Digital BW, The Print

I have borrowed a Macbeth TR524 CMYK densitometer, but I'm having
trouble trying to understand the values it reports in terms of color
shown in Photoshop. I'm trying to quantify the near-neutral values of
my inksets on Kayenta, but the density numbers that the 524 puts out
don't look anything like the various Color Picker numbers, for
example, my paper white reads as: C= -4.63, M= -4.79, Y = -4.54 and K=
-4.71. How can I use those values to plug something into the Color
Picker that makes sense?

CMYK numbers in the Color Picker must be positive values of no more
than 2 digit whole numbers, so the best I could come up with is to set
Y = 0 and put in the others as rounded-off percents: C = 1, M = 3, Y =
0 and K = 2 which gives me a reasonable-looking white of L = 95, a =
2, b = -2 or RGB = 241, 238, 243.

It is reasonable-looking, but is it reasonable?

I have the same kind of problem with the ink tones: if I subtract the
ink density readings from the paper white readings to get positive
decimal values and convert them to % CMYKs in Photoshop's Color
Picker, the tones look reasonable, but am I just screwing-around in a
color never-never land?

Thanks for all your help,

Frank

What, then,  *do* the values represent when I use the densitometer with 
the C, M & Y filters (?) rotated into position? Have the manufacturers 
been duping users into thinking that the measurements mean something? Is 
the K density value also without relationship to the K in CMYK?

Bruce Lindbloom's "Companding Calculator" alleges a relationship between 
the values, although not in the range of the Macbeth's output, what does 
that mean?

Yours truly puzzled,

Frank

_________________________________________________________
There is no relationship between density values and CMYK color values.
Densitometers don't read color, then just read log density. CMYK values 
are not
density related, and are color based. You are trying to cut down a tree 
with a
sparkplug wrench.

C. David Tobie
Product Technology Manager
ColorVision Business Division
DataColor Inc.
CDTobie@colorvision .com <mailto:CDTobie%40colorvision.com>
www.colorvision. com