Cathy,
I must admit that Steven's arguments have me convinced it is a modern fake.
Re. the original tints - Ding Erzhong did not, so far as I know, grind his own colours. So he would have bought them from purveyors of artist's materials, of which there were a number on Liulichang St. in Beijing, according to YF Yang (This is also the location of the private kilns and artisans doing the enamelling on glass, in the late 19th & early 20th C., again according to YF).
Since the Ye Family (Apricot Grove Studio) continued working till 1950, and then taught students from 1953, it is totally plausible that the same tints are still available.
They are very probably more costly than the modern made colours, but if someone were to try to fake a bottle which, if successful, could fetch US$10K - 50K; he or she would definitely spend the extra funds to make it look the part. As they say, you have to spend money to make money. There was a program on British TV during the 1980s/1990s, about a British antique dealer and lovable rogue with a heart of gold, Lovejoy.
There were all sorts of techniques for aging and faking. I am sure some is made up, but we know there are successful forgers out there.
In Chinese Art, look at Zhang Daqian, who forged superb fake Northern and Southern Song paintings and Ming, as well. He left a book to document the fakes, so he would not adversely affect Chinese Art History after his death; but how many are so 'virtuous'?
I must say I'm 0 for 2 with this bottle - First, I thought it could well be Ding's work; and I was wrong. Second, I was positive it was at least same period as Ding; again, wrong.
Sorry.
And yes, the sun can age it, and putting 6-10 or more corks and shaking the bottle for hours, might also give realistic wear...
