[Gimp-user] Re: Monitor for Gimp

2004-03-29 Thread GSR - FR
[This is personal experience from amateur, so direct instead of list
reply]

[EMAIL PROTECTED] (2004-03-28 at 1438.12 -0500):
 Is there a monitor at a reasonable cost, a few hundreds of 
 dollars, that allows for adjustment of gamma? Bearing in 

Doubt so, but you can get the adjustment via relatively supported
videocard (I tried Matrox and ATI with Xfree86 drivers) and tools to
tweak the LUT, look up table (xgamma, ie). Speaking about monitors,
you can get CRTs with good quality for that price. They should let you
select colour temperatures and come with their own profile.

Check the pro range of known brands, probably the 19 and 21 inches
sizes only. Three years ago 17 inches was pro too, now that size is
crowded by TFTs (*1). Then download all the manuals you can find to inspect
what they do. Matching will not be perfect, but you will be safer than
with a go figure how it behaves monitor.

For the past six or seven years I used Hitachi, CM641ET and CM643ET,
both 17 inches (both same specs, they just changed the name, I think),
nice quality. But they are leaving that market and going for TFTs
now. So some months ago I got a Philips 109P40 for a bit more than 300
euros.

It comes with 9300K, 6500K, 5500K and sRGB presets, allows mid-high
resolutions at high refreshes (using 1280*960 at 100Hz at this
moment), and the target market is CAD and DTP. It even has an extra
input, just in case you need to plug two computers or you have a
workstation that uses BNC instead of the typical 15 pin D-Sub. I
wanted it a bit for colour quality, and a lot for the flicker free
with reasonable resolution, my usage is non pro, but is impossible to
get a monitor in which flicker free is not tied to nice tube and lots
of controls.

I also checked Hitachi, but they are going out of the CRT field as I
said, NEC (fine), Mitsubishi (fine), Sony (expensive), Eizo (also
expensive), Iiyama (fine), LaCie (they rebrand others, and add some
things). Most of them are basicaly *tron tubes (Trinitron, Diamontron,
Whatevertron or just this monitor uses aperture grille tube). The
two lines that cross the screen are weird the first days, or when you
try to concentrate in that area of screen. The *tron mask was also a
bit strange for me, cos I was used to the Hitachi tubes, which
provided really sharp images with their own technology.

If you can go to the shops and see the monitors working, that would be
the best. I did that for the Hitachis, and I was really happy with
them. With the Philips it was a different story, now shops go for
flashy TFTs so I was unable to check a real model in shops around
here, and had to buy by phone a bit blindly.

Good luck shopping. :]

*1: Personally I only like them for pure text processing due the lack
of flicker and reduced weight, but hate them for weird 1280*1024
resolution some have, lack of high resolutions (funny to find
1600*1200 or 1400*1050 in laptops but rarely in desktop TFTs, LaCie
has one but expensive) and the varying colour response. I still have
to find someone that can prove the gamut is above CRTs, last I read
was that a medical targeted monitor with a price over a thousand was
approaching 90% of NTSC range, if my memory does not fail. The mag
company I know go with CRTs, and I agree with the friend I have there:
not yet, maybe in the future, if colour is more important than space,
buy CRTs.

GSR
 
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[Gimp-user] Re: Monitor for Gimp

2004-03-29 Thread GSR - FR
[EMAIL PROTECTED] (2004-03-29 at 1424.48 +0200):
 [This is personal experience from amateur, so direct instead of list
 reply]

Obviously not. Never start a reply while sleepy and never hit send
before checking the field one more time. *hit wall with head*

GSR
 
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Re : [Gimp-user] Monitor for Gimp

2004-03-29 Thread Jean-Luc Coulon (f5ibh)
Le 29.03.2004 01:46, John Culleton a écrit :
On Sunday 28 March 2004 04:15 pm, Jean-Luc wrote:
On Sun, Mar 28, 2004 at 02:38:12PM -0500, John Culleton
wrote:
The best is to adjust the gamma within the Xfree
software. There is an application called kgamma and a
plugin for gkrellm to do such an adjustement.
KGamma for some reason was not included on my LInux
Slackware 9.1 system so I downloaded the Kgraphics 3.2
package and am compiling it as I write this.
I had no luck with LProf and sent an inquiry to the authors.
Whenever I tried to load a file it just quit suddenly with
no error message.

Is Gamma adjustable on monitors less than $1,000 US?
In fact, you don't adjust the gamma of the monitor, you tune the window  
manager, the whole xfree or the application to match the gamma of your  
monitor. The gamma of the monitor is the transfer function of the  
electron beams of your monitor. It describes the non-linear relation  
between the pixel values and the monitor luminance.

Luminance = (pixelvalue/255)^^gamma

As an example, you will find attached what is such a transfer function  
for several value of gamma.

General, the commonly admited value of gamma for PC is 2.2, the value  
for a MAC is 1.8 and a liear transfer function will gives 1.

There is also an other setting you have to take care of: it is the  
colour temperature of your display. There is for most the display the  
choice of different colour temperature. The default value is 9500K  
which gives very cold colours (too much blue). This is perfect for  
office work. For digital photo processing a colour temperature of 6500K  
if available is more suitable.

--
John Culleton


--
Regards
- Jean-Lucattachment: gamma.png

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Re: [Gimp-user] Re: Monitor for Gimp

2004-03-29 Thread Jakub Steiner
V Po 29. 03. 2004 v 16:27 +0200 pe Sven Neumann:

 Please excuse my ignorance, I am trying to understand what's really
 needed for professional image manipulation and so far I understood
 that global gamma correction is not desirable.

As a metatheme author I think it is very desirable to have a global
gamma correction. Same reasons apply to the widget theme as it does for
displaying images.

Great example is the Industrial gtk theme that uses a very light gray
that on some system simply looks white. Apple has a nice system-wide
calibration in OSX called ColorSync I believe.

cheers

-- 
Jakub Steiner [EMAIL PROTECTED]

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