Pro RGB...really?

Started Nov 8, 2012 | Discussions
rpenmanparker
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Pro RGB...really?
Nov 8, 2012

In order to jump start my home printing effort I recently engaged a tutor at the Houston Center for Photography for a few one-on-one sessions re: image output and color management. He was really excellent, and truly got me up and running.  Two changes to my practice that he recommended were shooting and post processing in RAW and working in an expanded color space like Pro RGB. I get the RAW and quickly have become a convert. I am less convinced about the Pro RGB however. The more I read about it, the more I see cemments about neither my standard LCD monotor or pro-am printer (Canon PP 9000 Mk II) being able to reproduce the extra gamut. So what is the point?  To avoid incompatibilities I am switching color space back and forth depending upon What type of image file I am opening, and that is a pain.  Most files that come my way except ones that I am creating are sRGB.   If  there isn't going to be a difference in display appearance or output, why am I fooling around with this?  Amd how does color space relate to printer profiles.  Does the profile "know" about colorspace?  Does it convert output to a smaller space anyway?  Does the  profile have to be produced from a test image created in the same color space as the images which will be printed?  Whew!  I am really getting woind up here. Any advice and discussion regarding all this will be appreciated.  BTW, I guess I have the same questions about Adobe RGB. Anything different there? Thanks.

Robert

JohnJ851
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Re: Pro RGB...really?
In reply to rpenmanparker, Nov 9, 2012

Hi

A link to read about sRGB vs aRGB reg printing:  www.cambridgeincolour.com/tutorials/sRGB-AdobeRGB1998.htm

JohnJ

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Hugowolf
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Re: Pro RGB...really?
In reply to rpenmanparker, Nov 9, 2012

First, it is ProPhotoRGB not Pro RGB. It is a color space developed by Kodak specifically with the wide gamuts available from input devices like digital sensors in mind. It isn’t an output space for any current device; it is a working space for development and editing. Using it preserves most of the gamut from your camera.

At some point, if you create a file destined for display on a monitor, projector, or printed media, then the image needs to have its gamut compressed into a smaller space, and some would argue for doing this immediately on conversion. But in compressing at that early stage, you are literally throwing away data, just as if you were to shoot sRGB jpg, or even more so, if you were to have the camera convert to black and white immediately after shooting.

Look at Adobe Photoshop Lightroom. Its native working space is ProPhotoRGB. Modifications in Lightroom are performed using ProPhotoRGB, but using a linear gamma (so called MelissaRGB). Image previews are rendered using AdobeRGB, and printing is mostly done using a much smaller ICC profile specific to your paper and printer. Color management is not a simple issue.

Brian A

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technoid
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Re: Pro RGB...really?
In reply to rpenmanparker, Nov 9, 2012

I have mixed feelings about ProPhotoRGB. On the one hand, as others have pointed out, it has a wider gamut and can encompass vritually all of what a camera's sensors can capture. OTOH, it far exceeds what any monitor can do let alone monitors that are only sRGB capable. The latter means that you can easily create colors that can't be produced on your monitor. If you have a lot of highly saturated colors it is quite easy to create a very pleasing image that wouldn't look right at all on a larger gamut monitor.  And then there is the issue of printing. While all colors within a printer's gamut are within ProPhoto's gamut, the opposite is far from true. At least with printers it's easy to check where in an image colors are out of gamut (View proof in Photoshop) and one should always check this before printing.  Fortunately, most (though not all) images one encounters do not exceed sRGB and of the ones that do, they almost always fall within Adobe RGB. The best reason to use ProPhoto RGB is the certainty that you will be able to work with any color your printer is capable of printing and this is not true of sRGB or Adobe RGB where printers often have gamuts that exceed them in certain areas. Most typically in cyans in the midrange of luminousity. However, doing so requires more care to make sure either that colors you see on the screen when adjusting images are within the gamut your particular monitor or, alternatively, that you have some other way to determine the correct color is being used, a path few tread.

One other factor using ProPhotoRGB is that you should always work in 16 bit mode. Because each adjacent hue is further apart in ProPhoto, 8 bit values increase the risk of artifacts when you have areas of gradual color shifts such as in skies.

Here's an example where a camera can capture an image that won't even fit into ProPhoto. Sunlight exiting a prism being split into the color spectrum. The colors are actually right at the edge of the classic horseshoe gamut. They are within the gamut of the camera's sensor and hence RAW files, but exceed every working colorspace. Their true colors are unprintable and unviewable on monitors without a great deal of desaturation. ProPhoto can represent them better than other spaces but they still have to be displayed on an actual monitor.

