Colour question again ( sorry )

Fisrtly, let me thank you guys for taking the time answering my posts. I personally think it's impossible to understand colour management over one weekend and as the time passes by I feel that I know more and more about this scaring and intimidating topic of colour management.

Here is a couple of questions that I thought of the other day. I think the answer to the 1st one is 'no' but I need your reassurance

1. I use a normal gamut monitor(HP ZR24w) will I see any difference/ benefit working in colour spaces other than sRGB. I think as my monitor cannot display colours outside the sRGB gamut, I won't see any difference on my monitor switching between those colour spaces, right?So apart from future proofing my images should they invent a monitor capable of displaying double the ProPhotoRGB colour space, there is no reason to work in a colour space other than sRGB if you use a normal gamut monitor like mine.

2. Then, the next question is this. If I work on a wide gamut display in a colour space other than sRGB and than save for web(sRGB) what will happen with the colours that are outside the sRGB gamut. Will photoshop 'invent' them somehow or will they be replaced with the nearest one. If so, then in almost all cases when working in let's say AdobeRGB and than converting to sRGB will result in an image that slighlt different to the original, correct?

3.I know it's been explaind here before but I cannot seem to find that particular post here. Can someone run this through me again. What do the asterisk ' * ' signs mean. I know that depending where ther are it warns you about the colour profile mismatches, right? Why is it that when I start with an images there is no * and then as soon as I duplicate the layer an asterisk comes on?

4. And finally, when you save for web a window comes up divided into four parts. These are 'Original', 'Optimised', '2-up', '4-up'. What is the purpose of those and what do they do?

I know there are a few questions here so I hope it all makes sense and I will find some time helping me to understand CM even better.

Really appreciate your help.

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kjonnnn wrote in post #13177950
3. It means the file has been changed and not saved since you opened it.

Thanks kjonnnn. And what about other positions of asterisk?

1. Just because you can't see colors it doesn't mean they're not there. I use a cheap Samsung LCD and it matches my prints just fine, i'm a wedding pro. Your output device (printer) is more important than your view of the image, unless you're doing critical color matching - which is different from basic color correction or making a nice looking image.
2. Related to #1. Wide gamut displays sound like a waste of money for most people, to me. If the colors in your document don't fit inside your output color space they're rendered to something that will fit with something called something like a rendering intent - I forget the details.
4. Shows you the image with varying levels of compression.

Get and read this book.

Question #2 first. When you convert from a larger space to a smaller one something has to be done about those colors that are outside the small space. The method of dealing with them is called a Rendering Intent and there are two of them that photographers use, Perceptual and Relative Colorimetric. Imagine a team of football players sitting on a bench. Now we move them to a shorter bench and the guy at the end has no place to sit. He can do two things - he can yell, "Hey you guys, move over," and several player scrunch together until there is room for him to sit at the end. That's Perceptual Rendering. Or he can sit on the lap of the player already sitting at the end. That's Colorimetric Rendering. In Perceptual the out-of-gamut colors are changed to the closest in-gamut colors and several nearby colors are changed also, compressing them to make room. In Relative Colorimetric the OOG colors all become the closest in-gamut color but other in-gamut colors don't change, so if in the wide space you had Red 1, Red 2, Red 3 and Red 4, of which only Red 1 is also in the narrow space, all the reds are now Red 1. Fine gradations and details are lost. Conversions from ProPhoto RGB or Adobe RGB to sRGB are always R. C., conversions to a device (monitor or printer) space can be either if the profile allows for it.

So to answer #1., if the image is in a space larger than the monitor's space, you may see inaccuracies in colors that are close to the limits, but those will be a small percentage of the millions of colors in the image. So editing in a wide space won't offer any direct advantage, but if you print with a good quality inkjet its gamut will very likely be wider than your "normal" monitor.

tzalman wrote in post #13178296
. Imagine a team of football players sitting on a bench. Now we move them to a shorter bench and the guy at the end has no place to sit. He can do two things - he can yell, "Hey you guys, move over," and several player scrunch together until there is room for him to sit at the end. That's Perceptual Rendering. Or he can sit on the lap of the player already sitting at the end. That's Colorimetric Rendering.

Thanks tzalman! That must be by far the best way to explain the diffrence between those to renderings! Brilliant!

Conversion from AdobeRGB to sRGB in Photoshop are always colorimetric.

Save for web: http://www.getcolorman​aged.com/color-management/saveforweb/

On the asteriks:

Kjonnnn, tim, tzalman, Rene, thank you very much for explaing all the above.
I will definately return with more questions soon.