Gamutvision etc.

[Roy Sletcher]

As the Chinese proverb says: The first step towards progress is calling things by their proper name.

The statement below confuses the differences between color models (RGB/CMYK,CIELAB) and gamuts!
Adobe RGB(1998) and sRGB are both RGB color spaces (specifically Working Spaces), they have differing color gamuts

"RGB color space or RGB color system, constructs all the colors from the combination of the Red, Green and Blue colors.

The red, green and blue use 8 bits each, which have integer values from 0 to 255. This makes 256*256*256=16777216 possible colors."

Estimates on the number of colors perceived by human vision are ~10,000,000 colors. Some have guestimated the top end at ~7,000,000.

So, the Eizo displaying 98% of ~16,000,000 possible colors still far exceeds the capabilities of our eyes (and some of our wallets).

Forget this notion about millions of colors. You can't see anything like that number, and if you can't see them, they are certainly not colors.
It's marketing hype.

What you may be alluding to is:
Adobe RGB (1998) and sRGB, ProPhoto RGB are just color spaces, or rather containers. They don't inherently have any information other than specifications for primaries, white point, and gamma. Until we actually have a pixel, they don’t contain any information. The pixel has an encoding value which can provide a number of possible device values. For example, 24 bit color, (three channels, 8-bit each) can mathematically define 16.7 million device values.

The point is, we can use math to produce a value that has no actual relationship to what we can see and call color. Our computers do not manipulate colour, or even have any colour sense. They merely crunch the numbers, that can be converted to colour values depending on the colour model and space or gamut being used.

All the RGB working spaces have exactly the same number of addressable device values and the total number is set by the bit depth of the image file used for encoding, i.e., 8-bit, 16-bit. It is important to note that AdobeRGB has a much larger colour gamut than sRGB, even though it contains EXACTLY THE SAME NUMBER of addressable spaces which is the magical 16.7 million previously mentioned, if encoded in 8 bit.

In a nutshell: The millions of colors are encoding of device values, NOT colors.

Sorry to be such a pain. Please re-read my first sentence.

RS

 

[stratman]

In a nutshell: The millions of colors are encoding of device values, NOT colors.

What do you think the light perceived by your retina is conveyed as it travels within the optic nerve on its way to the visual cortex in the occipital lobes? It's not colors but chemicals and electricity carrying the code that is decoded in the brain as colors.

The numbers of potential colors distinguishable by the human eye can be as many as 10 million depending on the source you choose to accept. Same for the mathematical count for 8 bit color from those dealing with computers.

I was going to link to other web pages that specifically discusses the paradigm of containers, such as this, and issues you touched upon, but that was not my purpose. Regardless, this does not negate what I did post, which was to demonstrate the large gamut of the Eizo monitor compared to human vision as well as to expand slightly on your comment about Adobe RGB gamut versus human vision.

Adobe RGB and sRGB have different uses for different purposes, especially for those limited in color management software, skills or desire.

In my second post I provided a link to demonstrate the differences between the Adobe RGB and sRGB as well as their further limitations when compared to the monitor and human vision.

And then there is this little gem from Ken Rockwell who poo-poo's the Adobe RGB color space.

I guess this is a long winded way of saying I use these features when prepping and soft proofing my images, comparing profiles, and generally trying to improve my prints.

Does it help - I like to think so, but cannot give an empirical answer.

You may actually have given an empirical answer in these two sentences, just not the answer you expected at this moment.

 

[3dogs]

This is starting to move in a direction I can follow having read the Canyon Conundrum over and over I am an advocate for free colour, bit like free verse poetry, just not constrained by dogma.

That is why this software is SO appealing.
We dial in a colour space at camera, mirror that in the computer then print to a device that lays down a medium that is batch formulated and changes over time.

How does one keep this flock in one place,
Seems to be like holding a handfull of worms inside two hands.

RS you are spot on when you say to find a need first

Step before that, for me is to get a better handle on colour and what Eizo mean by rgb
Remembering that Eizo are MARKETERS, 98% of RGB could, and probably does mean anything

 

[Emulator]

If you are interested in the detail there is little better than DispcalGUI used to calibrate your display. Images below illustrate only some, about half, of the information you find. First image sRGB, second image AdobeRGB 1998, showing the result of profiling my own display.

