Without seeing the full context of the post in question, let's just say it doesn't sound like it washes.
A 24 bit document in sRGB and a 24 bit document in Adobe RGB have the same encoding. The author may believe that with a smaller color gamut (sRGB), there are more bits to define 'colors' in a smaller gamut than a larger gamut (AdobeRGB)?
A 24 bit image in either sRGB or Adobe RGB (1998) of a gray card will have less colors than an image of a colorful field of flowers. Scene gamut should not be ignored! Gamut and encoding of data should not be ignored! We can talk about color encoding where the math results in billions of color despite the number of colors we can see are nothing approaching this value.
If I take a Granger Rainbow I built in Lab, high bit, convert one to sRGB and one to sRGB
FROM Adobe RGB (1998) in Photoshop, using V2 profiles and no dither, they both have the same number of unique colors according to ColorThink! So I think the original author is discussing something else or is just wrong.
The other issue is, we often
have to convert color spaces. The only reason I can think of converting from Adobe RGB to sRGB is if I needed sRGB! For the web or other emissive non color managed use. There is no such thing as an sRGB printer (or Adobe RGB printer for that matter). While some silly labs may
demand sRGB it is very easy to prove such devices do not follow anything like sRGB in their behavior. Even if someone forced me to send sRGB for output to a printer, I'd still want to start with Adobe RGB (1998) for other output needs.
Actually I'd prefer ProPhoto but that's a story summed up in this long video:
Everything you thought you wanted to know about color gamut
A pretty exhaustive 37 minute video examining the color gamut of RGB working spaces, images and output color spaces. All plotted in 2D and 3D to illustrate color gamut.
High resolution:http: //digitaldog.net/files/ColorGamut.mov
Low Res (YouTube):
http://www.youtube.com/watch?v=n0bxSD-Xx-QGentlemen, thanks for all the feedback. I did not intend to cause a rukus! And it wasn't an "article" but a post / thread on color spaces posted on the notorious web site for ignorance on all things photographic that starts with DP. I'm somewhat proficient with LR and have watched the LULA tutorials, From Camera to Print and Screen, and the Advanced LR tutorials, and "thought" I had a good handle from Jeff Schewe on colorspaces and what they're for etc., and what LR uses as a default and why that's a good thing.
In trying to be "helpful" (which for the most part was pearls before swine) on that web site, there was one fellow who seemed a little more advanced (Ryan) who was responding in a way that put me off and made me wonder if I was missing something. Hence the quote above. I'll post the link to that thread here: http://forums.dpreview.com/forums/thread/3356941 in case any of you would like to weigh in - though it is probably a waste of your time and effort, I suspect. What I would be interested in, however is your thoughts on one response I received - for my own education, if I'm missing something relevant.
The post I'm referring to is below: (I'm alsoRand47 in the post below)
Rand 47 wrote:
Ryan Williams wrote:
It still matters as you can't have an image without it existing in some kind of colour space, however the RAW itself contains no such info — only once it's brought into a RAW processor will it be assigned a profile, so in Lightroom that'd be sRGB.
Other processors may vary in what profile they use, and it's even possible the X-mount cameras could embed a meta/EXIF into the RAW file which tells the RAW processor which profile to use if it supports that option, though I doubt this is the case.
If you are saying that the native colors space for LR is sRGB, that's incorrect. LR uses ProPhoto RGB when working with RAW files. You may, of course export w/ whatever color space your image needs for its intended display mode.
A good reason to work in a large color space with RAW files is that you retain flexibility and don't throw away color information that you can never get back. Your display needs may not be able to display it now, but who knows what the future holds. The Apple retina display is close to Adobe RGB now, so sRGB is already an obsolete and too small color space for retina devices. And if you work in sRGB and someone ends up wanting a nice print of your image, well it won't be as good as it could have been, potentially, because you trashed color information that current printers can print.
Best,
Rand
No, I said for all intents and purposes it's sRGB. To be precise, it uses Melissa RGB which is a modified version of ProPhoto RGB that has the same tonality as sRGB.
Something that I'm not sure everyone understands is that colour profiles go well beyond simply allowing more colours — they can completely change the tonality and colour signature of a photo. For example, all of the X-series film simulations are colour profiles that're baked directly into the JPEGs. So using different colour profiles can have a DRAMATIC impact on how your photo looks.
In a perfect world this wouldn't be an issue because profiles are meant to embedded into files and then viewing software would show the photos using that profile. But this takes us back to my previous post: much software ignores colour profiles altogether and shows in sRGB. This includes many web browsers — the very software most of our online audiences will be using to view our photos.
So this brings me back to my original point: use sRGB or you risk people seeing them with wildly different tonality to what you intended. A wider gamut is only really useful for printing as the existence of things like 'retina displays' is completely negated by the fact that much software won't use the profiles anyway.
So what do you think? I don't want to be a bother here, as I suspect this discussion is below a threshold of interest for most - but I am interested in always being open to learning. I've learned so much from Jeff Schewe and Michael and all of you here who are genuinely knowledgable and generous with that knowledge. So let me apologize again for a tempest in a tea-pot, and express my appreciation for your help.
Best regards,
Rand
