What is the difference between Adobe RGB and sRGB and related questions.

Hi, Asher,

Asher Kelman said:

However it still emits some radiation . . .

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Well, I would hope.

Best regards,

Doug

Doug,

The problem is that one accumulates the low levels. The lower the energy the worse effect it has on your cornea! Most of the Kv energy is depositied in the first 0.5mm! So one doesn't want to be spending 8 hours every day close to a CRT if one can just as well use an LCD monitor.

Asher

Hi, Asher,

Asher Kelman said:

The problem is that one accumulates the low levels. . .

Click to expand...

I was speaking of visible radiation!

Best regards,

Doug

Bart_van_der_Wolf said:

A bona fide tri-stimulus output is almost a bit of a contradiction in terms, wouldn't you agree

?

Besides, the Sigma implementation of the Foveon sensor technology lacks the filtration needed for a perceptually accurate spectral reproduction.

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Doug_Kerr said:

How's that?

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Not sure which part of my post you a referring to, but bonafide (reliable, trustworthy) is not what I would label tri-stimulus output with, due to Metamerism or Color Inconsitency effects and possible mismatch with the color matching functions of human vision (which amongst others also shifts with luminance level). Full spectrum is bona fide, but also the Foveon uses a band separation (a function of silicon penetration depth) which by the way is not as exact as they suggest.

That mismatch is exactly one of the issues which is e.g. also noted by Foveon in the following document (page 4, Additional filters to shape overall response). The Sigma incarnations of the technology lack the filtration needed for an optimal match with the human vision Color matching fnctions, because they wanted to retain sensitivity (and reduce cost).

Bart

Asher Kelman said:

So one doesn't want to be spending 8 hours every day close to a CRT if one can just as well use an LCD monitor.

Asher

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From this site (couldn't find the one I was looking for, but it amounts to the same):
"The total ionizing radiation of all wavelengths from the use of a VDT eight hours daily represents a very small portion of the radiation we receive from other consumer products, such as ceramics, combustion of natural gas and fossil fuels. In fact, the ionizing radiation a person absorbs from the rocks, masonry and construction materials in many buildings is generally orders of magnitude greater than any emissions from a VDT"

It's not like putting your head inside a microwave...

René Damkot said:

From this site (couldn't find the one I was looking for, but it amounts to the same):
"The total ionizing radiation of all wavelengths from the use of a VDT eight hours daily represents a very small portion of the radiation we receive from other consumer products, such as ceramics, combustion of natural gas and fossil fuels. In fact, the ionizing radiation a person absorbs from the rocks, masonry and construction materials in many buildings is generally orders of magnitude greater than any emissions from a VDT"

It's not like putting your head inside a microwave...

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Hi René,

Yes, what you have quoted is grossly true. However, that refers to the whole body and not the eyes.

With a CRT, because of the inverse square law, just looking at the CRT from 10" instead of 20" increases 4-fold the radiation dose to the face. The very lowest energy radiation is stopped by the glass and the air. The rest Kv radiation is mostly absorbed in the superficial skin.

Now remember that we have already exposed our faces to more solar radiation than the rest of our bodies. The consequences on the skin is of a 50 year old is obvious when one looks at the breast or trunk areas which have skin that often appears 30 years younger!

I see no reason to add 8 hours of low energy ionizing radiations to already solar-damaged skin and corneas. Yes, we get radiated from the steel in buildings and the potassium in people's bodies in a move theater, but why add to that? If you feel bottled water might be healthier, an LCD might too!

How harmful is CRT radiation to you? I don't know. After all much might be absorbed in the dead keratinized superficial skin. However, who knows what DNA damage you already have. Frankly, I prefer to go with perfectly usable LCD monitors.

Would I be frightened about using a CRT monitor? Certainly not. It's just a matter of choice!

Asher

Hi, Bart,

Bart_van_der_Wolf said:

Not sure which part of my post you a referring to, but bonafide (reliable, trustworthy) is not what I would label tri-stimulus output with

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I was relying on definition 2 from The American Heritage Dictionary: Authentic; genuine:

I should probably have said true or real.

Thanks.

Best regards,

Doug

People, looking at chromaticity dyagram, think that Adobe 1998 has a big advantage in greens. This is a general misconception. CIE_xy space is not perceptually uniform.
When the two gamuts are compared using the CIE_u'v' reference space, better representing the human perception, the advantage in greens becomes less apparent. Adobe RGB 1998 has similar advantages in both the cyans and greens.

There is another difference between sRGB and any other color space I know: the gamma correction.
sRGB uses a sophisticated curve, starting with a linear slope. This result in a better detail visibility in dark tones.

Then view the 3D map in LAB which is (pretty much) preceptually uniform. ColorThink will do this.

As for sRGB, it doesn't have a gamma curve since as you point out, there is a small adjustment in the curve in the shadows. It has a Tone Response Curve. Note that IF you ever use the Simplified sRGB profile available in some applications, its called simplified because it doesn't have this TRC but rather a true 2.2 gamma encoding.