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Author Topic: What workspace profile?  (Read 15855 times)
John McDermott
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« on: December 08, 2007, 12:42:49 PM »
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This question is aimed primarily at Jeff Schewe. I have bought and watched both your LR and C2P tutorials in which you recommend using Prophoto as the working space profile (Ialso bought your Camera Raw & CS3" book but just received it today so haven't had the time to read it yet). However, I am also a customer of Cathy's Profiles and in her latest documentation she makes the following recommendation:

"When the image color space is ProPhoto RGB it is much larger than the printer color space. The profile must compress the image color space into the much smaller printer color space and this may cause poor quality prints unless you have expert editing skills. It is much easier to achieve excellent results when the image color space is approximately the same size as the printer color. These types of problems are not a reflection on the quality of the profile but instead reflect on the ability of the person using the profile."

The result of her argument is to use Adibe RGB (1998) instead.

I'm not smart enought to evaluate the validity of her argument so I thought I'd ask for your opinion. Obviously you prefer ProPhoto RGB, but please elaborate on your reasoning.
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David White
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« Reply #1 on: December 08, 2007, 04:01:32 PM »
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I'm not Jeff and there are several facets to your question that need answering.  The only one I will address is the misstatement about having to compress the image to fit it into the printer's color space if ProPhoto is your working space.  

The profiles I made for my Canon IPF5000 easily exceed the gamut of Adobe RGB in several areas of the color space.  By not using ProPhoto I would be throwing away the extra image gamut available outside of Adobe RGB from my printer.
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David White
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« Reply #2 on: December 08, 2007, 04:45:14 PM »
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http://www.adobe.com/digitalimag/pdfs/phscs2ip_colspace.pdf

Gamut mismatch (fitting round pegs in square holes):

There are way, way more colors that can be defined in something like ProPhoto RGB than you could possibly output, true. But we have to live with a disconnect between the simple shapes of RGB working space and the vastly more complex shapes of output color spaces to the point we're trying to fit round pegs in square holes. To do this, you need a much larger square hole. Simple matrix profiles of RGB working spaces when plotted 3 dimensionally illustrate that they reach their maximum saturation at high luminance levels. The opposite is seen with print (output) color spaces. Printers produce color by adding ink or some colorant, working space profiles are based on building more saturation by adding more light due to the differences in subtractive and additive color models. To counter this, you need a really big RGB working space like ProPhoto RGB again due to the simple size and to fit the round peg in the bigger square hole. Their shapes are simple and predictable. Then there is the issue of very dark colors of intense saturation which do occur in nature and we can capture with many devices. Many of these colors fall outside Adobe RGB (1998) and when you encode into such a space, you clip the colors to the degree that smooth gradations become solid blobs in print, again due to the dissimilar shapes and differences in how the two spaces relate to luminance.
« Last Edit: December 08, 2007, 04:46:16 PM by digitaldog » Logged

Andrew Rodney
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« Reply #3 on: December 08, 2007, 04:53:41 PM »
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"When the image color space is ProPhoto RGB it is much larger than the printer color space. The profile must compress the image color space into the much smaller printer color space and this may cause poor quality prints unless you have expert editing skills. It is much easier to achieve excellent results when the image color space is approximately the same size as the printer color."
[a href=\"index.php?act=findpost&pid=159279\"][{POST_SNAPBACK}][/a]


Well, the above quote is simply wrong...nothing about printing is "EASY" and trying to make people think a smaller working space will make anything easier is naive at best and disingenuous at worst.  

The "size" of the working space is not really an active factor when determining the "skill level" required on the part of the user. Yes, ProPhoto RGB is a really, really big space. I use it to make sure colors that my camera can capture and colors that my printer can print don't get clipped by a smaller working space.

As gvdavewh says, there's a lot of color that _CAN_ be printed on today's high-end pigment printers that can't be contained in Adobe RGB. So, working in Adobe RGB not only clips colors your camera is capturing but that can be printed.

As long as you have an accurate display profile and an accurate printer profile, there's no particular GREATER difficulty using ProPhoto RGB than any other working space and several benefits.

