Is Light Needed To Add Toning?

Temperature (heat), humidity and lack of handling are the three +++ for toning. Canvas bags, envelopes & sulfur folders are the best methods for the toning to occur in

I heard that works ^

Coins can tone in paper rolls, not just bags, if left long enough. I found several old rolls of silver halves the other day: some had serious toning, one even had verdigris. The paper rolls themselves were old and frayed. A while back, I found a '64 Kennedy with fabric toning. It has the most amazing pattern; you can even see the woven threads!

Light can play a part in the formation of toning on silver coins. Many silver compounds darken on exposure to light. I believe a fingerprint, for example, will darken much quicker in bright light than in a darkened room. However, the "rainbow coloured" toning that coin collectors find fashionable these days is caused by a thin film effect, which will occur no matter what colour the compounds are.

If tarnish prevention is your goal, then protecting a coin from the atmosphere is far more critical than protecting a coin from light. I look at my mother's silver spoon collection, which has been hanging on the wall for several decades now: the ones in bright light don't look any worse than the ones in deep shade, but the ones in the airtight cabinet are still pristine while the ones in open air are ugly and tarnished.


It's a tricky question that has long been debated in coin collecting circles.

Personally, I'd restrict using the term "artificial toning" to forms of toning that use chemicals a coin is not likely to encounter in day to day use and circulation - clorox bleach, for example, is "artificial", since chlorine gas is not something most people have everyday experience with or expose their coins to, and the resultant "toning" is physically and chemically distinct from normal silver toning.

One could perhaps use terms such as "intentional toning", but it can sometimes be very difficult to determine the "intent" of a coin's previous owners, just by looking at the coin. Just about any kind of toning can be made to look like an accident.

It might be most accurate to talk of "accelerated toning". That's where people deliberately expose coins to an adverse environment, particularly one rich in sulfur: things like match heads, crushed garlic, eggs or simply leaving it on a sunny kitchen window. There is usually no chemical difference between the toning on such "accelerated" coins and "natural" toning, but the more aggressive methods can leave additional residues on the coin that can be detected. Suffice to say that a coin that still smells like garlic, rotten eggs or brimstone has probably been artificially toned.

Yes that will work. Actually many items will make coins tone. Placing a coin in a box, bag, jar with ground up match heads will work fine. Same with parts of eggs but that gets mushy and smelly. Same with many items found around the house.
If you use the Search tab at the top and type in Toning, Toned coins, etc. you should find many posts about that subject and many possible methods of toning.
Remember that toning on a coin is in a way similar or the same as tarnishing, corroding, staining, etc. It is a chemical reaction of the coin's metal with a substance usually in a gasseous form. Some solutions too will create that toning effect. Gun Bluing solutions are an example.
The Sun does little to tone a coin unless the coin is within a few miles of the Sun of course. Light does nothing to metals but the Infra Red portions of light are actually heat and that will increase chemical reactions such as coin toning. No one so far has proven that cosmic rays from space tones coins though. Most portions of visible light will just bounce off metals but there are numerous parts of light that are not visable such as the Infra Red bands and those would effect metals as noted above.
For toning coins there are so many methods attempted all the time that it is really becoming difficult to know what is AT and what is NT. That debate has been discussed here many times too.

The mechanism for toning is well documented in the book Coin Chemistry. I suggest you buy a copy, it's a great reference book. In a nutshell, toning is simply the reaction of hydrogen sulfide and a metal. Light has nothing to do with the process.

And also the angle that the coin is photographed

That's true Carl, but the main culprit is H2S....I was trying to use the KISS program. LOL