A 3-Year Durability Test: Copper Sulfate Bleach Still Working Perfectly!

[mohmad khatab]

Hi everyone,

I have a fascinating chemical observation to share. After being away from my lab for 3 years, I tested a bleaching solution I had prepared back then, and to my surprise, it still works with full efficiency!

The Formula:

• Copper Sulfate: 25g
• Ammonium Chloride: 25g
• Deionized Water: 500ml (Dissolve at a temperature near boiling).

Usage Instructions:

• Time: 6 minutes.
• Temperature: Should not be less than 32°C.
• Capacity: This 500ml batch is enough to bleach 10 rolls of film.

Important Technical Notes:

• No Pre-bleach or Post-bleach "Solutions" needed: This specific formula does not require a Pre-bleach solution or a Post-bleach solution.
• The Water Wash: It only requires a hot water wash after development and another after bleaching. The water temperature must be at least 38°C for a duration of no less than 3 minutes.

The Hardware Challenge: Unfortunately, while the chemistry survived, my film scanner is out of service because I lost the cables, the power adapter, and the Linux software configuration. I am working on getting it back to life soon.

Has anyone else experienced such longevity with this specific Copper Sulfate / Ammonium Chloride mix?

Best regards,Mohmad khattab

 

[Yezishu]

Thank you for the experiment. I'd like to ask if there's a source for the 32°C. requirement? This might be from an earlier experimental post? It seems dangerous for some films; would this formula work at 20°C?

 

[wiltw]

Depletion of developer is due to 'oxidation' (vs. 'reduction') chemical process while in storage, yet solutions that do not undergo 'oxidation' are long lived.

 

[Spektrum]

Thank you for the experiment. I'd like to ask if there's a source for the 32°C. requirement? This might be from an earlier experimental post? It seems dangerous for some films; would this formula work at 20°C?

How can a temperature of 32°C damage the film if the C-41 process is a high temperature process (38°C) ?