I am inclined toward Rockwell's views on the use of Adobe RGB disrupting the colour spread in subsequent processing, particularly when you can't see it or your display cannot display it and your printer can't print it. I use RAW and AdobeRGB in the camera and I have pondered the question of converting to sRGB in Adobe, before processing the image, or after processing the image and before printing, or switching the camera to sRGB.

 

[The Hat]

Keep it going guys, because this is getting very interesting, expanding... !

 

[3dogs]

If you are interested in the detail there is little better than DispcalGUI used to calibrate your display. Images below illustrate only some, about half, of the information you find. First image sRGB, second image AdobeRGB 1998, showing the result of profiling my own display.

I am inclined toward Rockwell's views on the use of Adobe RGB disrupting the colour spread in subsequent processing, particularly when you can't see it or your display cannot display it and your printer can't print it. I use RAW and AdobeRGB in the camera and I have pondered the question of converting to sRGB in Adobe, before processing the image, or after processing the image and before printing, or switching the camera to sRGB.

View attachment 2885
View attachment 2886

I am so glad @stratman posted as he is zoning in on the core of this thread by introducing issues at the very foundation of the process of colour visualisation and representation.

From as early as I can remember I saw colour, it was meaningless in that I just accepted that was how things ARE. As time passed and I developed a vocabulary and began to communicate and think, the things around me needed labels. So, as we are so heavily dependant on sight and communicating labels for colour become important.......
Try this sit down and write the names of all the colours you have labels for.........16 million names on your list? Yet colour is a crucial part of verbal communication and as many visual tricks demonstrate we are not very good at seeing what we are looking at.

I am not sure that the mode of transport used to move colour information is super critical, but I do know that the Chemical electrical is easily foiled. That leaves us with numeric and/or spacial.

Thus for reproduction colour as in Monitors, books, magazines and pictures of all kinds, a numeric value system is invaluable. It delivers a standard. However, that is all it does because each person (or so I believe) sees a known value differently depending on their own unique wiring......that thought process leads me to conclude that how we see is a significant input on personal preferences in the visual arena.

Further, I believe like those colorspace multidimensional maps show where numeric colour values are common to different colour spaces, so the human brain has many areas of common perception that we all share. I believe that if we could map what colours each of us sees and likes we would have large areas in common and also large areas of difference.

For this reason I feel it would be very interesting to dwell for a time on the colour space question before proceeding further with Gamutvision etc.
If I remember correctly @TheHat put to the forum some time ago that for printing it seems that we reverse process in that we select a colour space based on what we read and feel comfortable with, then get all the downstream workflow to conform to that and then send the information to a printer that has no hope at all of printing what we see.
That was not quite how he put it in his post but that was what I took from his comment, and it made sense.

Reverting to Gamutvision for a moment for me that raises a very important question:
Will a Gamutvision like product tell me what colour values my Canon will print with OEM dye ink, and what colours the 3880 will print with Cone inks thereby enabling me to narrowing the gap between the output of the two machines.
In other words can I use Gamutvision to analyse the output of each then do something about helping them to print known colours the same?

I am thinking that I may just switch to sRGB and see what happens. I shoot RAW so its all the downstream settings that will change.

 

[Ink stained Fingers]

You are raising a question
'Will a Gamutvision like product tell me what colour values my Canon will print with OEM dye ink, and what colours the 3880 will print with Cone inks thereby enabling me to narrowing the gap between the output of the two machines.'

Let me show you what can be shown with such a Gamutvision like product, I'm using a version of Gamutworks of the discontinued Monaco Profiler suite by XRite which as well has various display options:

I'm using a sample image Monaco 1 as displayed in the left part of the program window


I'm changing the view, the program shows in the right window the 3-dimensional plot of all colors
in this image in the Lab color space as dots and dot clouds


and the program can display those colors with a particular lightness, in this case L=21(%)

I'm adding an ICC printer/paper profile to the display, for a HP paper on a R265, this profile shows up
as a kind of double cone , all colors within this volume can print as they are, and all colors outside cannot be printed as such, they need to get some correction, typically a reduction of the color saturation.
A hoizontal cut through the lower part of the profile cone is shown in the most right window at the
selected lightness level



You can see image colors as dots within this profile outline, and dots outside, those colors outside the
gamut of this paper

When I go to the lighter part of the profile - L=94, just a % below the white level of the paper, you
see the profile outline, rather small, and lots of image colors outside as well.

You can create such profile now as well for another ink set, or another paper, or using other driver
settings and create with a profiling program another icm-profile, and display that 2nd profile together
with the first profile and see which one has more volume, which one extends more into a particular
color region, you directly can compare profiles from different inks or papers.