But the choice of working space is really something people need to determine themselves...listening to ANYBODY else is really avoiding the issue by avoiding doing the testing and making a determination, based on the results, for oneself...if you want to make maximum use of the camera colors and the printer colors, as I do, then there's really only one choice of working space. If those issues aren't important–and only YOU can determine that–then use the space that works the best for you.
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John McDermott
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« Reply #4 on: December 08, 2007, 07:06:25 PM »
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 Thank you Jeff (and others) for explaining and clarifying that for me. When I saw the quote on Cathy's Profiles it surprised me as I had never heard that before. I can now file it under "old wive's tales".
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digitaldog
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« Reply #5 on: December 08, 2007, 08:39:31 PM »
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When I saw the quote on Cathy's Profiles it surprised me as I had never heard that before. I can now file it under "old wive's tales".
[a href=\"index.php?act=findpost&pid=159347\"][{POST_SNAPBACK}][/a]

Cathy may have the mechanics of building profile down but she's pretty confused about their use and role in the entire color management workflow.
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Andrew Rodney
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« Reply #6 on: December 10, 2007, 05:58:02 AM »
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In LR the standard color spaces are ProPhoto RGB, Adobe RGB and sRGB. Most, if not all photographers never need anything else. Today the fashion is to use ProPhoto RGB as your standard color working space. Most of the times, with the use of 16-bit images, it’s a safe color space.

… but knowledge about color management is vital and not all recognize problems when they encounter them. It’s my opinion ProPhoto RGB is NOT recommended when people know nothing about the basics behind all this. Selecting a small color space like sRGB can result in loss of saturated color and loss of detail when clipping is significant. Fortunately many images don’t benefit from a wide gamut color space, because it never contained any colors outside sRGB to begin with.

I mostly work in a studio environment and my subjects are models. Skin tones are important and fall easily inside the sRGB container. When the background, make-up or clothing contains colors outside sRGB, I can benefit from a wider color space like ProPhoto RGB. I have to do this with caution; because I sometime notice that my skin tones fall apart when I need to edit them, even with 16-bit images. I choose sRGB in LR instead and sacrifice some colors outside sRGB, but got better skin tones.

Bottom line is that I think the image data is the determining factor when selecting a working color space. Do you need ProPhoto RGB? If your answer is no, a smaller color space is all you need and in my opinion is the better choice.

[span style=\'font-size:8pt;line-height:100%\']I most often use ProPhoto RGB, I regulary use sRGB and seldom use Adobe RGB (all 16-bit)[/span]
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billg71
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« Reply #7 on: December 13, 2007, 09:07:43 PM »
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I used to do most of my work in Nikon's Capture NX using aRGB space as the default color space and often had horrible problems with out-of-gamut areas on my prints.

Now I have NX, LR and CS3 all set to ProPhoto and haven't had the out-of-gamut blobs and blotches. Yet....

Just my $.02/worth, YMMV.

Bill
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[span style='font-size:7pt;line-height:100%'][span style='color:blue']"The doctor told how he was once fishing in the Wind River area of Wyoming and he looked up and far above on the side of the canyon two dogs sat on a rock peeking at him from the brush that surrounded the rock. Only they weren't dogs, they were coyotes. They were curious about what he might be doing standing in a river waving a stick." [span style='color:black']Jim Harrison, Farmer[/span][/span][/span]
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« Reply #8 on: December 13, 2007, 10:07:09 PM »
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The concept of using larger color spaces just make sense.  It is easier (and I use that term relatively, Jeff   ) to work your way down to the printer's space than it is to just lop off color info by starting in a color space that is smaller than what your camera sees.  When you start there you've already lost some of the artistic and critical control.

Jeff is correct in that printing is not easy.  So why make it harder by tying some pixels behind your back at the start?  
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billg71
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« Reply #9 on: December 13, 2007, 11:14:04 PM »
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The concept of using larger color spaces just make sense.  It is easier (and I use that term relatively, Jeff   ) to work your way down to the printer's space than it is to just lop off color info by starting in a color space that is smaller than what your camera sees.  When you start there you've already lost some of the artistic and critical control.

