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Author Topic: ProPhotoRGB  (Read 23790 times)
Ray
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« Reply #140 on: August 17, 2005, 09:10:24 AM »
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NO image could contain that color. Even if it could, we could see a tiny fraction of those colors (we can’t even see anything close to 16 million color simultaneously). This is all math being used to define a possible but unfortunately impossible human experience. Don’t forget, there’s math that says a bumblebee can’t fly.
I wouldn't argue with that. I suspect many of our images have no more than a few thousand discrete colors. But whether an image has 50 colors or 1,000, I don't believe the number of colors increases by moving to a larger color space.
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paulbk
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« Reply #141 on: August 05, 2005, 12:47:54 PM »
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There is nothing to debate here. It’s a closed question. The J. Daalder article is air tight. To whit:
“..if your original capture does not contain tones out of the gamut of AdobeRGB, then there is no point whatsoever (and quite a few negatives) in using ProPhoto as your color space unless you plan to artificially manipulate the saturation of your image to a considerable degree.”

I’ll go one step further, and I know nothing about color management. You don’t have to be a color scientist to understand this: If you are working in a color space you can’t print, you are doing a blind edit. That’s a fact on it’s face. The rest is a matter of degree. Working in ProPhoto it's a large degree.

What’s amusing are those who say they are preserving colors by working in ProPhoto even though they know they can’t print the colors they are “preserving.” This from the folks who say calibrate your monitor and work in a color managed environment so what you see is what you get. Well if you’re working in a color space that’s five times the size of your print space, then what you see is what you see. And any relationship between what you see and your print is good fortune.
It boggles. But if it makes you feel good, I say, enjoy! Life is too short. Where's Didger when you need him? I miss him.

Working in 16 bit is an entirely separate issue.
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paul b. kramarchyk
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« Reply #142 on: August 05, 2005, 03:04:36 PM »
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There is nothing said thus far to refute the premise of Jeremy Daalder's article. This is not about opinion. It’s about numbers. Predictable, deterministic math. It all boils down to a squirt of ink determined by a number. It’s as simple as that.

I’m not saying don’t use PhoPhoto. Use it. Have a ball. I am saying that when your working space is far greater than your printer/paper space you are knowingly introducing an unnecessary unknown. Which adds mystery to the output but nothing else of value.

If some one can explain how a color outside the print space is of some value during editing, I’ll read it. But at the moment, it’s mere religion.
Which squirt of ink and when?

The reason the working space is so much wider than the output space in many areas is it has to be. Read what Bruce wrote so clearly.

There are NO perfect working space or we’d only have one.

Trying to make a perfect fit of working space to output space (even if you only defined one printer) would be nearly impossible. Working spaces are based on synthetic color spaces that mimic displays more or less. Output devices have vastly different shaped gamuts. So for those that want to fit as much if not all the output space in the working space, you need a pretty big honking working space. So some colors WILL fall outside output gamut. That’s just a fact of life. You’re trying to fit a round peg in a square hole. The square hole has to be big enough to fit the round peg and yes, there are areas as a result that fall way outside the round peg. And that’s a problem why?

Of all the well known and designed wide gamut RGB working spaces, ProPhoto RGB has proven over the years to handle the task of a wide gamut working space. You either want to contain all the colors you capture (and maybe, hopefully reproduce them) or you don’t. It’s pretty darn easy to see if, when you’re in ACR, the scene falls within or outside of a working space like Adobe RGB (1998). IF you care about those colors, you’re far better off using a big honking space like ProPhoto RGB or you decide you don’t care about those colors. Use sRGB, use ColorMatch RGB, use whatever.

There’s far less problems gathering the color you captured in high bit in a big space than tossing the colors for a smaller space for lots of users (who care about getting all the colors they could capture). Again, you either care or you don’t. If you care, your only real option is to use a big honking color space.

There is no unnecessary unknown. There IS a big unnecessary unknown when you clip colors, namely what colors did I just throw away and what device (and when) could I have used them. Once gone, they are gone forever. I don’t see that as being a compelling reason to use a smaller working space but maybe you do.
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Andrew Rodney
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Jack Flesher
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« Reply #143 on: August 05, 2005, 06:51:32 PM »
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Jeff:

So very well said -- my compliments

I can only add emphasis to your gamut comments on the new K3 (4800) inks versus the older Ultrachrome (4000) inks.

