images in cross-platform stacks

[Martin Baxter]

Richard Gaskin wrote:
> Martin Baxter wrote:
>> Does it not also have to do with being able to discern subtleties of 
>> shadow detail on-screen? Uncorrected CRT Gamma (as per Win / Nix / 
>> Television) gives a very non-linear display and tends to compress the 
>> bottom 20% to black.
> 
> It's a tradeoff:  the Apple gamma may give more detail among darker 
> colors, but at the loss of detail among lighter ones.  The default gamma 
> for Macs is so light that the whole thing looks washed out to me; the 
> first thing I do when I get a new Mac is make it readable by increasing 
> the gamma.
> 
> We can't rule out the possibility that the entire world outside of 1 
> Infinite Loop may not be wrong.
> 

Ah, but, I would say the point is that the lighter values are 
over-represented in the first place, gamma correction just helps to give 
the shadows a bit more of a look-in.

When I used to teach Photoshop I would sometimes have students bring in 
images they'd made on their PC's at home. They would be disgruntled 
because their images looked all washed-out on the Mac.

Then I would have them examine the histogram of their image data, which 
would always turn out to have no pixel values lower than about 35,35,35 
and sometimes worse than that, nothing lower than 40 or 50. Why in that 
case should the computer display any black?

Colour-management is supposed to get around these issues as far as 
possible, and it does a great job when set up correctly. But in the 
wider world where systems are generally uncalibrated, uncorrected, badly 
adjusted, badly-sited, old, cheap, mobile and so on, it's rather 
irrelevant. None of my equipment is what I'd consider calibrated in 
fact, how about yours?

As for Apple the company, there is plenty to criticise, no argument from 
me on that. However, when it comes to gamma, both Mac and PC users are 
free to set whatever gamma they like, if they care. I suspect that 
Apple's print industry customers do prefer their system with a bit of 
gamma correction. Web site makers like yours truly just have to be aware 
of the real world and compromise as best we can IMO.

Still I can talk big, but here I am sitting at a Win XP system with the 
gamma set to 1.0 (linear) whatever that actually means. And it looks OK 
to me. Maybe I need eye surgery. (or soon will) ;-)

Martin Baxter