On 29/09/2010 4:58 p.m., Bruce Sinclair wrote:
> In article<i7u10c$gah$>, Me<> wrote:
>> On 29/09/2010 12:52 p.m., victor wrote:
>>> On 29/09/2010 12:15 p.m., Dave Doe wrote:
> (snip)
>>> These days if you are a graphic artist it is most likely that your
>>> output is going to be viewed on an LCD screen, hardly anyone is going to
>>> see it on a CRT screen and neither is more representative of a printing
>>> or projection process.
>>>
>> There's certainly a load of potential issues with "wide gamut" displays,
>> colourspace across editors/viewers, lossy colourspace conversion, and
>> (more) limited gamut of other output devices.
>> But if your monitor is sRGB (or able to be set so) and calibrated
>> correctly, your printer capable of printing most of sRGB colourspace,
>> and you use Photoshop gamut warning, soft proof, including "simulate -
>> paper white", you can get pretty good print:screen matches without too
>> much trouble.
>> Beyond that, a can of worms begins to unravel, not helped by some very
>> spurious marketing claims.
>
> But most screens are RGB aren't they ? ... and most printers cmy(k) ? ...
> best of luck transposing between those spaces.
They're RGB in terms of using red green and blue pixels, but there are
some displays which also add yellow pixels (whether it's more than a
marketing gimmick, I don't know)
"s"RGB and "Adobe"RGB are colour spaces, defined here:
http://en.wikipedia.org/wiki/List_of...and_their_uses
Digital image files can be mapped in different colour-space, usually
tagged (metadata) so that "colour space aware" applications can render
them correctly, but the default is sRGB (colour aware applications
should default to sRGB encoding if the image file is untagged). Some
web browsers are colour-space aware, Safari (enabled by default?),
Firefox (disabled by default), possibly others. But it's a bad idea in
general to use other than sRGB for the web, as the way images on your
pages are rendered is going to be different depending on which web
browser people use. AdobeRGB images look unsaturated and flat when
viewed in an application that's not colour aware and "assumes" sRGB.
>
> <thinks --- was there *ever* an RGB printer ? I suspect yes ... but my
> memory is not good enough to remember it/them.
--->
>
I doubt there was. With "subtractive" colour blending using R,G, &B,
the most obvious problem is yellow - with "additive" colour blending,
that's red and green mixed, but if you mix red and green paint, the
result is brown. Full saturation intermediate colours aren't achievable
with "subtractive" blending, the blends are "dirty".
To increase gamut and get around this a bit, some printing processes use
more than CMY(&K), sometimes adding intermediate primary colours, red
("yellower" than magenta) orange ("redder" than yellow),
green("yellower" than cyan) or blue ("redder" than cyan) etc.
If you make a colour chart image of all 16 million or so RGB colours,
rendered in adobe RGB, then view the chart in Photoshop with "Gamut
Warning" toggled on, and an ICC printer profile loaded for any standard
printer, then it's apparent that quite a large area of the chart cannot
be printed accurately for colour. You can also usually see peaks where
saturated colours can be reproduced corresponding the the primary
colours of the inks. But the other side to this is that in nature,
apart from flowers, most of what we see usually falls within sRGB - it's
pretty good - sRGB is fine for photography (IMO - but many will not
agree with me on that) But for graphic artists who want to use the full
and widest colour spectrum, it's not enough, so we now can get wide
gamut displays, can view wide gamut colourspace on screen, and the
marketing boys have found a new "feature" to sell stuff to the average
punter who doesn't know that it's a can of worms.