Until you are comfortable with colorspaces (and they can sure seem confusing) I would recommend sticking with sRGB or AdobeRGB if you have a profiled, wide gamut monitor.

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rodbam
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Pro Photo, maybe not.
In reply to rpenmanparker, Nov 9, 2012

A friend was having a problem with banding showing in his sky & he said he didn't do much processing on it to cause the banding, he uses Pro Photo colour space. He found this article & now uses aRGB & he get's no more banding.

The article is very dubious about the benefits of using Pro Photo.

http://www.stumbleupon.com/su/9dwVhv/:1bELgf%20Id:H2zXjaIC/www.imagescience.com.au/kb/questions/85/January2005-ProPhotoorConPhoto/

How do we post an active link?

Regards Rod

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jtoolman
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Re: Pro Photo, maybe not.
In reply to rodbam, Nov 9, 2012

Rod, I just copy and paste a URL and it pastes as an active list.

I just did that on another thread.

This is teh Total URL from the actual site on your posted link.

http://www.stumbleupon.com/su/9dwVhv/:1bELgf%20Id:H2zXjaIC/www.imagescience.com.au/kb/questions/85/January2005-ProPhotoorConPhoto/http://www.stumbleupon.com/su/9dwVhv/:1bELgf%20Id:H2zXjaIC/www.imagescience.com.au/kb/questions/85/January2005-ProPhotoorConPhoto/

When I pasted it from your text it pasted as text.

When I pasted it after copying it from the actual sites ( I looked that site up on my browser ) it pasted as an active link.

But here it is copied from your post:

http://www.stumbleupon.com/su/9dwVhv/:1bELgf%20Id:H2zXjaIC/www.imagescience.com.au/kb/questions/85/January2005-ProPhotoorConPhoto/

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technoid
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Re: Pro Photo, maybe not.
In reply to jtoolman, Nov 9, 2012

This:

http://www.imagescience.com.au/kb/questions/85/January+2005+-+ProPhoto+or+ConPhoto

It mirrors my concerns expressed in the earlier post.

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Petruska
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Great article!
In reply to technoid, Nov 9, 2012

I don't know why anyone that is printing would edit in ProPhoto color space as wide gamut monitors are going to show hues that can't possibly print....

Here is a comparison of the color spaces to the gamuts of the the Epson 2880 and 4900 and as you can see you can't print all the colors of any color space.

Bob P.

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Hugowolf
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Re: Pro Photo, maybe not.
In reply to rodbam, Nov 9, 2012

My keyboard only has uppercase sans serif characters, but that doesn't stop me from using lowercase, serif, bold, and italic. My screen is not particularly adept at showing the finer points of fonts, but that doesn't stop me from using them. My screen hardly shows a difference between the original 1957 Helvetica and the redesigned 1983 Helvetica Neue, but the differences are there in print. My screen can only approximate the light, ultra light, thin, condensed, expanded, or the 51 different font weights. For critical work, nothing beats a hard proof.

In painting, not just fine art painting, the paint dries to show a slightly different color than when wet. Inks do this too, but to a lesser extent. There are lots of examples of where tools aren't capable of revealing the scope of a work until the end. Experience is critical. I really can't go along with the idea of letting the monitor be a limiting factor.

Wide gamut working spaces have their known problems. Some of the triplets in ProPhotoRGB aren't reproducible as colors. Posterization, especially in large blue areas when using 8 bit processing, can occur during certain editing techniques.

In most cases it is a moot question. The only times I found initial compression to Adobe or sRGB to be a problem is with art repro. In most cases it doesn't matter what the original scene was like, as long as the print has the aesthetics to sell. (If you use Lightroom for most of your processing, then it is definitely a moot question.)

Brian A

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Hugowolf
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Re: Great article!
In reply to Petruska, Nov 9, 2012

Petruska wrote:

I don't know why anyone that is printing would edit in ProPhoto color space as wide gamut monitors are going to show hues that can't possibly print....

Here is a comparison of the color spaces to the gamuts of the the Epson 2880 and 4900 and as you can see you can't print all the colors of any color space.

Bob, your point is well taken, but we are talking about working spaces not output spaces. At some point before ink hits paper the gamut of the original scene has to be reduced considerably. The question is when is it best to do that. Is it better to do that before processing or just before printing (or posting or projecting)?

