[svlug] Monitor calibration, photo processing

John Conover conover at rahul.net
Mon Apr 7 14:49:44 PDT 2008


John Conover writes:
> Larry Colen writes:
> > On Mon, Apr 07, 2008 at 12:33:05PM -0700, Florin Andrei wrote:
> > # Larry Colen wrote:
> > # > I finally got a few minutes to try to calibrate the gamma on my
> > # > monitors. I found a program called Monica that seems to do what I
> > # > need, via some links John Conover sent (thanks John). 
> > # > 
> > # > The page for monica is at:
> > # > http://www.pcbypaul.com/software/monica.html
> > # 
> > # Assuming I use it to calibrate the monitor, how would the results 
> > # compare with what I obtain by using the gamma correction wizard provided 
> > # with the NVidia drivers on Windows? (Display Optimization Wizard / 
> > # Optimize Gamma / drag the RGB sliders)
> > # It seems like Monica and the NVidia wizard work almost exactly the same.
> > 
> > I haven't tried booting into Windows to use the NVidia wizard, but I
> > expect that it'll get you some gamma value (like .61) that you would
> > feed to xgamma in some sort of startup script.
> > 
> > On my Fedora box, there isn't a .xinitrc to put the call
> > xgamma .61
> > in. 
> > 
> 
> Hi Larry. Maybe and ~/.xsession?
>

After you get xgamma set, shoot a flick of the screen of the gamma
picture. Take the camera jpg and display it against the original gamma
picture, side-by-side on the moinitor screen to get the system wide
camera input to your monitor. (Might have to didle with the shutter
speed to get a flick without a scan bar on it if its a CRT.)

There will be very slight differences, (there always are,) but they
should be very close.

Then print the camera jpg on your printer, and find out what gamma to
use on the printer, (in Gimp, or PhotoShop, etc.) Then the camera and
your printer aligned system wide, though the monitor display.

That way, what you shoot is what you get on your printer. (The gamma
on the HPs is about 2.2, Epson cmyk's about 1.6, and Apple/Laserjet,
about 1.8, from what I've seen.)

     John

-- 

John Conover, conover at rahul.net, http://www.johncon.com/




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