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Re: filmscanners: Setting screen gamma problem



Me too I struggled a lot with calibrating my Viewsonic PF815 22' monitor.
I used Adobe Gamma on the Gamma-space 2.2 monitor calibration chart made by
Timo Autiokari on www.aim-dtp.net. and
http://www.aim-dtp.net/aim/evaluation/gamma_space/index.htm. He made also
many other gamma charts.  I downloaded the 2.2 chart and placed it as the
desktop wall. Withy Adobe Gamma I managed to get a quiet good calibrated
monitor on all the grey values from deep black to high white. When looking
at the Yellow Rose from Lawrence W.Smith in PS6.01 I can see clearly the
subtle details in the leave and the beautifull colors in the rose. It
indicates me that my calibrtion is correct.
I suggest you try this too and see what it gives...

Jean-Pierre Verbeke


----- Original Message -----
From: "laurie" <laurie@advancenet.net>
To: <filmscanners@halftone.co.uk>
Sent: Thursday, June 28, 2001 5:57 PM
Subject: RE: filmscanners: Setting screen gamma problem


> I did nto read the post thoroughly; but I would suggest that some of the
> difference may very well be that your monitor is set at a different color
> tempurature than those that you looked at which would effect the rendering
> of the gamma setting.  Moreover, you may not have hour monitor's
brightness
> and contrast settings set at the same levels as was the case on the other
> monitors.  Gamma settings is only one component in monitor calibration;
> monitor calibration is not the same thing as color management but merely
the
> first step in color management.  For WYSIWYG to work across multiple
> systems, all the systems have to be calibrated to the same standard of
color
> temperature, gamma, white point and black point, brightness and contrast.
>
> Not to be funny; but how sure are you fo the acccurracy of your step
wedge?
> Most commercial step wedges are created using precision measurement
> instruments and printed to precisely measurable standards.  Is it possible
> that you personnally created step wedge may be out of gamut at the dark
end
> with respect to your monitor?  Is it possible that your web sit files
might
> be tagged with profiles that have small or inapproriate working color
spaces
> so that those receiving the image get images that their systems correct to
> the embedded profile?
>
> -----Original Message-----
> From: owner-filmscanners@halftone.co.uk
> [mailto:owner-filmscanners@halftone.co.uk]On Behalf Of Julian Robinson
> Sent: Wednesday, June 27, 2001 7:50 AM
> To: filmscanners@halftone.co.uk
> Subject: filmscanners: Setting screen gamma problem
>
>
> I know this topic is revisited ad nauseum, but I have just discovered that
> what I thought was the Right Thing To Do does not appear to be right at
> all.  On my system,  Adobe Gamma setup seems to be worse than no setup at
> all.   I have cross posted this to Epson7x7, filmscanners, scan and
digital
> silver lists.
>
> This post has become very long, read it if you are interested, but the
> essence of my question is ...
> ******************************************************************
> Please look at my simple greyscale step wedge at
> www.austarmetro.com.au/~julian/stepwedge.htm and tell me if setting this
up
> for equal visual steps is a valid way of setting screen gamma, and does
> *your* monitor show this wedge accurately?
> ******************************************************************
>
> My problem was to make my recently web-published photos look reasonable on
> other people's monitors.  I use PS5.5 and a Sony 400PS monitor.
>
> I thought I had this all sussed, because I had religiously used Adobe
Gamma
> to give me what I assumed would be, maybe not perfect, but at least
> ball-park OK settings.  I then looked at my pubescent website on someone
> else's computer to discover all my deep beautiful saturated colors were
> pale, insignificant and plain ugly.  I checked a couple of other computers
> and while they vary, generally they give the same result.
>
> My conclusion therefore was that for some reason my screen gamma is set to
> make my screen look too dark.  So I checked Adobe Gamma again but it gave
> me the same settings.
>
> I can't afford a proper calibrator at this time, but decided to go back to
> basics on the assumption that a step wedge greyscale from 0,0,0 to
> 255,255,255 should look balanced on my screen and the steps should all be
> visible and roughly the same "brightness difference" between adjacent
steps
> across the scale.  I constructed a simple step wedge of 17 steps (0,0,0;
> 16,16,16; 32,32,32 ...255,255,255) and it looked bad.  The bottom 3  steps
> were all black, which seemed to confirm that my monitor was NOT adjusted
> correctly.
>
> So I tried then to adjust gamma so that my stepwedge looked ok.  The
> problem is that to achieve this, the gamma has to be set so high as to be
> almost off the scale.  This is the same whether I use the slider on Adobe
> Gamma Utility, or a different setting available in my Matrox card
> adjustment software.   In both cases the gamma required to make the step
> wedge look OK is way up the top end of the adjustment.  And of course all
> my wallpapers and in fact all my images now look pale and washed out.
>
> I have since looked at other photo sites to see how they look with my
"new"
> settings, and the situation is still confused.  On some sites their images
> now look washed out, others look OK.  The average would be roughly half
way
> between my Adobe Gamma setting and my Step Wedge setting.
>
> I am now completely confused, but aware that most of us are probably
making
> false assumptions about how other peoples' web photos are meant to
> look.  For example, Lawrence Smith has a critique site whose address was
> posted on a list today -  at http://www.lwsphoto.com/06_25_critique.htm. I
> looked at this rather beautiful photo but didn't like how dark the stem
and
> leaves were, which agreed with a few of the comments posted at the
> site.  But now that I have adjusted to my "Step Wedge gamma" and looked
> again, the photo looks completely different, and the stem and leaves are
> fine.  Which is right?  There is a HUGE difference.
>
> Any answers to my questions welcomed...
>
> -  is my assumption correct that such a stepwedge is a
>     reasonable way to set up screen gamma?
> - why doesn't the setting that this implies agree with the setting
> suggested by
>     Adobe Gamma? There is a HUGE difference.
> - why is the correct gamma setting according to my stepwedge so high,
> nearly off scale?
> - what kind of gamma are most monitors actually aligned to IN PRACTICE?  I
> know about nominal 1.8 and 2.2 for Apple and PCs, but it doesn't seem that
> this bears much relationship to reality?
>
> Julian
>
> Julian Robinson
> in usually sunny, smog free Canberra, Australia
>
>




 




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