Oh yeah, sorry about forgetting what you said a few months ago concerning
that.  Thanks.

Does this mean only a LCD is liable to be okay for setting both display and
assumed gamma to 1.0?  Or is that okay for a CRT too?  I take it the answer
is no.

Bob H.

"Kari Kivisalo" <ray### [at] engineercom> wrote in message
news:3BB0662D.236C2598@engineer.com...
> "Bob H." wrote:
> >
> > If I set that to 2.3 though, which is what I get for the LCD screen
>
> LCD and gamma don't mix. Gamma correction is for CRT only.
>
> The response curve of non compensated LCD displays is totally
> different from CRT response and trying to measure or apply
> gamma with that hardware won't do much good.
>
> I know there are TFT displays that emulate sRGB CRT and those
> are hard wired to gamma 2.2. They can be used for graphics work
> but the LCD displays I have seen have been non compensated
> and unsuitable for editing graphics.
>
> So, if the manual that came with the hardware doesn't mention
> anything about sRGB, CRT or gamma emulation forget gamma.
>
> Quick search produced this review about LCD projectors. What is
> said here applies also to LCD displays. In short, LCD displays
> are problematic.
>
> From http://www.zdnet.co.uk/pcmag/labs/2000/04/projectors/21.html
> ----
> Gamma is a critical parameter for any display product because it
> determines how accurately tonal values are reproduced. Although
> this might not be so important for high-contrast business
> graphics, it's important for the reproduction of natural
> images--high-quality images of fine art, for example. Displays
> with response curves that follow a power curve
> (but with the 'wrong' exponent) can be corrected to the desired
> curve. However, some display products exhibit black and white
> compression, resulting in an S-shaped curve. Unless this can be
> removed by manipulation of the brightness and contrast controls,
> images displayed by these products can't be improved purely by
> simple gamma correction.
>
> The gamma characteristics for many of these projectors show large
> deviations from the ideal, and the controls that relate to gamma
> contrast and brightness were difficult to set. In this review, the
> Philips Hopper XG10 and, to a lesser extent, the Toshiba TLP651E
> both have S-shaped gamma curves.
> ----
>
>
>
> _____________
> Kari Kivisalo

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