#Measuring the Center of a Card

4 messages · Page 1 of 1 (latest)

floral radish
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Hello, hoping for someone to breakdown some geometry logic for me. I've been collecting cards for a while, and one of the biggest aspects is finding a card in perfect quality, which includes perfect centering. Several companies sell the attached product. These tools assigns ratios to measurements from opposite edges (e.g., left-right, top-bottom) to determine how centered a card is. I'm confused by how the ratios are calculated and why certain ratios are considered better than others. For example, why is a measurement of 10 on the left and 7 on the right considered a passing ratio of 59/41, while a measurement of 2 on the left and 1 on the right translates to a less favorable 66/34?

Attached are images of the grading tool and the ratio percentages breakdown. Can someone help clarify how these ratios are determined and why they are interpreted this way?

Wouldn't it be easier to just find a way to determine distance from center on opposite ends? Like the total width of a card is 64mm. The distance from 7 line to center is 21.5mm and distance from 10 to center is 17mm. So would center percentage be (21.5-17)/64 = ~7%. In other words it is roughly 7% heavier on the right side If I use same logic for 1 on left and 2 on right, I get 31.5 and 30 (1.5/64) which would give me 2.34% off center, which a lot better than the 10-7.

Would love an ELI5 on all this, and your thoughts on the best method. Thanks all!

CenteringTool.png Example.PNG HowToUse.png Ratio_Guide.png
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fading sigil
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This sounds like an interesting question, although I dont think I can see why either so I cant help