Example of a cleaned coin

Same coin, different light. The harsh bright led washes out the hairline surface damage while the less powerful incandescent amplifies the damage.

 

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Nice photo trick to show it. Thanks for the post.

 

An educational post. Thanks for sharing. Your photos certainly show the difference between using incandescent vs. LED lights. I'm assuming it would be essentially a similar effect of these two different lights when using a hand loup for grading ... and that's why incandescent is usually recommended.

 

lighting can either hide or enhance issues of a coin just depends I gather on what type of lighting you use

for me, I use a LED desk lamp seems to do alright for photos

 

Everyone to be clear there are alternatives such as as broad spectrum led lights. Mine is a common overhead ballast style in the 4000 k range (white-blue). I'm not saying all led lights are terrible for refracting light from coins. This is my observation with my equipment. Just fyi.

 

Nice demonstration!

 

Nice display of light effects. Are they both the same Kelvin and comparable wattage?

I was working this out the other day, it's not the light per say, it's the CRI difference, if you take an incandescent, a LED ,and a halogen bulb of comparable kelvin (2700K) all 3 the same color of light output, it still won't function visually similarly.
Imagine, the sun rises at approximately 1800 Kelvin and changes from red to orange to yellow and to white as it rises to over 5000 Kelvin at high noon. It then goes back down the scale as it sets. If it went higher than 5000K it would appear as a blue light source.

This is flawed example unless you match the light color and wattage (75 watt incandescent, 53W halogen, 14W LED) the only real difference between the 3 bulbs at that point is the CRI, and the incandescent has the best CRI 97-100, followed by the Halogen, then finally the LED has the worst. All are at least 80 and "satisfactory" according to standards. Incandescent CRI is the standard all other light bulbs wish to one day achieve.

Apples to apples, as far as the color of the light Kelvin, warm or cool, and output being equal,
there will still be a washing out effect due to the much lower CRI of the LED.

These pictures can be achieved by simply using a incandescent bulb that's normally 2700K or a bit lower, and an LED bulb that is 5K or higher. you'll get yellow light on one and white on the other and this will "appear" to be the drastic difference, it is, BUT this isn't why the hairlines are pronounced or muted.

Why is CRI so important in artificial lighting? because our eyes are used to seeing things the best in natural light, when light is "off", we are "off". it's abnormal and the more unnatural it is, the less color it renders, or reflects as true viewing.
kind of like color blindness in a way, a color blind person will look at that picture and well, I don't know what they would see, because I'm not color blind, but they wouldn't see what we see. Ok, lets say that odd lighting in a parking lot full of high or low pressure sodium lights where no colors look "right" at all, that's LOW CRI.

I'd really like to see this again, apples to apples with just the CRI as the difference. I think it loses something knowing that the Kelvins don't match which is why it goes from yellow to white.

 

That's entertaining. They are not the same Watts and they are not comparable in lumens. Both lights were at the same height and angle. The led is comparable to about 400 watts. But LEDs output much more lumens per watt. The LED is also into 3 to 4k range. It is a 30 watt LED ballast Style. The incandescent bulb is a simple 60 watt light bulb. I would guess in the 7w2500 K comparable range. I am pretty confident that it is the lumen output that contributes to the effect. I see no other reason. I am not sure if the Kelvin contributes.

 

Also... I would like to compare the same situation to natural sun light now, after reading your post. I will do the same demonstration tomorrow in ambient light and also in the solstice light. Weather permitting.

 

Bad news. Well try again Saturday..

 

That is the best demonstration I have seen to illustrate the affect lighting will have on a coins image. Well done.

 

Sorry about the double post. I think I fixed it.

 

I thought it was worthy of sharing. I was surprised myself. It's why I posted it.

 

Halogen is also recommended by cgc's. I've yet to play with that.

 

Of a well worn coin........

 

Also, I don't think it is the color index because this anomaly can be seen in hand under any light source. Remember, what your seeing is is a digital representation of a lighting anomaly compounded by many factors of digital imaging and cross platform compression. But I saw it for my own eyes first hand and I can assure you the effect is equal to or better than "as in hand".

 

The coin is 'fried' anyway.......

 

Yes it is

 

Yes it is. Do you want me to scuff a MS for you? I will if it's required to conclude this observation.

 

So direct sunlight obviously shows the details of damage but it was. IMO, not as dramatic as the incandescent light. The first image is the direct sun light and the second is the ambient sunlight. I found myself rotating and tilting the coin to highlight the damage. The sun was at an angle of about 70 degrees. Similar to the angle of the shop lights I used originally.