# Quick reflection density question

Discussion in 'Enlarging' started by michael_r, Jun 12, 2012.

1. ### michael_rSubscriber

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Hi - what is the reflection density of middle grey/zone V. I guess let's assume 18% grey for middle grey for now.

Thanks

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Around 0.75

3. ### michael_rSubscriber

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Just to be clear - you're talking about reflection (paper) density, not transmission (negative) density, right?

Thanks

4. ### Bill BurkSubscriber

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Yes, the math is the same I think...

Just to confirm though, I fired up the densitometer and measured the 18% gray card in an old photoguide.

5. ### Chan TranMember

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If it's 18% reflectance then the density is .75

6. ### michael_rSubscriber

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Thanks for the help, guys.

Michael

7. ### Helen BMember

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For reference the formula is

Reflection Density = log10(incident/reflected)

so for 18% it is log10(100/18)

Best,
Helen