ProPhoto RGB or Adobe RGB(1998) for printing?

[ajohnw]

John - Go to the source; the ICC - http://www.color.org/chardata/rgb/adobergb.xalter

ICC shows a 8 and 16-bit (integer) standard for Adobe RGB as well as a 32-bit floating point one.

That doesn't have to relate to how the actual gamut is covered. Reading the spec carefully the essence seems to be that encoding and decoding always come back to fractions between loosely speaking 0 and 1 so the actual bit depth in a sense doesn't matter.

My view on this goes back to looking at purchasing a monitor not really all that long ago. The 1st thing that became apparent is that it wasn't clear what graphics cards would allow 30bit through. The 2nd thing that became apparent is that displays can upscale the 24bit to 30 with the associated gaps which have been commented about on the web. Then comes connection cables to the display itself. Vesa fall short in all sorts of ways now on larger displays. Looking more recently like a couple of days ago it still isn't clear to me if DVI will support 30 bit, it seems that displayport will via a rather short lead - optical may help if available and finally HDMI pass but I suspect that has display resolution limits due to it's bandwidth. My screen isn't 1080P it's 2560x1440.

Then say I produce an aRGB jpg for the web. Another grey area. Is it 8,10,12 or what. There are 2 aspects of that. If I adjust using a 10bit screen the jpg itself may be 8. I have no idea if that would matter. Doesn't matter if that is then displayed on a 32 bit FP screen if such a thing existed it would be translated to a fraction and then to 32 bit FP but it's still 8 bit info. The other aspect is part old hat. A browser will colour manage it ok but there are web pages about showing that this may not work out. All depends on tones. With colour management in browsers things have improved but .................

Also say I produce a camera aRGB - what's in that. The jpg standard is very flexible and is mainly concerned with the compression methods used - not even RGB if I remember correctly.

What I am saying is that it's rather difficult to know precisely what goes out of a PC and what happens to it when it's converted to an image that can be displayed and viewed by others. I'm left with the feeling leave it alone until it's clearly sorted out. At the moment the bandwidth to the screen seems to be a bit of a problem on large high res screens in particular. On the other hand the info I have seen may not be up to date. At this point in time it seems 85% plus PC's should be using display port - a 1m lead wouldn't reach mine.

It's crazy really because 30bit aRGB used universally would get rid of even the need for sRGB. There wouldn't be any gaps. It just becomes a sub set of aRGB that may need some minor colour management. Would it cost more? I suspect not because I strongly suspect that the main difference between the displays is the back light.

So in real terms I still feel aRGB is still a 24bit colour system.

There has been other rather miss leading info about on even PC colour depth - add an alpa channel for transparency and include it in the bit depth.

I have also read that when it comes to actual aRGB output Adobe only put 24bit out. True, old hat, pass.

John
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[Colin Southern]

Colin - the same thing can (and should) be said about people editing in AdobeRGB when their monitor is sRGB. One can only assume that the drivers and software isolate us from those "glitches", and they do a decent job mapping the colours we can't on our screens see into a reasonable versions of ones we can.

As someone who has switched to ProPhoto a few months ago, I can't say I've seen an issue (yet?). The "artificial' colours tend to be at the extreme ends of the spectrum; the fluorescent blues, neon greens, etc. but the colours that we tend to see in real images are primarily the ones we see in the more common gamuts.

The thing people need to understand is (a) what the "danger" colours are and then (b) the need to "leave the darn things alone". If they want to change them and then ensure the new colours are constrained to an sRGB colourspace then that's fine; the colours won't be accurate, but if they're pleasing then "who cares" in that respect. The big problem though is when people adjust an image that's represented in ProPhoto on an sRGB monitor ... and then print it on a wider gamut device, and wonder why some of the colours are "weird" (and then of course conclude "it must be a printer issue because they look fine on the monitor") (I've done it myself in the early days of my journey -- with 22 x 44" canvases) (which gets expensive pretty quickly!).

