re: PS Preview
re: PS Preview
- Subject: re: PS Preview
- From: Dan Reid <email@hidden>
- Date: Tue, 30 Jan 2007 07:41:55 -0700
- Thread-topic: PS Preview
It¹s kind of funny (not) we are discussing this same topic year after year.
Why? It¹s what I affectionately call the "color management holy grail".
Getting your eyes to adapt from an emissive proof to reflective proof is
very difficult as everyone finds out eventually. The following are some
suggestions to aid in getting a *closer* visual correlation between the
emissive and reflective proofs. It will never be perfect because as this is
subjective.
When is PS Preview you need to use the simulate paper white to correctly
proof the file. Without then you are scaling the printable black to the
black of the monitor and paper white to the white of the monitor. Doesn't it
look nice when that dynamic range scaling is by default engaged?
If your file is already converted then select the same profile to engage
simulate white point to get an absolute colormetric rendering to your
display.
1) Absolutely need to have 1" white border canvas surrounding your image for
your eye to adapt to as the white.
2) Photoshop needs to be set full screen black background with no palettes
to interfere with your eye adapting the to white border.
3) (This is what you have been waiting for!) DON'T use D50 as your light
source for your proofer profile. Yeah, you ain't under D50 bud so get over
it. Measure the light source you will be evaluating the print under and use
that light source data to adapt your proofer ICC profile to this custom
white point. Remember all ICC profiles are built with the grand assumption
that you are under D50 lighting (LAB D50). So depending on how far off your
light source is from D50 will impact your color match.
You see PS Preview using your proofer profile is showing what the colors
look like under D50. Unfortunately, you are not viewing under D50 even if
you have a GTI, Just-Normlicht, or GretagMacbeth booth. These booths are
really F8 illuminants masquerading as D50. Just measure any of them and
compare to D50 and you might be surprised at the difference. Doesn't mean
these booths are bad by any means but if you are really **** about this then
you need to adapt the spectral measurements to the light source you are
viewing the prints under. And before everyone flips out on this concept,
remember we are talking about a proof not the separation or output profile.
Now as for monitor calibration I would not recommend dumbing down your
monitor's contrast range to match print (uh, that's what the PS Preview
does!) Just like any proofer profile, we need a bigger bucket to simulate
the smaller inferior final print conditions. Lastly, you will NEVER be able
to calibrate a display to D50 although a correlated temperature of 5000K is
possible. You can't change the spectral response of CRT or LCD to match D50,
sorry ain't possible. Measuring the light source used to evaluate your
proofs you can get a correlated white point temperature to use but that's
akin to a letter grade in school (I always hated GPA). This is why many of
the profiling products allow adjustment of the monitor's white point tuning
for a closer visual correlation. Note this happens in the monitor profiling
software and NOT on the monitor hardware.
As you can tell there is a lot going on here to make a successful
correlation between emissive and reflective proofs. Not for the faint of
heart and understandable why many are frustrated with the disparity on
screen. Like usual, your mileage ( tolerance ) will vary widely from
individual to individual. Good luck, and good night.
PS. You folks measuring LAB delta E just remember that all the Delta E
calculations are making the grand assumption you are viewing prints under
D50. So the data may indicate a good (perfect) match but your eyes say
otherwise, this is usually the culprit. A better approach would be measure
spectral and apply your light source measurement to the spectral data to
compare against the same spectra with D50 applied. This might shed some
light on why things look a certain way under your light source. :)
--
Dan B. Reid
RPimaging
Color Management Products and Training for Print, Internet, and Motion
Graphics
http://www.rpimaging.com | Toll Free: (866) RGB-CMYK
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