I try extremely hard to be non-confrontational ... my mantra when posting is if I ‘m not willing to say something to someone’s face I shouldn’t write it. Despite the deep convictions of posters this thread has been pretty good about not going there, so I’m not sure why you would throw a derogatory comment like this, and the smiley doesn’t make it better.
No I”m not a scientist, I’m a career photographer who’s company has printed millions of prints, been printing custom work since the 70’s for myself and others and have been involved in digital printing technologies as well as capture since the mid 90’s, including a close relationship with Kodak and buying bleed edge capture and output devices for excessive sums of money to try learn (how about a 2mp Kodak DCS 560 camera for $22,000? ouch, what was I thinking). I’ve been working with inkjet since well before the Epson 9600 came out which sort of made it main stream, and spent years of testing and working with workflows. I have consulted with 100’s of struggling photographers who are trying to get good output from their work, and have many times had them bring me raw files so I could offer them a print far better than the file they submitted, often time the main issue being they chose to work in sRGB while in Photoshop and ended up mucking up their colors and blocking up their detail. I only offer this to show where I’m coming from what I base my practices on.
So I come from the school of hard knocks and practical experience, Bottom line while there is some logic and perhaps even some technical evidence of your position, that doesn’t make it important enough to complicate a workflow. If the difference isn’t visible, then why bother. and my eyes are pretty damn good ... as well as my experience as a printer. But to be honest this thread isn’t about me, it’s about a workflow you are promoting ... one that it seems most question is worth the effort because it won’t yield valuable enough difference in the final output.
As far as current thinking and practice, I’m surprised you don’t know this. You are the only person I know who preaches this ... and there is a pretty long list of photographers who use ppRGB as their only working space.
I think science is replete with examples of things that can be demonstrated and proven beyond what human perception is capable of discerning. That seems to me the crux of this issue.
Well, if we can’t see it, is it a color? I’ve always thought that one of the basic fundamentals of color science is that color is something in the visible human spectrum, outside of that it’s another form of electromagnetic radiation. But that’s neither here nor there ..
But I never said ppRGB did encompass all naturally occurring colors, I said "so the main goal was to try and make sure all naturally occurring colors could be defined”
Good luck to you Robert. I’m done with this thread. Despite what you think, I think most reading this thread will agree you are the one who is offering an alternative to accepted practice, and as such it really is up to you to offer some evidence as well as alternative workflows. (I’m still unclear as to an easy way to predetermine before going into PS whether or not I can contain my colors inside of a smaller space). And I know if you offer something, there will be plenty who will test it. I personally have been spending the past month testing many different ways to output my large prints with alternative sharpening methods because of the things that Bart has offered on this forum. I remember Jeff Schewe changing his position on the use of 720ppi printing from an Epson printer, despite Epsons claim it was only for vector graphics and non photographic output from discussion here on LuLa about when and why it can help. I would love to have you post some files I could use that would validate your point, and at that point even be willing to test ideas as to how to make it practical in a workflow.
But until then, John summed up this thread extremely well …
Wayne I absolutely did not intend any disrespect and I apologize for offending you. I was simply being funny (seems not!) in reply to your comment "Great you trust logic, but logic and even scientific evidence don't always equate to something that matters.". You're right, quite often logic and science tell us things that are of no practical value (at least not right now).
However the profile mapping algorithms are very much of practical interest. If a color management engineer tells you that a relative colorimetric profile essentially maps all out of gamut colors to the gamut boundary then that is very useful information. It tells you, without having to print, that if you convert a saturated image from a wide-gamut working space to a smaller-gamut working space you will get effects like flattening and banding and desaturation. This is what Andrew demonstrated in his video when he converted the image from ProPhoto to sRGB. The fault is not with sRGB ... it's with the conversion, which should not be done.
You and Andrew keep asking me to show it, prove it ... and I do, but you both seem to ignore every attempt I make. Look back here
http://www.luminous-landscape.com/forum/index.php?topic=93576.msg764493#msg764493, for example. I am showing here that if you convert the image to sRGB via the print profile which a) is a larger profile, and b) uses a perceptual mapping in this case, that the net effect on the image is minimal compared to the image mapped directly to the print space from ProPhoto. Go ahead and print the images and you will see for yourself ... I don't need to print them because I know that they will be OK. Actually, I tell you what, would you like me to prepare the images for you full-size and you can then print them yourself? Just send me the print profile you're going to use and I'll do that for you.
Regarding a Perceptual mapping to a smaller gamut. Again, I know because I have spoken to Graham Gill, who is the developer of ArgyllCMS and also because I've looked at the code (which is open-source so you can look at it yourself) that unlike a Relative mapping, the Perceptual mapping effectively squeezes the whole of the source space into the destination space, while attempting to preserve the relationship between the colors. The effect of this is a) that all the colors get shifted, and b) there is the possibility of a loss of saturation in some colors. Again, I have covered this in another thread, here:
http://www.luminous-landscape.com/forum/index.php?topic=91514.msg746328#msg746328. If you like I can make this image available to you and you can repeat the tests yourself ... but you can use one of your images, there's nothing special about the image I chose.
If you don't care about this shifting/desaturation ... well fine. I do, so I'm prepared to go this extra few yards to avoid it if I can.
You say that I am proposing a radically different working practice that very few if any photographers follow. Actually, what I am doing is attempting to correct misinformation in Andrew's video. However it isn't true that I am the only person who thinks that the choice of workspace is important and that bigger is not always better ... by no means. In an earlier post I quote Steve Upton (who appears to be highly regarded by Andrew, who directed me to the page where I got the quote from) and to requote him, he says:
In color management there is often no single correct way to do things. What we do suggest is a few things that will apply to all:
Choose a working space that is just large enough to contain your imagery; any bigger and you're wasting space.
If you can, choose a standard working space like sRGB or AdobeRGB. It makes file exchange and discussions easier
Avoid converting between working spaces as the conversions don't deal with out-of-gamut colors well
If the entire world used sRGB PROPERLY, color quality would go up significantly. What this means is that many color problems are not due to working space choices.So here is one of your own (or at least Andrew's) gurus who is telling you just what I've been saying, but in a much more concise way. Admittedly I am adding some further information, but the point here is that Steve Upton also seems to think that you are best fitting your image to a smaller space but one which still gives you some elbow room for further editing.
Which leads to your comment: "I’m still unclear as to an easy way to predetermine before going into PS whether or not I can contain my colors inside of a smaller space". It's very easy to do this. I assume you are using an (effective) aRGB monitor, so then just soft proof the image in Lightroom. If you get no monitor OOG warnings (click on the monitor icon at the top left of the histogram to turn this on) then you can safely open the image into Photoshop in aRGB. If you want to go a step further set the soft-proofing to sRGB and turn on the OOG warnings (click on the document icon at the top right of the histogram to turn this on). If you get no gamut warnings then you can safely open the image in sRGB. You can do the same with other working spaces if you wish (for example Beta RGB), but it's a little trickier opening the image as anything but sRGB, aRGB or ppRGB from Lightroom to Photoshop (but only a little bit trickier, so if you would like to know the easiest way to do this just let me know).
So that's it, no magic to it, just a bit of information from people who develop these things.
Again, let me say that I really do apologize for my flippant remark and hope you won't remain too offended by it.
Robert