In some ways, processing in ProPhoto is like trying to paint a picture using invisible ink - and not being able to see the final result until the ink dries; with experience it may not be a problem, but until people realize what's going on, it's liable to bite them in the bum. Definitely a case where there's POTENTIAL to do a lot more harm than good.

[Colin Southern]

My Landscape Photography book says , ProPhoto is for fine art printing, Adobe RGB is for high quality commercial printing and sRGB is for web posting. So, if I want to print one of my images , is Adobe RGB ,which I use while editing, enough or do I need to edit the image with ProPhoto color space?

To answer the question - in my opinion - I'd say:

1. ALWAYS convert images to sRGB before posing on the web.

2. ALWAYS convert images to sRGB if having them printed commercially, unless you're 100% certain that the printer can handle other wider colourspaces (we put men on the moon in the 1960s, and yet in 2014, most street printers can't handle anything wider than sRGB)

3. If you're doing your own printing then you MAY see some advantage in sticking with Adobe RGB. BUT - if you're going to adjust the colours prior to printing - then you really need to be doing it on an Adobe RGB capable monitor that's been accurately calibrated and profiled.

With regards to ProPhoto - there's nothing wrong with it per se, but a lot of people do get caught up in the theory, not realising that "with great power comes the need for great care"; yes - in theory it's best because it can represent all the colours, but the theory and practice don't always align well. In practice the potential is there for people to make things worse, and in practice, most people wouldn't even notice the extra colours in a print anyway.

So I can see what the book is trying to say - and I won't say that they're "wrong" - but I will say that it's definitely one of those situations where the theory and the practice aren't necessarily the same for "Joe Average Photographer".

[LocalHero1953]

I think it's worth spending some time understanding how images are converted from one colour space (e.g. Adobe RGB) to another (e.g. sRGB or to a printer's colour space), a process called the rendering intent. LR and, I assume, PS offer you Perceptual Intent or Relative Intent. I have stuck with Perceptual in general, for no better reason than that when I read up on the process it sounded more logical.

However, I usually only have to worry about this for printing, because I do post processing in Adobe RGB, and my monitor can display that (so Dell says). When I print, I do a softproof in LR that shows me any out of gamut colours, i.e. colours in the Adobe RGB colour space that won't print correctly. I could allow LR to map the two colour spaces using my chosen Perceptual Intent, but what I actually do is adjust the colours in my image (usually saturation, but occasionally hue as long as it does not make the image look wrong) until there are no out of gamut colours.

My point is, that some compromises have to be made when mapping one colour space to another: I prefer to manage that process myself most of the time, because I have occasionally found (especially with plant greens and reds) that neither Perceptual nor Relative Intents produce good results: usually a bit of visible posterisation.

When exporting to jpg in sRGB for the web, I'm afraid I'm less fussy and just use Perceptual Intent.

[ajohnw]

To answer the question - in my opinion - I'd say:

1. ALWAYS convert images to sRGB before posing on the web.

2. ALWAYS convert images to sRGB if having them printed commercially, unless you're 100% certain that the printer can handle other wider colourspaces (we put men on the moon in the 1960s, and yet in 2014, most street printers can't handle anything wider than sRGB)

3. If you're doing your own printing then you MAY see some advantage in sticking with Adobe RGB. BUT - if you're going to adjust the colours prior to printing - then you really need to be doing it on an Adobe RGB capable monitor that's been accurately calibrated and profiled.

With regards to ProPhoto - there's nothing wrong with it per se, but a lot of people do get caught up in the theory, not realising that "with great power comes the need for great care"; yes - in theory it's best because it can represent all the colours, but the theory and practice don't always align well. In practice the potential is there for people to make things worse, and in practice, most people wouldn't even notice the extra colours in a print anyway.

So I can see what the book is trying to say - and I won't say that they're "wrong" - but I will say that it's definitely one of those situations where the theory and the practice aren't necessarily the same for "Joe Average Photographer".

You do sound like KR Colin but without his idiom.