That and the fact that my monitor is clearly the limiting factor in my digital imaging workflow at present.

Regards,
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Schewe
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« Reply #144 on: August 07, 2005, 11:32:29 AM »
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The Color Range tool offers an option to select “Out Of Gamut” colors.  Which target profile does it refer to?  It seems that the selection differs considerably from the SoftProof / out-of-gamut marks.

The Out of Gamut warnings and Color Range selections refer to whatever is the current soft proof set up. If there is no soft proof set up on, then it's the "default" set up which, unless changed, is your current CMYK profile. You can change the default by, with no image open, changing your soft proof setup to something else, such as your main Epson profile, a different CMYK, etc.

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After you’ve processed a file through Camera Raw (ProPhotoRGB, 16 bit), do you instantly enable the SoftProof to the printer/media profile, or is there an editing step in-between based on “normal” presentation on screen?

Depends-if I'm planing of taking the image directly to print, then I turn on softproofing first thing. All of my post Camera Raw tone & color corrections need to be done in "light" of the final print output. I usually turn off softproofing when just retouching.

However, if the plan is to have my converted raw file opened as a PP RGB and my plan is to just produce a master file for later use in either print, web ot whatever, then I just work along with softproofing off. Later, if I need to make a print, I turn softproofing on for checking before print.

Also, and this may surprise some, I'll also use softproofing when trying to determine optimal image sharpening-since the nature of the reduced dynamic range of the final print can have an effect on the required sharpening. Note: PhotoKit Sharpener already takes the final output into consideration when you use the Output Sharpening. That's a "product feature" we built in. But I will use softproofing to view the image for the purpose of creative sharpening.

Softproofing is _NOT_ just "all about color" it's all about what the image will look like when ink hits paper...the more you can do to prepare the image for the appearence of the image on paper, the less time you'll spend tweaking print setting, pritning a test and further tweaking.

Ink and paper are expensive enough that you can save both considerable time and money by accurate predictive image eval prior to printing. There really shouldn't be a lot of surprises when the print comes out of the printer, regardless of the working space you choose.
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Mark D Segal
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« Reply #145 on: August 07, 2005, 05:07:01 PM »
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Peter,

Here is what Relative Colorimetric rendering intent does, according to "Real World Color Management" 2003 Edition page 89:

".......It maps white in the source to white in the destination, so that white on output is the white of the paper rather than the white of the source space. It then reproduces all the in-gamut colors exactly and clips out-of-gamut colors to the closest reproducible hue. ........"

Now, if that is what it does, it is by no means obvious to me how variations in the extent of out-of-gamut colors being remapped (as you move from ARGB98 to Prophoto, e.g.) could have a differential visible impact on posterization of actual photographs.
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....." http://www.luminous-landscape.com/reviews/film/scanning_workflows_with_silverfast_8.shtml
Ray
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« Reply #146 on: August 09, 2005, 11:16:01 AM »
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The Granger Rainbow is certainly brighter and more colourful when assigned a ProPhoto profile (as opposed to sRGB and ARGB) both before and after proof setup for Premium Glossy, RelCol, simulate paper white and  sat reduction to tame gamut.

I'm not at my printer at present, but I have no doubt which would look the best if I printed all three images on my 7600.

One thing that puzzles me, however. To bring these 3 images within the gamut of the Premium Gloss profile requires a greater reduction of saturation (with the hue/sat tool) for the ARGB and sRGB images than for the ProPhoto image. (ARGB -71; sRGB -68; PP -62.) Does this seem right?
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digitaldog
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« Reply #147 on: August 17, 2005, 09:08:03 AM »
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I just can't understand that statement. I have an sRGB 24 bit 50MB image that contains every combination of the 255 levels of red, green and blue; ie 16.7 million colours, each pixel representing a different colour. (Give or take a few hundred or thousand, Jani   ).

I convert the image to the bigger ProPhoto color space. I've still got 16.7 million colors. If I were to get more, the file size would have to increase. I've never noticed that happen, have you?

If I say the colors have changed in character; that some of them are more saturated than they were in the sRGB space, then that is a different statement to saying I have more colors. Let's try to be logical here. More colors does not mean more color, if English is your first language. If you think it does, then thats the source of the confusion. By 'more colors', I mean 'a greater number of discrete shades of color'.
The scale is totally different. R255 in sRGB isn’t the same color as R255 in ProPhoto RGB. The R255R in ProPhoto is much more saturated. It’s not the same color but has the same number.