Brian A

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rpenmanparker
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Re: Great article!
In reply to Petruska, Nov 9, 2012

So Bob, what do you recommend?  First for opening RAW in a converter. Then for exporting to a full function editor. What do you use as a color space for the files that you print? Thanx.

Robert

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Vernon D Rainwater
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Re: Great article!
In reply to Petruska, Nov 9, 2012

Petruska wrote:

I don't know why anyone that is printing would edit in ProPhoto color space as wide gamut monitors are going to show hues that can't possibly print....

Here is a comparison of the color spaces to the gamuts of the the Epson 2880 and 4900 and as you can see you can't print all the colors of any color space.

Bob P.

As part of a project to create a two color mixing chart for our Great Grand Daughters, we downloaded a Basic Color Wheel that was in aRGB. I measured each of the areas using Photoshop Info sampler -- while in aRGB.

Then, converted the entire file to sRGB and saved to a different file name and Measured each of the areas using Photoshop Info sampler -- while in sRGB.

The below color groups were significantly different for the two color types with RGB values as indicated on the Color Wheel.

There is no wonder why there are significant differences for printed Photo image File(s) in aRGB as compared to sRGB.

Even though some of the other color modes are reported as being better, my preference is to use sRGB throughout the entire Photo Image processing and printing. This has helped me to get more consistent results with excellent printed Photos.

Yellow / Green

Blue (a slight difference)

Blue / Violet

Violet

Red / Violet

Red /Orange (a slight difference)

Bob, I would appreciate any comments you may offer.

-- hide signature --

Vernon...

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alvie
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Re: Pro RGB...really?
In reply to rpenmanparker, Nov 9, 2012

rpenmanparker wrote:

In order to jump start my home printing effort I recently engaged a tutor at the Houston Center for Photography for a few one-on-one sessions re: image output and color management. He was really excellent, and truly got me up and running. Two changes to my practice that he recommended were shooting and post processing in RAW and working in an expanded color space like Pro RGB. I get the RAW and quickly have become a convert. I am less convinced about the Pro RGB however. The more I read about it, the more I see cemments about neither my standard LCD monotor or pro-am printer (Canon PP 9000 Mk II) being able to reproduce the extra gamut. So what is the point? To avoid incompatibilities I am switching color space back and forth depending upon What type of image file I am opening, and that is a pain. Most files that come my way except ones that I am creating are sRGB. If there isn't going to be a difference in display appearance or output, why am I fooling around with this? Amd how does color space relate to printer profiles. Does the profile "know" about colorspace? Does it convert output to a smaller space anyway? Does the profile have to be produced from a test image created in the same color space as the images which will be printed? Whew! I am really getting woind up here. Any advice and discussion regarding all this will be appreciated. BTW, I guess I have the same questions about Adobe RGB. Anything different there? Thanks.

Robert

I live on the Island and would like to have a tutor run me through the art of printers and printing.  Some of the advise given here on dpreview is great, but sometimes its a little too technical for me.  I perfer to have a one on one session.  Can you please tell who can I speak with at HCP in order to make an appointment for a session?

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technoid
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Re: Great article!
In reply to Vernon D Rainwater, Nov 9, 2012

The only reason not to use sRGB is if the captured image has printable colors outside of sRGB. Most images don't. Those do not benefit from the larger gamut working spaces.

I have a wide gamut monitor but usually work in monitor sRGB. My monitor, an EIZO 301W, has been profiled for "native" and sRGB emulation. I only switch to "native" when I need to work in a larger space because the image contains colors outside sRGB. The rest of the time I prefer to just leave the monitor on sRGB emulation as the colors for all my other apps and desktop are too saturated otherwise.  Of course Photoshop displays these images the same whether sRGB or native as there is nothing to gain when the images are inside sRGB.

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Petruska
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Brian....
In reply to Hugowolf, Nov 9, 2012

Now maybe I just don't understand and you correct me where I'm wrong.

If one looks at my gamut chart in my above post, and I have PhotoShop/Lightroom set for ProPhoto  "working" color space and let's just say I have a wide gamut monitor that can produce 100% ProPhoto colors.  So now I have this photo on the monitor that shows the blue skies of the ProPhoto blues in the the lower left corner of the ProPhoto gamut and the the bright green grass of the ProPhoto greens in the upper left corner of the ProPhoto gamut and now I edit keeping those colors on my screen as true as possible.  Now when I soft-proof and print I will never have any of those blues and greens, I wasted my time editing/looking at the beautiful blues and greens.

