# Quick reflection density question

• 06-12-2012, 09:58 AM
Michael R 1974
Quick reflection density question
Hi - what is the reflection density of middle grey/zone V. I guess let's assume 18% grey for middle grey for now.

Thanks
• 06-12-2012, 10:04 AM
Bill Burk
Around 0.75
• 06-12-2012, 10:17 AM
Michael R 1974
Just to be clear - you're talking about reflection (paper) density, not transmission (negative) density, right?

Thanks
• 06-12-2012, 10:21 AM
Bill Burk
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.

• 06-12-2012, 10:21 AM
Chan Tran
Quote:

Originally Posted by Michael R 1974
Hi - what is the reflection density of middle grey/zone V. I guess let's assume 18% grey for middle grey for now.

Thanks

If it's 18% reflectance then the density is .75
• 06-12-2012, 10:33 AM
Michael R 1974
Thanks for the help, guys.

Michael
• 06-12-2012, 01:25 PM
Helen B
For reference the formula is

Reflection Density = log10(incident/reflected)

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

Best,
Helen