Jeff is correct in that printing is not easy.  So why make it harder by tying some pixels behind your back at the start? 
[a href=\"index.php?act=findpost&pid=160563\"][{POST_SNAPBACK}][/a]

Good point, Gene. I think of it as limiting precision, for example, setting up an Excel spreadsheet and limiting it to 2 decimal places of precision. The first 4 or 5 calculations, it won't make a difference. After a few million iterations, it's more than likely the output will differ significantly. Banks and credit card companies make millions every year on small fractions of a decimal point. Who knows how many calculations are run on an image when you sharpen, reduce noise, crop, adjust levels, etc. in any editing program?

Manipulating data at the highest precision possible is a no-brainer. No matter what you do to it, you'll always end up with the result that most closely matches the input. The final step is to reduce that result to a usable number, that's where you do all the rounding. Whether it's to display as two decimal points in a spreadsheet or to send to a printer, you'll always get the most accurate results by maintaining the highest precision possible throughout the process.

In photo terms, you start with the widest range of data available, maintain that range throughout the editing process and then reduce the final output to something the export device is capable of handling. Doing anything less is literally throwing away data you worked hard to capture in the first place.

Bill
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[span style='font-size:7pt;line-height:100%'][span style='color:blue']"The doctor told how he was once fishing in the Wind River area of Wyoming and he looked up and far above on the side of the canyon two dogs sat on a rock peeking at him from the brush that surrounded the rock. Only they weren't dogs, they were coyotes. They were curious about what he might be doing standing in a river waving a stick." [span style='color:black']Jim Harrison, Farmer[/span][/span][/span]
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« Reply #10 on: December 14, 2007, 04:26:59 AM »
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There are two aspects competing with each other and using the largest color space is not giving you the highest precision.

The smallest color space will give you the highest precision of color manipulation. The data points (colors) are closest to each other in the smallest color space. ProPhoto RGB will give you a larger color gamut, but the data points are also wider apart. With 16-bit channels its most of the time not a big problem and one can safely use this as a standard color space so long you keep an eye on (rare) problems. As I said in my earlier post, sometimes even 16-bit colors can be insufficient (in a large color space) and manipulating these delicate colors can give banding.

Highest precicion: 16-bit channels and sRGB color space.
Lowest precicion: 8-bit channels and ProPhoto RGB color space.
« Last Edit: December 14, 2007, 04:29:30 AM by Hendrik » Logged
digitaldog
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« Reply #11 on: December 14, 2007, 08:22:30 AM »
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There are two aspects competing with each other and using the largest color space is not giving you the highest precision.

The smallest color space will give you the highest precision of color manipulation.
[a href=\"index.php?act=findpost&pid=160609\"][{POST_SNAPBACK}][/a]

That is true. The colorimetric differences between two 'adjacent' colors if you will have a higher deltaE in a larger than smaller color space. Just another reason why as the spaces get larger, you really DO want to be working in a higher bit depth.

This is really more an issue for displaying the data these days, far less so for editing (the majority that should be done in the Raw converter, linear high bit wide gamut). If you're working on very subtle colors in an image, its going to be much harder to see them on a wide gamut display than an sRGB like device.
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Andrew Rodney
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« Reply #12 on: December 14, 2007, 10:07:26 AM »
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In line with I guess it would not make sense to work in a Prophoto space with 8 bit colors and it does make sense for skin tones to use sRGB with 16 bit colors...

I already notice working in Photoshop with curves that when I use the Prophoto space subtle color correction becomes more difficult than when I use the sRGB space
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Pieter Kers
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« Reply #13 on: December 27, 2007, 11:51:45 PM »
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I have to ask a question here.  On my cameras the color space is set to Adobe RGB.  I shoot all in RAW.  Am I capturing in Adobe and then opening in ProPhoto in LR?  Is it just a waste of extra color space then?  Am I creating new colors when I edit?
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« Reply #14 on: December 28, 2007, 12:19:46 AM »
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There are two aspects competing with each other and using the largest color space is not giving you the highest precision.

The smallest color space will give you the highest precision of color manipulation. The data points (colors) are closest to each other in the smallest color space. ProPhoto RGB will give you a larger color gamut, but the data points are also wider apart. With 16-bit channels its most of the time not a big problem and one can safely use this as a standard color space so long you keep an eye on (rare) problems. As I said in my earlier post, sometimes even 16-bit colors can be insufficient (in a large color space) and manipulating these delicate colors can give banding.

