Reflection densitometer help needed

  • Thread starter Thread starter KenP
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KenP

My question is this: what sort of reading should I expect from a
standard 18 percent grey card when measuring it with a reflection
densitometer that gives readings in visual density, cyan, magenta and
yellow? My readings don't make a whole lot of sense to me, I get:

V = 0.81D
C = 0.10D
M = 3.01D
Y = 0.37D

Does this make sense? Why aren't cyan (C), magenta (M) and yellow (Y)
all equal? And why does density read 0.81 instead of approx. 0.18?

Thanks for any help,

-KenP
 
KenP said:
My question is this: what sort of reading should I expect from a
standard 18 percent grey card when measuring it with a reflection
densitometer that gives readings in visual density, cyan, magenta and
yellow? My readings don't make a whole lot of sense to me, I get:

V = 0.81D
C = 0.10D
M = 3.01D
Y = 0.37D

Does this make sense? Why aren't cyan (C), magenta (M) and yellow (Y)
all equal? And why does density read 0.81 instead of approx. 0.18?

Thanks for any help,

-KenP
Click to expand...

I agree with you. If you used a kodak grey card its very strange a
3.01 Magenta density reading. It's impossible such high value.
Kodak grey card reflects 18% so visual density should be:
Log (100/18)=.74 but not .18
If your visual density reading is Ok means that your grey card
reflects 15.5% instead of 18%. Maybe your densitometer needs
calibration or your card is not a real 18%
-Francesc
 
I agree with you. If you used a kodak grey card its very strange a
3.01 Magenta density reading. It's impossible such high value.
Kodak grey card reflects 18% so visual density should be:
Log (100/18)=.74 but not .18
If your visual density reading is Ok means that your grey card
reflects 15.5% instead of 18%. Maybe your densitometer needs
calibration or your card is not a real 18%
-Francesc
Click to expand...
Thanks for your reply, I found my problem was as expected, operator
error. The densitometer (a new item for me) was in a mode that
recalled the last dominant color. When set up correctly, the
measurements are all approximately 0.79 as expected. This is a little
high, since in theory it should be about 0.75, but a few others also
appear to be getting readings in the 0.80 area so I don't feel too bad
about it.
 
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