Now if you want to debate that the max red in one color space which is more saturated than another isn’t really “more colors”, OK.
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Andrew Rodney
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« Reply #148 on: August 09, 2005, 03:39:02 PM »
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It’s pretty simple. You have a capture device and scene gamut that falls outside of Adobe RGB (1998). You have output devices who’s gamuts fall outside Adobe RGB (1998) such as my Epson 2400. Your goal is to capture and reproduce all the colors you can. Adobe RGB (1998) is fine but not up to that task, ProPhoto RGB is.

As I’ve said so many times, there is no such thing as a prefect RGB working space. But you could substitute working space in that sentence with just about anything we work with in Photography and imaging.
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Andrew Rodney
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Ben Rubinstein
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« Reply #149 on: August 05, 2005, 08:40:24 AM »
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Correct me  if I'm wrong, and I think that this is what Paul has been saying all along. If my prints are made on a Fuji Frontier which prints to the sRGB colour space, then does it not make more sense to work in that colour space  from the beginning of my workflow so that I am not assuming certain saturated colours are contained in ACR using prophoto and then converting to the print colour space of sRGB just before sending to print, losing the saturated detail and having to start again.
Isn't the point of WYSIWYG to be just that? What's the point in working with a wider gamut throughout the workflow if you aren't going to use it for print, you will just be getting yourself in trouble.
Of course this is an extreme example of a printer with a limited colour space. However even though prophoto may give an advantage for certain colours on certain printers, would it not be better to work with a colour space throughout the workflow that is completely contained within the printers ability, such as Adobe '98, so at least you know exactly how the colours are going to come out in print from start to finish?
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Schewe
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« Reply #150 on: August 05, 2005, 06:30:53 PM »
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I’m not saying don’t use PhoPhoto. Use it. Have a ball. I am saying that when your working space is far greater than your printer/paper space you are knowingly introducing an unnecessary unknown. Which adds mystery to the output but nothing else of value.

If some one can explain how a color outside the print space is of some value during editing, I’ll read it. But at the moment, it’s mere religion.

It's neither a religion nor an unknown-even if _YOU_  don't yet know how to do it.

Look, you have a capture space, a working space and a printer space. To take a capture space and by virtue of converting to a working space, clip or throw away color, you've forever limited the usability of such color and lessened the value of the image for the future.

Going from ProPhoto RGB, which contains not just "most" of the colors cameras can capture, but _ALL_ colors a camera can capture, to your output profile allows _YOU_ to decide how the color transforms will be handled.

It's _NOT_ religion that today's inkjet printers can use a meaningful amount of color outside of even Adobe RGB, and it ain't just Canary yellow but in the case of the new K3 inks a LOT of dark deep saturated colors that fall outside of Adobe RGB, but within ProPhoto RGB _AND_ the K3 ink gamut.

Color outside the print gamut itself can be useful in that YOU can control how those colors are remapped. How? Photoshop Soft Proofing-if you know how to use it. The Absolute Colormetric use of Soft Proofing (using ink black and paper white) can show you exactly how to adjust what are out of gamut color into the gamut of the output device. You can alter the relationships of the colors and actual produce results by virtue of those out of gamut colors. Yes, they won't "print" but they will absolutely impact how the final output looks. Yes, today's displays can't show you "everything" but using Soft Proofing correctly, you can be about 90% accurate in your visual predictions on-screen to print.

If you don't have the data, you can't do anything with the data...hense the reason for working with data outside of the color space of the output and if you know what you are doing, working with data outside the color space of your monitor.

Personally, with the recent rate of progress in cameras, output devices and displays, if you _DON'T_ work now with an eye to the future, you are being incredibly short sighted. Michael's review of the 4800 not withstanding, the total volume of color capable of being reproduced by the 4800 vs the 4000 is seriously larger-even if he didn't do the volume mapping to prove it to himself.

We'll have computer displays very shortly that will have at least if not larger color gamuts than Adobe RGB and luminance output that is bright enough to work in normal room light.

