Legacy Pro Indicator Stop Bath for Black & White Film & Paper (16 oz)

Unopened bottles of Legacy Pro Indicator Stop Bath have a very long shelf life, often considered indefinite if stored properly in a cool, dark place. This is because the main active ingredient (acetic acid) does not degrade significantly over time when sealed. The indicator dye might fade eventually, but that doesn't affect the stop bath's effectiveness. However, once opened, the shelf life can decrease due to exposure to air and contaminants. If you're unsure whether it's still good, you can test it by mixing a small working solution and adding a bit of used developer—if the color changes from yellow to purple, it's still active.