Message:

<p>[QUOTE=&quot;BadThad, post: 3744807, member: 17261&quot;]When they can physically see something on the coin, they can direct the IR beam to that spot. At that level of surface contamination (where you can see it with your eye), FTIR works well. However, it&#039;s more of a conformational determination to what they see visually. PCGS sees a lot of coins, they know what adulteration looks like. </p><p><br /></p><p>The detection is done by spectrum subtraction. For example, you move the beam to a clean area (baseline), take a measurement and save the scan. Then you move the beam over to the suspect area and take another scan. The FTIR software then subtracts the two and if any peaks are indicated you have a hit. The quality of the hits are really only decently identifying if you have a reference spectrum. In the case of an unknown, it&#039;s basically a jigsaw puzzle of complicated information where you can only infer, derive and guess.</p><p><br /></p><p>Yes, I have tested a VC coated coin on our ATR and it was undetectable. However, a drop directly on the ATR diamond is easily detected. With ATR being so weak with a reflected, thin layer, it just couldn&#039;t muster enough to give me anything.</p><p><br /></p><p>I have had quite a few people tell me privately they have had VC conserved coins successfully graded under the regular and secure tiers. I don&#039;t know the details of what they did.....but they were excited enough to want to tell me.</p><p><br /></p><p>Obviously, I don&#039;t much care - but I do enjoy spreading some knowledge. The bottom line with ANY TPG submission, there are NO guarantees.[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in