To be honest, even ProPhoto RGB is actually too small a color space to work in when limited by 16 bit. With the deployment of even limited HDR space in Photoshop CS2, we're looking well beyond the current limitation of 16 bit integer to 32 bit floating point and new color spaces that will extend even beyond what ProPhoto RGB can contain.

Will we see cameras that can capture or printers that can print it? Not for a while yet, but remember, image processing is also an advancing art and still limited to the current algorithms in use-which keep getting better. But even if you can't capture or print the colors, you CAN archive them in your files for a time in the future when you may be able to. Also, understand that image processing is just really elaborate math-and the more data you have, the more refined and accurate the results of your processing algorithms. Which translates to better results even in smaller gamut output.

There are a lot of people out there with a little bit of knowledge and often the "nearly blind" will end up leading the "blind". The "unknown" won't stay that way long, and there's little value in "religion" as you term it...but there is science, if you are inclined to learn it.
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Hermie
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« Reply #151 on: August 05, 2005, 01:21:21 PM »
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By the way, does anyone of you use

- basICColor display profiles (gamut-compressed profiles, which reasonably simulate colors outside the monitor gamut) or
- Photoshop's "Desaturate Monitor Colors" control

in relation to ProPhoto workflow?

Herman
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paulbk
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« Reply #152 on: August 05, 2005, 03:29:03 PM »
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You realize that when a photo file color doesn’t map into your print space the rendering process does it for you. In other words, what you see is NOT what you get. You get whatever the rendering process gives you. That’s why in 2005 we still hover over the printer with a fair bit of apprehension to see what it will hatch. We don’t do that with text printers any more because technology has taken the mystery out of it. Back in the DOS days of 6 pin dot-matrix printers it wasn’t so deterministic. Some day fine art printing will be as deterministic as laser jet text is today. But it won’t be tomorrow.
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paul b. kramarchyk
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« Reply #153 on: August 08, 2005, 09:17:01 PM »
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Andrew's response to Ray to-day is very sensible, but it deals with varying impacts of different rendering intents, whereas the issue at stake in this discussion thread is whether there is a differentially worse impact from the use of whatever rendering intent when the working space is Prophoto rather than ARGB98.
Actually if you’re referring to the use of a Granger Rainbow to see the effects of a conversion, the source profile used is going to be part of the evaluation. That is, Assign sRGB, Adobe RGB (1998) and ProPhoto to the same numbers and convert using the same output profile and rendering intent. You’ll see some very interesting results!
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Andrew Rodney
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Ray
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« Reply #154 on: August 09, 2005, 08:26:11 PM »
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Brighter appearing when you Assign or after you’ve output the file?
Brighter (more saturated, or perhaps more intense is the right word) on screen immediately after assigning the 3 profiles, but also after applying proof setup/simulater paper white etc and reducing gamut for all 3. The sRGB and ARGB rainbows are dowdy by comparison.

If the numbers are the same, it would seem the reason why the ProPhoto image did not require the same degree of desaturation as the ARGB image (to bring them both within gamut) is a result of the Premium Glossy paper's capacity to handle at least some of the greater saturation of ProPhoto. Does that make sense?

The surprise is, the sRGB image required less desaturation to bring it within gamut than did ARGB. It would make more sense if this was the other way round.
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PeterLange
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« Reply #155 on: August 07, 2005, 06:13:11 PM »
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Mark,

I do not see any contradiction, unless you seriously suggest to map an out-of-gamut color onto an in-gamut color.

With RelCol, out-of-gamut colors are simply clipped to the nearest color in CIE Lab. In detail, an out-of-gamut color is moved along a line of constant Lab hue angle – until it reaches the border of the target space.

At page 71 of your book it is explained that such moves are not perfectly in line with the perceived hue.

Peter

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digitaldog
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« Reply #156 on: August 10, 2005, 11:38:26 AM »
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There are two options for viewing out of gamut colors under the View menu. One is to setup a soft proof using the output profile, rendering intent and options like Simulate paper/ink. This IS the way to be evaluating the soft proof/out of gamut colors.

The second, older and quite useless way is to pick “Gamut Warning” which places a gray (by default) mask over out of gamut colors based on what you’ve set in Proof Setup. The idea is to desaturate those areas so they fall into output gamut. This is a old, useless, time consuming and not very accurate way to be handling this process.
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Andrew Rodney
Author “Color Management for Photographers”
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