Flash Index > Details (Understanding Flash)

The Flash Index can numerically score the visual appeal of a colorfully-toned coin at its optimal viewing angle.  The determination to use an optimal viewing angle for the Flash Index is key, since a colorfully toned coin can look different at various lighting and viewing angles.  The use of an optimal angle and the resulting look of a coin, is what is often captured by professional coin photographers.  This decision allows one to apply the Flash Index to professional coin photographs, which immediately allows the application of Flash Index scoring without seeing the coin in hand.  On the one hand, this is limiting in that the best way to evaluate a coin is (still) live and in hand (although movies or animations can go a long way to mitigate that limitation).  On the other hand, this agreement to score based on optimal view immediately allows one to score hundreds of thousands of coins just based on professional photographs, which allows a multi-fold increase in the possible application and sharing (and comparing) of scores.  This is where the term “Flash” comes from — it is reminiscent of a flash bulb going off on an old style camera. In other words, its the look the coin will flash at its best.

To compute the Flash Index, the obverse and reverse are scored separately on 10 characteristics.  These 10 characteristics can be separated into 4 groups: Color, Surface, Distractions, and Grade. 

  1. Group A: Color
    1. Impression
    2. Transition
    3. Coordination
    4. Credibility
  2. Group B: Surface
    1. Reflectivity
    2. Luster
    3. Gloss
  3. Group C: Distractions

    1. Speckles
    2. Spots
  4. Group D: Grade
    1. Grade

The first four items, which fall under Group A (Color) comprise 40% of the Flash Index score.  Since this was a system devised to evaluate the beauty and eye appeal of colorfully toned coins, it seemed logical that a major portion of this system to be focused purely on the color.  The next three items, which fall under Group B (Surface) comprise 30% of the Flash Index score.  This group focuses more on the coin rather than the color, which is an important consideration and needs to factor in.  The next two items, which fall under Group C (Distractions) comprise 20% of the Flash Index score. This category handles things which are a detriment to eye appeal.  You want as few speckles and as few spots as possible to attain a high score.  Finally the last item, which falls under Group D (Grade), provides a bit of professional third party input into the Index.  I recommend using this Index only with PCGS grades, since I believe they are the industry standard, and a numeric grade from PCGS gives one confidence that the coin has gone through a preliminary screening by a number of well-trained professionals. It also provides a more level playing field when comparing the score of one coin to another.  However in a pinch, I also allow NGC grades to be substituted.

Each of the 9 categories, in Groups A through C, are scored independently on each side (max of 5 points per side) to give a possible maximum score of 10 in each category.  The last category (in Group D) is scored only once for the coin (based on the thrid party grade) and ranges from 0 to 10.  This gives a possible perfect score of 100.  One then divides the computed score by 10 to get the Flash Index, which is on a 0.0 to 10.0 scale, in one-tenth increments, providing 100 possible Index values.  This fine (100 increment) detail allows for good separation of coins when judging visual appeal.

This PCGS MS65BN 1945-D Lincoln Cent scored a Flash Index of 8.7, which puts it in the Silver Class Tier. 

This PCGS MS66BN 1941-S Lincoln Cent scored a Flash Index of 9.4, which puts it in the Gold Class Tier.