You are raising a 2nd question

'In other words can I use Gamutvision to analyse the output of each then do something about helping them to print known colours the same?'

Yes, Gamutvision and alike will let you compare profiles, their size, their width, the color ranges they
cover, and such programs will show you as well which parts of an image are out of gamut, somewhat
impeded in their color reproduction.

icm-profiles are effectively correction tables which counteract the incorrect/shifted colors of a printer
as it prints without such profiles, so profiles take care of that, actually the software you are using to
create the printouts in connection with such profiles activated in this software.

There is probably a question left - what happens with those colors 'out of gamut'? They cannot be left out totally, that would look quite funny, depending of the type of image there are various options called
rendering intent. There are some different approaches possible - colors out of gamut are mapped to the closest color on the boundary of the gamut cone, or you can reduce the overall color saturation until all colors fit into the gamut, or when you create an image, e.g. a poster you try to avoid out of gamut colors alltogether from the beginning, it all depends

Gamuvision and alike are programs to visualize profile and color properties in connection with color transformations, Gamuvision itself does not create icm-profiles, there are other threads running on ColorMunki, Spyder etc for this purpose

 

[RogerB]

Just back from a three-day break with no internet so missed the early stages of this thread. FWIW here's why I use (and like) Gamutvision.

Whenever I generate a profile the first thing I do is load it up in GV and evaluate it. The steps that I use have been discussed in other threads. If I am satisfied with the evaluation I then print a standard test image for a visual evaluation. My test image includes a control strip with the ColorChecker-24 colours. I can compare that directly with a reference strip; I don't expect to be able to see any difference. That's it for profiles I make for myself or profiles that I make for others on-site.

The real value is when I make profiles for others using charts that have been posted to me. The only evaluation I can do then is using GV - no possibility of a test print. From a GV evaluation I can usually tell if the charts (2x A4) have been printed correctly or if the printer has some fundamental problems. The majority of remote profiling I do is for third-party ink/paper combinations; these usually have smaller colour gamut, poorer colour accuracy and worse greyscale rendering than OEM systems. All of these attributes are evident from the profile, and I can give the customer a brief synopsis of the performance of their printer/ink/paper combination.

I also print for others and often use the facilities in GV to compare the colours in the image with the printer colour gamut, especially when printing on matte papers. @Ink stained Fingers post above gives a good idea of how this works in Gamutworks - I think GV possibly does a bit more. When printing for others it is essential that the colours in the print are as close as possible to the colours in the file. This is why I am very particular about the colour accuracy of my own profiles, and what rendering intent gives the best result. GV helps me get it right without having to make test prints - test prints cost money and time!

Does any of this help people like @3dogs? I really don't know. However, picking up on a question from @3dogs, if your 3880 and your Canon are not giving good colour agreement then maybe you need to do something about your profiles. When I do a profile for someone on-site I run a test print with the CC24 colours and compare it with my reference. I usually get a very close match, no matter what the printer is, to the reference which is printed on my 3880.

 

[Ink stained Fingers]

yes, Gamutvision gives more functionality than Monaco Gamutworks and requires some more understanding of color processing, input devices - output devices - profile connection space , the meaning of various tables in the icm-profile, and some more. I use Gamutworks since it is still on my system, but it is part of a discontinued profiling package and not available as a stand alone program, and it shows particular profile/image details quite well, and some more than explained above. I'm doing my own profiles but only infrequently for others. I think the essence of all is that there is no reliable way to print colors correctly without the standardized profiling process, with a profiling software package and support software for validation like Gamutvision

 

[3dogs]

Thank you both for your posts, they are complimentary and comprehensively answer my question. In fact you have done a lot more and advanced my understanding of what i am doing when I profile my printer and screen. With a deeper appreciation of the process it seems pretty obvious that folks like myself that do generate profiles do so somewhat blindly........without analytical tools one operates on faith when it comes to making adjustments, or so I was suspecting, hence my initial question

Many, many thanks for expanding my horizons fellas, much appreciated and a valuable resource for others delving into this forum.

@stratman pointed out that Eizo recomend repeat profile generation, I recalibrate monthly, and have profiles for three ambient light conditions because my work area is subject to extremes, glaring full sun, dull overcast flat and my prefered condition controlled light. My output LOOKS ok so it must be right was a position I was not at ease with although in all honesty I had no idea how to validate a profile, screen or print......now I do!!