Squeezing information out of photos - 1921 Peace dollar example 0

[RWB]

Another chat board includes an interesting observation and discussion about a 1921 Peace dollar recently sold by Stacks-Bowers. The gist is that Lot 11342, 1921 Peace Silver Dollar. High Relief. MS-64 (PCGS), OGH, sold for $3,600, which was thought to be very high for a visually unappealing coin. Some speculated the buyer thought it was a MS-65 coin. [https://forums.collectors.com/discussion/1055026/oh-my-another-crazy-1921-peace-dollar-result]

We know that for some coin types visual appeal is more important than detail quality; for others it is the reverse. For 1921 Peace dollars, design detail is generally more important that visual appeal.

In-person examination is always preferable to photos, but if it is not practical, there are techniques to draw useful information about wear, detail and color from good quality photos, such as those made by Stacks-Bowers.

In this case, I wanted to separate the surface stains/tone/tarnish etc., from damage, and also get a better view of detail. The exact processes change depending on what kind of emphasis is wanted. In the sample below, the left image is the auction original, the middle is a green channel grayscale from the original, and the right image is a composite of an inverted grayscale green channel, modified blue channel and an inverted grayscale original. Note that each image provides a clearer view of the surface or design detail, by both enhancing and minimizing ranges of pixel values.

Based on image modification and analysis results, my opinion is that the coin has above average detail, but is closer to MS-63 than MS-64; grading MS-65 would be out of the question. The detail alone seems sufficient to justify the price. The coin might also benefit from careful "conservation."

Edited April 2, 2021 by RWB

[MarkFeld]

2 hours ago, RWB said:

Another chat board includes an interesting observation and discussion about a 1921 Peace dollar recently sold by Stacks-Bowers. The gist is that Lot 11342, 1921 Peace Silver Dollar. High Relief. MS-64 (PCGS), OGH, sold for $3,600, which was thought to be very high for a visually unappealing coin. Some speculated the buyer thought it was a MS-65 coin. [https://forums.collectors.com/discussion/1055026/oh-my-another-crazy-1921-peace-dollar-result]

We know that for some coin types visual appeal is more important than detail quality; for others it is the reverse. For 1921 Peace dollars, design detail is generally more important that visual appeal.

In-person examination is always preferable to photos, but if it is not practical, there are techniques to draw useful information about wear, detail and color from good quality photos, such as those made by Stacks-Bowers.

In this case, I wanted to separate the surface stains/tone/tarnish etc., from damage, and also get a better view of detail. The exact processes change depending on what kind of emphasis is wanted. In the sample below, the left image is the auction original, the middle is a green channel grayscale from the original, and the right image is a composite of an inverted grayscale green channel, modified blue channel and an inverted grayscale original. Note that each image provides a clearer view of the surface or design detail, by both enhancing and minimizing ranges of pixel values.

Based on image modification and analysis results, my opinion is that the coin has above average detail, but is closer to MS-63 than MS-64; grading MS-65 would be out of the question. The detail alone seems sufficient to justify the price. The coin might also benefit from careful "conservation."

Why do you think “the detail alone seems sufficient to justify the price”? To my eyes, the detail isn’t special, much less worthy of multiples of what a typical example of that grade brings.

[RWB]

Inscriptions are well formed and rounded. The hair seems separated and defined. The prime weakness is in the tiara rays. Most coins, even ones with good central detail, have chisel-shaped lettering. Having neither seen the coin in person nor having spent a lot of time enhancing the original images there is always a disadvantage. The central part of this coin is the most obscured by discoloration.

Edited April 3, 2021 by RWB