Sunlight/Daylight and developers

I've always noticed it is recommended to store stock solution (or any mixed b&w developers) in an amber or opaque storage container.

What is the degrading process that occurs when developers are exposed to daylight?

Are all developers affected?

I need to mix up some Xtol (for replenishment) and am out of the brown storage containers at the moment. Common sense tells me not to play with fire and wait till I can pick up a two 1/2 gallon containers (I have a few 1 Litre bottles for the extra) but I've always wondered about what it is that causes issue.

Developing agents oxidise slightly with bright light, the higher the UV content the faster.

You can store in any colour bottle even clear glass as long as you store in a cupboard, drawer or unlit room/closet.

Ian

Thanks once again Ian.

How does the oxygen get in there from sunlight. Is there some reaction that occurs?

Unless you use water that's just been boiled & cooled there's always some dissolved gases in water, CO2 and Oxygen etc. This is one reason that many older books tell you to use boiled water to make up chemistry,

UV light itself can cause chemistry to break down,

Ian

"Amber bottles" is one of the most persistent myths, because when the myth has some truth to it, it's very hard to bust.

Usually, amber bottles cause more harm than good, because with clear bottles, you can easily examine the solutions for color changes and gunk which can give you a hint of their condition. In 99,9999999% cases, developers are not stored in a bright light (such as sunlight or specially high-level fluorescent lighting) for long times, so there's no need for protection against light. If they are in your darkroom and get only occasional room lighting, there really is nothing to worry about, even if you want to involve a huge safety margin. This has been confirmed many times here by chemistry experts, even saying that chemistry at Kodak was stored in clear bottles in room lighting, but the myth about the importance of amber bottles still goes on.

Much more important is displacing the air as well as possible. For this reason, I suggest, as always, clear PET bottles that can be squeezed as I show here: http://www.youtube.com/watch?v=hdu4cCOrf3I . But this suggestion always faces some criticism due to beverage bottles used.