One curious aspect of printing and aRGB is soft proofing so that the paper characteristics are accounted for but then just how many colours does the printer need to adequately cover an aRGB gamut? I was interested to see that Adobe reckon CMYK can't so really shouldn't printing be adjusted using a gamut that matches the printer and the paper. The problem here is that the printer probably has it's own icc file. That may have something to do with discrepancies. Not having used one this way I have no idea but it sounds like another recipe for a mess to me but I do know that it is possible to calibrate a printer as well and not doing that certainly could cause problems.

Then is seems if some do sRGB for the web - it doesn't matter so they are using aRGB or whatever purely for themselves.

I did ask some software people what happens when a package gets an out of gamut colour. The answer was that it will be clipped. What that implies is that "colour vectors" are heading for the edge of the gamut and should meet before they get there but instead don't so finish up with an incorrect colour mix.

John
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[JHzlwd]

I have always used a color managed workflow and am very pleased with the consistent results obtained. CM works. There remain some questions brought to mind by the commentary in this thread. I see the recommendation here, as in other places, that we should be using a ProPhoto working space. This makes sense, in a way, but as there are no ProPhoto monitors (that I can find) wouldn't the changes required by "rendering intent" for out-of-gamut colors make it impossible to see the ProPhoto colors anyway? Wouldn't that make it impossible truly to edit in the ProPhoto space? Then there is the matter of printers. In my experience few (if any) printers have as wide a gamut as my aRGB monitors.

My monitors are IPS technology with native Adobe RGB gamut although I custom calibrate to get the most out of them. Suppose I load a RAW (NEF, actually, because I use Nikon) and then experiment by first using the ProPhoto space as my working space and then the same one as developed for the monitor calibration (this is very close to aRGB) I cannot see any tangible difference - which is what I would expect. Although in the first instance ProPhoto will be embedded when I save that NEF as TIFF, *while I am viewing on the monitor the extended gamut colors are displayed according to "rendering intent" by mapping somewhere into the aRGB space of the monitor*.

I have seen the argument advanced that even though you cannot see the extended Pro colours on an aRGB calibrated monitor, that saving the image with ProPhoto preserves the numerical value of the original bits and this may lead to more accurate rendering when you print (although I am not entirely convinced). Well, the bits are preserved anyway unless you choose to *convert* an image (change bits to preserve appearance) so you could always embed a different profile in future if you do not convert. Having ProPhoto embedded in your images puts them in a state where future advances in presentation technology can more easily be exploited, I suppose, but shouldn't we be saving our RAWs anyway?. I am suggesting we should always prepare images in the largest color working space we can actually *see* on our monitors (which is the color space for the monitor developed by your calibration system) but does actually editing in ProPhoto contribute any advantage?

[bnnrcn]

Thanks for the intense contributions to this thread . I actually didn't know I touched such a sensitive matter when I started this thread So, I'm just following the posts without any comments or questions because I'm learning from your posts. Let's see where this thread goes

[Colin Southern]

I see the recommendation here, as in other places, that we should be using a ProPhoto working space.

Just keep in mind that a lot of that advice is just parroted from others because it sounds good in theory. In theory the interconnected oceans of the world all rise a bit when I toss in a stone too - but in both cases the "practice" isn't that cut and dried. The bigger the colourspace the less common ground there is between additive and subtractive colour devices - and thus the more care that's needed when manipulating colours on one device (monitor) that are ultimately reproduced on a device with different capabilities (printer). In my experience - often - printing in Adobe RGB is into "law of diminishing returns" category; in all the printing that I do (hundreds of canvases) the average scene or portrait won't look any different in Adobe RGB -v- sRGB. The one time I'm careful to maintain Adobe RGB throughout is reproducing some painting for a national artist; she has a very sensitive eye to colour and I have to admit that in sRGB we do get a colourshift in the cyans - Adobe RGB fixes that.

Having just said that though - in a minority of cases - sRGB can be insufficient for some of the colours required in the gamut of CMYK devices; the images don't necessarily look "bad" - they're just not colour accurate.

