[drcy]

All areas have uncertainty. What matters is that experts correctly represent the uncertainty.

There is no area in memorabilia or physics or biology or art or astronomy or religion or economics where there is 100% certainty. The key is to say you don't know when you don't know, and to know when you don't know.

Also, your label shouldn't be more specific than your knowledge. Circa 1930, or "1930s" can be a correct label, where "1932" for the same thing wouldn't be.

As I said before, I don't have specific knowledge of Conlon's photos including what sizes he's used when, but a question shouldn't be just about the white borders but the white borders with the 8x10" size. Showing pre-1910 white-bordered photos certainly is relevant and informative, but ones that are smaller than 8x10" are not the same things. The 8x10" size is very relevant and should be sorted out, as an 8x10" white bordered photo is generally associated with later time periods.

I don't know the two-year window question necessarily has great relevance to the value of this photo. For example, if the photo turned out to be made in 1918, would that alter the hobby value? I don't know that it would. Two years always was and always will be just someone's arbitrary pick. There is no objective, exact definition for what is "original," and a historic photo doesn't have to be original to valuable. There are many other factors and qualities that go into value.