Highest precicion: 16-bit channels and sRGB color space.
Lowest precicion: 8-bit channels and ProPhoto RGB color space.
[a href=\"index.php?act=findpost&pid=160646\"][{POST_SNAPBACK}][/a]

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That is true. The colorimetric differences between two 'adjacent' colors if you will have a higher deltaE in a larger than smaller color space. Just another reason why as the spaces get larger, you really DO want to be working in a higher bit depth.

This is really more an issue for displaying the data these days, far less so for editing (the majority that should be done in the Raw converter, linear high bit wide gamut). If you're working on very subtle colors in an image, its going to be much harder to see them on a wide gamut display than an sRGB like device.
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Hendrick and Andrew,

Please I am confused by the use of the term "precision".  I cannot believe that using a sRGB colorspace would lead to more precision just less choice so easier decisions.  What did I miss?

Tom
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John.Murray
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« Reply #15 on: December 28, 2007, 12:19:58 AM »
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I have to ask a question here.  On my cameras the color space is set to Adobe RGB.  I shoot all in RAW.  Am I capturing in Adobe and then opening in ProPhoto in LR?  Is it just a waste of extra color space then?  Am I creating new colors when I edit?
[a href=\"index.php?act=findpost&pid=163528\"][{POST_SNAPBACK}][/a]

The Adobe RGB colorspace only applies to jpeg images produced by the camera.  

hth - John
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method
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« Reply #16 on: December 28, 2007, 01:28:07 AM »
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On my cameras the color space is set to Adobe RGB.  I shoot all in RAW.  Am I capturing in Adobe and then opening in ProPhoto in LR?  Is it just a waste of extra color space then?  Am I creating new colors when I edit?
[{POST_SNAPBACK}][/a]

You assign the working space in the software at conversion time. It is one of the the great advantage of RAW!

Richard Earney

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[a href=\"http://inside-lightroom.com]http://inside-lightroom.com[/url]
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Hendrik
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« Reply #17 on: December 28, 2007, 05:07:32 AM »
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Hendrick and Andrew,

Please I am confused by the use of the term "precision".  I cannot believe that using a sRGB colorspace would lead to more precision just less choice so easier decisions.  What did I miss?

Tom
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I will use an analogy of a stair.

The height of the stair determines the color gamut. If you go higher, the colors will become more saturated.

ProPhoto RGB is a very high stair, you reach a high altitude with it. With 8-bit, you only have 255 steps to reach the upper part of ProPhoto RGB.

sRGB is not so high compared to ProPhoto RGB, in a matter of fact, it’s a very low stair. To reach the upper part of this low sRGB stair, you also have 255 steps. Because the stairs have a different height, but the same amount of steps, the steps of the sRGB stair must be much closer spaced compared to the ProPhoto RGB stair.

This is the reason you have finer control in a smaller color space. The colors are closer to each other.
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digitaldog
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« Reply #18 on: December 28, 2007, 09:08:52 AM »
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I have to ask a question here.  On my cameras the color space is set to Adobe RGB.  I shoot all in RAW.  Am I capturing in Adobe and then opening in ProPhoto in LR?  Is it just a waste of extra color space then?  Am I creating new colors when I edit?
[a href=\"index.php?act=findpost&pid=163528\"][{POST_SNAPBACK}][/a]

Raw has no color space. And it doesn't matter what you set your camera to (you're shooting Raw).

In a modern Raw workflow, I don't see the need for Adobe RGB (1998) at all. I encode in ProPhoto since its the widest color space I have available in my converter, this converter is using the ProPhoto primaries anyway after the Raw goes through its demosaicing, and lots of images and some output devices exceed Adobe RGB (1998). So, its Raw in, ProPhoto RGB in 16-bit out.
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Andrew Rodney
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« Reply #19 on: December 29, 2007, 01:00:23 AM »
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I will use an analogy of a stair.

This is the reason you have finer control in a smaller color space. The colors are closer to each other.
[a href=\"index.php?act=findpost&pid=163565\"][{POST_SNAPBACK}][/a]

So if I created a monochrome gradient in 8bit RGB with sRGB it would be smooth while the same gradient with ProPhoto would be banded?  This problem would simply go away by switching to 16bit RGB

Why are we doing 8bit for anything other than web display anyway?

Tom
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