Re: Sony Artisan 1.2 Colorspaces Question
Re: Sony Artisan 1.2 Colorspaces Question
- Subject: Re: Sony Artisan 1.2 Colorspaces Question
- From: Roger Breton <email@hidden>
- Date: Tue, 02 Sep 2003 08:31:07 -0400
Hi Rick,
>
1) My first question concerns determining the ideal contrast ratio: 300:1
>
(PrintRGB), 400:1 (PhotoRGB), or 500:1 (FineArtRGB). I
Wow! The SONY Artisan really gives you all these options? Anyone ever
measured those to be more than hot air? What, you take the ratio of the
white point Luminance to the black point Luminance and that gives you the
"Contrast Ratio"? Care to quote some actual, measured Luminance values from
your monitor, Rick?
>
With version 1.1, I was using the 300:1 ratio at D65/g2.2. I am about to
>
embark on a marathon project of separating many RGB graphics to CMYK.
How about taking a sample of the Luminance of some of the coated glossy
stock you intend to print yoour jobs for the sake of comparison? Here's what
I find when I measure some characteriztion target under a 1000W quartz
halogen lamp with a Minolta 1 degree Luminance meter:
350% CMYK 136 Cd/m2
White stock 367 Cd/m2
As you can see, that's not a very big contrast ratio of 2.69! If I measure
under a dimmer light like a Solux 50W 35degree 4700K lamp at 8 feet from the
printed sheet I get:
350% CMYK 2 Cd/m2
White stock 42 Cd/m2
Or a contrast ratio of 21.
>
Naturally, I want optimal fidelity throughout the image, but I would prefer to
>
create a realistic relationship between my shadow values in Photoshop and what
>
I can actually get on press. If I up the contrast ratio to 400-500, will I
>
risk seeing too much shadow detail and the attendant possibility of not
>
opening up my shadows sufficiently compared to the prior 300:1 ratio?
I don't know what to tell you in light of the my measurements above? Anyne
care to throw a different interpretation to my measurements?
>
2) My second question concerns the new capability to calibrate to the natural
>
gamma of the monitor. What are your thoughts about this feature?
Personally, my current thinking is to calibrate as close my monitor as
posible to my usual 5000K target color temperature, using my Mitsu900u
limited color temperature presets, and use whathever chromaticities this
gives me as my 'native white point'. I get as close as 5250K by selecting
5000K on my monitor.
>
I am working in a room with medium ambient light during the day and
>
medium-to-low (more controllable) ambient light at night. Before running too
>
many variant calibrations, I'll wait for a response -- particularly from some
>
of the Artisan 1.2 beta testers. Thanks.
I am not an Artisan beta testers (I'd wish I could afford one of those) but
if I hold my Minolta Illuminance meter CL-100 to my screen and measure the
amount of light falling on it, I get 34 Lux with a CCT of 5959K (x=0.323
y=0.330). I believe the lastest revision of ISO-3664 calls for less than 64
Lux for monitor to print viewing and, preferably, much lower -- at less than
32 Lux (for low Luminance monitor like mine -- 85 Cd/m2 calibrated white
point). It also says that the color temperature of the ambient light should
be approximately the same as the white point of the monitor, so that
chromatic adaptation complications are minimized. That's from page 52,
"Guilines for Choosing the Correct Viewing Conditions for Colour
Publishing", PIRA, 1998 ISBN 1 85802 236 3, Tony Johnson and Marcus
Scott-Taggart.
Any other ideas?
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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