Datacolor User to User Support Group.

Thanks David (and Paul). Will here.

My original post (1705) got all this going and has unfortunately been
lost in the shuffle I am afraid with the paper white ref riding to the
top of the conversation. Relative to that I have a few comments and
questions.

I do habitually click the Paper white reference, not because of
knowledge of exactly what it does, but because it makes sense to me
since it is taken from having read the "white" of the paper and this
would be a logical addition to the profile.

Also, as I said in the original post, I use 5000K on my monitor
calibration and a 5000K light so I am matched, though not at the temp
you suggest. Does this matter? Matched light with a calibration at
5000 versus 6500? If it does, I have not been successful in finding
this array of lights you spoke of. Lots of "daylight spectrum", but
the ones I found were 5000-6000K. On the GE sight all I could find at
6500 were normal fluorescents. Can you suggest a place to find compact
fluorescent bulbs or desktop/floor lamps that are 6500K?

Third, I was aware of the slider change as my post says. I am also
aware that the green/yellow shift is very noticeable after taking 967
readings to create the profile. Now that I am aware that I can expect
up to 13 blue and 6 magenta to balance the color it will be easier to
make profiles. It does seem bizarre and unexplainable to me though,
that such a complete color reading from colors printed by my own
printer and viewed on my very good, calibrated monitor could be
calculated in a way that would be so far off as to have what is
visually an extreme color cast. Can you explain this to me? Have I
done something wrong?

Fourth, relative to my Lacie lcd monitor, and the eizo I tried, they
do "look" more blue/magenta than my old Samsung calibrated to the same
color temp with the same software/colormeter. This is why I was
wondering if there was some potential for interpretation of neutral
color? On these high-end monitors, the grays are definitely evener
from white to black with no color casts in any area of the gray scale,
and though they do have a bluer/more magenta "feeling" they look
decidedly gray to me. Can this be a part of this issue of green/yellow
cast?

On your suggestion, I printed the gray test print from PFP through my
new profile and the largish gray panel next to the black one, just
left of the word Colorvision measures L=52.2, a=.32, b=1.30. I have no
knowledge of LAB. Can you interpret this? Or can you point me to a
good and simple tutorial that describes how to use LAB measurements? I
am wondering if this could be used as a pointer to adjusting profiles
accurately? Can it tell you whether to be looking at red rather than
magenta for example? or green versus yellow?

Finally, can you give me any insight into the dual monitor question I
asked in post 1705. I'm using a Mac and have the menus and tools on
one monitor that  I assume the Mac and Photoshop see as the primary
monitor since this is the desktop monitor. I like having my good
monitor completely empty except for the photo, therefore I put all the
menus on the other one. So the photo viewing monitor is what the Mac
considers the secondary monitor. The question is, does Photoshop/the
Mac "know" which monitor the photo is on as it initiates color managed
workflow? As I said in that post, to be safe, I have chosen the
profile of my photo viewing monitor in the preference of the monitor
that has the menus and desktop just in case the Mac needs that for
proper color management. This is tedious though and makes profiling
the tools monitor sort of irrelevant. Thus the question. Can you help?

Thanks very much,

Will




--- In colorvision_group@yahoogroups.com, David Miller <dm2363@...> wrote:
>
> >Hey Paul,
> >
> >Thanks for the encouragement. I am glad to hear that you arrived at
> >good profiles and found that all your gear was OK. With the variables
> >of a new (and expensive!) monitor setup, and a new iteration of the
> >program, it got confusing for me. I wonder why we are experiencing
> >roughly the same color shift issues, manageable as they may be with a
> >relatively consistent range of adjustments. On the other hand, though
> >you have found that different levels of Magenta and Blue will put
> >things right, the need for up to 5 Magenta and 12 Blue indicates what
> >is to me a lot of Green/Yellow to compensate for. The down side of
> >this is it can present the need for a lot of testing, which is what I
> >bought PFP to avoid. I wonder if it is that Eizo and Lacie have
> >similar methods of describing and arriving at neutral colors, and that
> >these are different from the Colorvision models used in developing
> >PrinFixPro? I look forward to a response from David (s) to get his
> >take on this color shift issue and on my questions about using dual
> >monitors on a Mac in my original post.
> >
> 
> A couple of quick comments:
> 
> Calibrate your displays for D65, gamma 2.2. And when you view prints,
> use a "daylight spectrum" light bulb, with a color temperature of 6500K,
> to view them with. (Plenty of floor/table lamps sold this way, and you
> can also get bulbs from GE, for instance, if you look through the
product
> list on their web site).
> 
> In PFP 2.0, we changed the slider range adjustments, so they're "half as
> strong" as they were in the original 1.0 and 1.1.1 versions.
> 
> So an adjustment of 5 magenta in 2.0 is the equivalent of 2.5 in the
older
> versions; and 12 Blue is the equivalent of 6 in the older versions;
these
> are both very small adjustments; the numbers aren't as "big" as they
seem
> to be.
> 
> In terms of "neutral", what you can do to check the actual neutrality of
> printing through your profiles, in terms of how the spectro sees color,
> is this: after you've built a profile with all sliders at 0, (and
this should
> be a profile created from both a color target and the extended grays
> supplement), take a grayscale image (for example, the B&W test image we
> provide) and print it through the profile.
> 
> Then use the Measure tool in PFP and measure the grays that you've
printed.
> (For example, one of the solid gray patches at or near 50% gray).
> 
> See what Lab values the spectro reads. A "perfectly" neutral gray
will have
> a Lab where a = b = 0.0
> 
> That kind of ultimate perfection isn't going to happen, but you
should get
> a and b values that are close to 0. Regardless of what things look like
> to your eyes, that's what "neutral" really measures as.
> 
> Best regards,
> 
> -- 
> David Miller
> Senior Software Developer, Digital Color Solutions
> ColorVision
>