Now if I start with a sRGB working space,  edit in sRGB, soft-proof and print in sRGB I'm sure going to be much, much closer of getting the print to match what I see on the monitor.  If I'm doing a lot of editing I don't want to edit, then look at soft-proof to say hey I got to go back and change my colors as I can't print them correctly.

I even stopped capturing my photos in AdobeRGB, because the gamut warning in PhotoShop was much more than capturing in sRGB, editing in sRGB, and printing in sRGB.

Maybe I am off with all this but it's my take on the subject.

Bob P.

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Petruska
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Robert...
In reply to rpenmanparker, Nov 9, 2012

I use most of the time Nikon's Capture NX2 as my RAW converter as I find it does a better job than PhotoShop.  In CNX2 I have it set to automatically convert any loaded file to sRGB no matter what the embedded color space is.  I also have PhotoShop set up to automatically do the same, convert to sRGB.  Thus the printer does it's best to output sRGB which we all know that it can't match 100% because of its limited gamut.

By using sRGB all the way through my workflow, I really don't even soft-proof anymore as there isn't much differences between my edit screen and soft-proof screen.  My prints match extremely well to the monitor for colors and brightness.

I really don't spend much time thinking about editing and printing anymore, It's just click, click, click -  1,2,3. I perform 95% of my editing in CNX2, usually addiing some contrast and sharpening, I rarely need to adjust any colors.  I also print mostly from CNX2 and sometimes PS, both prints from either app are identical and should be or something is set up wrong.

Bob P.

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rpenmanparker
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Re: Pro RGB...really?
In reply to alvie, Nov 9, 2012

Alvie, wish I could be more help, but here is the best I can tell you. My tutor has relocated to another city so that is out. You can repeat what I did originally. Look online at the HCP lineup of classes with special attention to output and color management. Then call the main number and ask for the email of the person who is teaching most of them. Worked for me.  Good luck.

Robert

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rpenmanparker
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Re: Robert...
In reply to Petruska, Nov 9, 2012

Petruska wrote:

I use most of the time Nikon's Capture NX2 as my RAW converter as I find it does a better job than PhotoShop. In CNX2 I have it set to automatically convert any loaded file to sRGB no matter what the embedded color space is. I also have PhotoShop set up to automatically do the same, convert to sRGB. Thus the printer does it's best to output sRGB which we all know that it can't match 100% because of its limited gamut.

By using sRGB all the way through my workflow, I really don't even soft-proof anymore as there isn't much differences between my edit screen and soft-proof screen. My prints match extremely well to the monitor for colors and brightness.

I really don't spend much time thinking about editing and printing anymore, It's just click, click, click - 1,2,3. I perform 95% of my editing in CNX2, usually addiing some contrast and sharpening, I rarely need to adjust any colors. I also print mostly from CNX2 and sometimes PS, both prints from either app are identical and should be or something is set up wrong.

Bob P.

That's what I'm talkin' about. Thanks for the straightforward advice.

Robert

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Scott Eaton
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myths about printer gamut range
In reply to alvie, Nov 9, 2012

One thing that has driven me nuts over the years is the exaggerated gamut range often referenced for printed out-put. Doesn't matter if it's dye or pigment based - there needs to about ten asterisks* posted behind any gamut plot for a printer.

The reason is that unlike displays printed media requires a *light source* for reference. The intensity and spectral slope of that light source has a direct amount on the shape and scale of the gamut plot referenced for printers.

Some years ago when I was preparing exhibition prints for a client we calculated how much LUX would be required at the surface of a print to equal the intensity of the light source built into the densitometer used to evaluate print color. Results were something on the order of 50% daylight sun at the equator. These light levels are totally absurd for conventional inside illumination levels for our prints and darn near make the common gamut spaces posted for printers work only in an abstract domain. Unless you intend to illuminate your prints outdoors or use six 400watt daylight halides 10 feet away reflective color spaces are much smaller in practical application.

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technoid
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Re: myths about printer gamut range
In reply to Scott Eaton, Nov 9, 2012

The illumination used by spectrophotometers and densitometers are very bright in order to take a low noise reading. They measure relative reflectivity and they can get a good reading with low reflectivity (D > 2.0) by using a bright light. It has nothing at all to do with printer gamuts or what light you view a print in.

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