This makes sense, in a way, but as there are no ProPhoto monitors (that I can find) wouldn't the changes required by "rendering intent" for out-of-gamut colors make it impossible to see the ProPhoto colors anyway?

It makes sense in THEORY only, and yep!

Wouldn't that make it impossible truly to edit in the ProPhoto space?

Yep. Again, theory -v practice. Us photographers are experts in "theoretical perfectionism" - many use ProPhoto so that they don't "discard any colours" - they don't use UV filters because that extra layer of glass "must degrade image quality" - they don't shoot above ISO 200 because of the "noise" (some apparently preferring camera shake and/or subject motion to ISO "noise"!). They choose "Lens A" over "lens B" because MTF charts show it to be sharper (and they then display their images with a grossly sub-optimal sharpening workflow). They buy expensive cameras, but won't invest in equipment to profile their camera, monitor, and printer. The list - sadly - goes on. And on. And on.

Then there is the matter of printers. In my experience few (if any) printers have as wide a gamut as my aRGB monitors.

It's not so much how much of the Adobe RGB gamut they can or can't reproduce as it is the increasing lack of common ground between monitors and printers. Printers will excel at reproducing cyan, magenta, and yellows - monitors will excel at reproducing reds, greens, and blues. What's in-gamut on one won't be out of gamut on the other if one sticks with sRGB. When you go to Adobe RGB or bigger though, all bets are off.

My monitors are IPS technology with native Adobe RGB gamut although I custom calibrate to get the most out of them.

Hopefully you mean calibrate AND PROFILE them.

[ajohnw]

Yeh. Terminology can always be a problem eg calibrate and profile.

I wonder if Adobe products function in the same way as decent sites discussing colour managed work flows show it. It's also how one package I use functions.

Prophoto is just the container for the data. It's called the workspace and can also be set to other gamuts. Sticking to a prophoto setting if some one want to physically see it via monitor or a printer it passes through a gamut translation process referred to as the output profile. That can be any of them providing prophoto can contain the gamut span. It can even be prophoto itself.

2 other packages I have use 32bit floating point containers. It's completely irrelevant as far as viewing is concerned. One is purely sRGB and the other uses what ever the current system profile is.

It's pretty clear to me that prophoto also called ROMM RGB is really intended to be used like this as it contains two primaries that are imaginary. In other words they aren't colours at all so nothing can display them. I'd guess the use of pro in front of it helps not even thinking about that aspect. I mean if it has pro in it then it must be mustn't it. For actual visible primary colours wide gamut rgb makes more sense and as far as displays go may be feasible but near UV blue being about would concern me.

The thing I found interesting about the 2 threads that discussed this general area is that ICC files make no assumption about the bit depth of the gamut. - at least that seems to be the case and explains why any maths shown relating to them is always in fractions. They can be translated to any bit depth that way.

John
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[bnnrcn]

I changed my working colorspace from AdobeRGb to prophoto in order to see if there is a visible change in colors of my psd and jpg files. I mean I saved a raw file by using both colors spaces and then I saved them as pds files and then converted to sRGB and saved as jpg files. So, when I compared them to each other , I couldn't see any difference in jpgs. I think it is because I converted both files to sRGB before saving as jpgs. I could see a very slight difference in pds, blues were a bit richer in the psd with prophoto color space. But the difference was slight really.

Then I wanted to open a psd file with adobeRGB which is the color space I have used for editing my images so far. Because I changed color settings to prophoto, I get a warning indicating a profile mismatch. There were options to choose in the small warning box like 'use the embedded profile' or 'convert document's colors to the working space'. I was a bit suprised to see 'convert document's colors to the working space' because my psd was in Adobe RGB and because I saved it in the past I thought I lost some information already and it was impossible to convert to prophoto. So , I don't understand how PS CC converts an Adobe RGB psd file to prophoto If such a conversion is possible , then there is no need to argue about the matter at all. Because it is possible to reach all options whenever they are needed.

