is part of the process for now.


ree
ree


With over 600 students, the Alternative Processes Academy has become a thriving hub for those passionate about historical experimental, and eco-friendly processes.


Explore 14 processes (and their many variations) on different surfaces — through 49 in-depth video lessons and guest lectures.


Each lesson is grounded in research, practice, and a deep respect for the medium.

 

What you'll get:


Lifetime access to all video lessons and future updates

Guest lectures from leading artists and experts

Downloadable guides, cheat-sheets, and reference materials

Access to our private community for support, feedback, and collaboration



Reduced Tuition to celebrate 2 years of teaching



 
 
 

4 Comments


chat
Nov 03

Bedava chat sohbet odaları eşleştirme özelliği, sizinle aynı ruh halini ve merakı paylaşan insanlarla eşleşmenizi sağlar.Rastgele görüntülü ve yazılı sohbet yoluyla dünyanın dört bir yanından ilginç insanlarla tanışın.Seni anlayan insanları bul.Basit bir "merhaba!" ile başlayan dostlukları keşfedin.İlgi alanlarınızı paylaşın, samimi sohbetler edin ve gerçek hissettiren bağlantılar kurun.

https://sohbetbe.blogspot.com/2025/02/sohbet-odalar-tansma-amacl-hangi.html

https://askyeriniz.blogspot.com/2025/02/cinsel-sohbet-ne-anlama-geliyor.html

https://livechattt.blogspot.com/2025/02/uyeliksiz-sohbet-nostalji-yenilik-ve.html

https://gabilessohbet.blogspot.com/2025/09/gabile-sohbet-cevrimici-arkadaslar.html

https://soh--bet.blogspot.com/2025/02/gabile-sohbet-odalar-tansma-amacl-hangi.html

https://yetiskinchatt.blogspot.com/2025/02/yetiskin-sohbetle-harika-bir-dostlugun.html

Like

chat
Nov 03

https://www.gevezeyeri.com/kamerali-chat/ Ücretsiz rastgele kameralı chat kameralı chat odaları kameralı sohbet odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/yetiskin-chat/ Ücretsiz rastgele yetişkin chat yetişkin chat odaları yetişkin sohbet odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/geveze-chat/ Ücretsiz rastgele geveze chat ve geveze chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/ankara-chat/ Ücretsiz rastgele ankara chat ve ankara chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/goruntulu-chat/ Ücretsiz rastgele görüntülü chat görüntülü sohbet görüntülü chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/cinsel-chat.html Ücretsiz rastgele cinsel chat ve cinsel chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/chat/ Ücretsiz rastgele chat ve chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/mobil-chat/ Ücretsiz rastgele mobil chat ve mobil chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

Edited
Like

chat
Nov 03

https://www.gevezeyeri.com/ Ücretsiz rastgele sohbet chat sohbet odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/bedava-chat/ Ücretsiz rastgele bedava chat ve bedava chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/uyeliksiz-chat/ Ücretsiz rastgele üyeliksiz chat ve üyeliksiz chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/ucretsiz-chat/ Ücretsiz rastgele ücretsiz chat ve ücretsiz chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/istanbul-chat/ Ücretsiz rastgele istanbul chat ve istanbul chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/izmir-chat/ Ücretsiz rastgele izmir chat ve izmir chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/diyarbakır-chat/ Ücretsiz rastgele diyarbakır chat ve diyarbakır chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

https://www.gevezeyeri.com/bursa-chat/ Ücretsiz rastgele bursa chat ve bursa chat odaları sorunsuz yeni kişilerle tanışma imkanı sağlar.

Edited
Like

Reading the ISKCON Bhagavad Gita in Kannada PDF feels like having a spiritual teacher by your side. ISKCON’s commentary adds depth and explains every verse in a relatable manner.

Like
bottom of page