The reason why I started this thread is that, I edit my files with adobeRGB color space and I thought it might be better to edit with prophoto so that I don't lose any information while editing. What I read in my landscape photography book made me think this way.

Now, I really wonder ,if PS CC converts files from one color space to another whenever I want ( this means that I don't lose information even if I use adobeRGB color space because it is always possible to convert the file back to a wider color space which is prophoto ), then what is the point in worrying about the matter so much

[Mark von Kanel]

Binnur, there is nothing to worry about, we just like to waffle

[bnnrcn]

Very cute answer Mark.

BTW , are you still in Turkish territorial waters? Have you ever had the opportunity to get off your boat and see around?

Binnur, there is nothing to worry about, we just like to waffle

[Mark von Kanel]

We are at Kuyucak near bodrum, no i havnt been allowed off the ship and its not likly over the next few days either, i tried to get the captain to lay a stern anchor out to stop the boat swinging so i could do some star scapes.... he didnt seem impressed.....at this rate ill be reduced to taking pics of the engine room.....good job ive got all this gamut rubbish to learn about eh?

[Manfred M]

The thing people need to understand is (a) what the "danger" colours are and then (b) the need to "leave the darn things alone". If they want to change them and then ensure the new colours are constrained to an sRGB colourspace then that's fine; the colours won't be accurate, but if they're pleasing then "who cares" in that respect. The big problem though is when people adjust an image that's represented in ProPhoto on an sRGB monitor ... and then print it on a wider gamut device, and wonder why some of the colours are "weird" (and then of course conclude "it must be a printer issue because they look fine on the monitor") (I've done it myself in the early days of my journey -- with 22 x 44" canvases) (which gets expensive pretty quickly!).

In some ways, processing in ProPhoto is like trying to paint a picture using invisible ink - and not being able to see the final result until the ink dries; with experience it may not be a problem, but until people realize what's going on, it's liable to bite them in the bum. Definitely a case where there's POTENTIAL to do a lot more harm than good.

All I can say is that this has not been my experience to date.

I suspect that the behind the scenes mappings have gotten better over the various releases of both the editing software and the screen drivers, so what was an issue in the past, may be less of a risk today. Just as an arguement can be made for taking a low risk route (i.e. work in sRGB all the time), there are advantages of working with all the colours the camera and software are capable of capturing, as we know we are going to have to compress them to something the output devices are going to be able to handle. The important thing is to understand what can happen in the background and the risks involved.

[ajohnw]

Binnur, there is nothing to worry about, we just like to waffle

If I went into it any more I would feel that I need to get a life. I found a site with links to all sorts of things on the ICC's site and decided to loose the link to it. One thing it did say is that Adobe's colour management is confusing as it's meant to do all things for all people what ever they are doing with it.

It does seem though that prophoto is really intended to be a container for passing data around at a low level and can hold all other gamuts.

John
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[Mike Buckley]

If I went into it any more I would feel that I need to get a life.

I don't know why you should be concerned. Most of us seem to have given up on that long ago.

[bnnrcn]

Thanks all of you for sharing your thoughts about working color spaces. I changed my color space from Adobe RGB to ProPhoto after reading all comments. I thought I might as well take some risks

[Mark von Kanel]

Thats exactly what ive done but as it turned out i neednt have bothered because that what i was working in anyway! LR 4 only uses Prophoto ans when i edit in PS it takes on the same profile.... see i told you it was all waffle

[Richard Lundberg]

If you shoot RAW and print from your own inkjet, the only way to get rendering intents in output is to edit in ProPhoto in either Photoshop or LR (ignoring other editors for the sake of argument), let either one manage color, set the proper profiles for your printer and paper and select the rendering intent, in the print dialog. You can see the rendering by soft proofing. If you convert from ProPhoto to any smaller color space before printing, you will only get relative intent.

[LocalHero1953]

I was under the impression that I was doing exactly as you describe, Richard, but using Adobe RGB and perceptual intent. I'm away from home for a few days, so can't check.