Have I bought the wrong monitor profile package?

Hi Loe, i am ploughing through your document about CIE LAB, as an editing space, especially when I convert RGB to LAB temporarily I am familiar, but as a mathematical model I am learning something very helpful. But as i was reading I was wondering about a miracle?!!? Is the LAB space independent of your monitor space? What I was thinking, probably way off here, but it occured to me that if The RGB value of a given portion of my image read that there was a lot of say red, and this was not represented in the print, would analysing the LAB values in Photoshop reveal this or would they also show a saturated red on the screen, i know this is a dumb question. But humour me for the moment.

Best regards

Chris.

Chris,

I am not totally sure I understand your question, but I will try to shed some light on Lab.

First, Lab is a device independent color space (ie, model of human vision). Theoretically, it describes a color unambiguously, since it does not rely on a device. In a sense, it is an "absolute" color space. Since it is a pretty good (not perfect) model of human vision, it has a much wider color gamut than any monitor, printer, press or other output device. It would have to if it is a model of human vision.

All devices, ie, monitors, printers, presses, etc, are different. Even two "identical" monitors will be different due to age, manufacturing tolerances, ambient conditions, etc. So a device profile (ie, monitor profile, printer profile, press profile) is required to describe the boundaries of its color space and to nail down certain color values. The profile has either a lookup table or tone reproduction curves that relate a specific color, for example a bright red, to the reference color space (usually Lab or xyz).

When you bring a Lab color file into Photoshop, no profile is required, since the colors are already established in Lab, which is device independent. BUT, if your monitor profile is inaccurate, the colors will display inaccurately.

If you bring an Adobe RGB file into Photoshop, you need to tell PS that the file is Adobe RGB, otherwise it doesn't know what the red, green and blue coordinates represent. So you need the RGB numbers AND a color space to identify the precise colors. Photoshop keeps track of this in the background by relating everything to Lab.

There could be a number of reasons a red color does not reproduce in a print. First, it could be out of gamut (nor reproducible on that paper/ink/printer combination), you may have an inaccurate profile, your settings could be messed up, etc. Same with a monitor profile.

I use a program called ColorThink to view monitor and printer profiles in 3D. I can bring in a file and see if the colors all fit into a given printer profile (which describes the total color gamut of that printer/paper/ink combination). If not, then the profile has to MAKE the colors fit. This is the purpose of Relative Colorimetric or Perceptual rendering intents. They are different models that allow the source file to be represented in the final print.

So, looking at Lab numbers in PS will not tell you whether your file will reproduce a specific red. That is the purpose of soft proofing, which is good, but not perfect. But, as you now know, you need an accurate monitor profile and an accurate printer profile if the soft proof is to be close.

Hope that sheds some light on the subject.

Lou

Hallo Lou,Have just run a simple test keeping consistency with the same gloss paper that I have been using for last few weeks. I filled a 4x6 with two patches of near white and then compared them with the D50 and D65 Profile that I have stored on my computer.

the two patches were:
232 - 233 - 239 and
245 - 245 - 245

Both patches on my gloss paper are much less saturated than screen at D50 and better at D65.

I did this because i had a white swan and noticed that there was better white reproduction in the D65 (though there was indeed a subtle blue cast) than in the D50. (Same lighting as before). Problem was that although ALL my photos are better under The D50 profile, my two patches and the white swan are naturally much more accurate in the D65 profile. (Outside light is very very cloudy and late afternoon. Room is dim.

Can you explain these discrpencies in the near white reproduction. Obviously there is more yellow coming into the near whites at D50, yet I do not understand why my photos in general appear OK yet I have this difference, that means I would have to have different monitor profiles for viwing swans and other profiles for viwing landscapes. Yep I know this is totally absurd and would not do it, but you get my point),

Best regards

Chris.

Chris,

Do you have any color management experts living near you? You would probably benefit tremendously if someone could sit down with you for 3 or 4 hourse and get everything right on your system, make sure all your photoshop settings, printing and driver settings are correct, insure you have good monitor and printer profiles, etc. They would also discover and be able to explain what is going wrong, because something clearly is.

A lot of things could be happening, but without knowing all the variables, I'd be taking potshots. Too much time.

Do you have a recent, accurate, custom profile for the printer/paper/ink combination you are using, or are you using a canned profile? Do you have perfect nozzle checks? Are you sure you are using the right settings to print? If I were there, I could probably uncover the issues.

My two papers explain the entire process fairly thoroughly. If you have done everything I describe and still can't get a good match, then it is time to either study more or call in an expert.

Lou

Well Lou, you know, I searched long before I came on to the Adobe forum which is why I am here. There is nobody. All I can say is that I am using canned profiles from Canon Grrr and that all my colour settings do check out. I sent for customer help at Colour vision, they donot reply very well, I am still waiting for confirmation from tem to check that my setup was correct in the first place. But I am sure it is, I have been through it with a fine toothcomb. Printer is clean and nozzles are good. the test images are as near pefect as you can get, red on print little lighter than screen, greys check out so much better, yellows a little more saturated but heh, this is second grade professional paper from canon, I have not bothered opening the top grade yet. Blues are perfect. Shadow detail is so better. Just that little niggly point at what I wrote about my two patches.

But colour could not be better and overall appearance could not be better.

It was just that I had a white swan with light/yellowy brown dirt (light sand colour) on his neck and when I saw the screen, the white was not white (more a slight yellow tinge of white) and the dirt on the neck was/is yellowy brown, a deeper darker brown.

You know what, I have taken so much of your time, I want to thank you for all your help. Without your perseverence I would not have even thought to have tried out D50 based upon the absence of circumstantial parameters in my lighting environment. I appreciate all your advice, and will remeber your website. I am in Ireland so it seems difficult to come to you for profiles should I invest in hahnemuhl or pearl papers. i was even thinking of getting a proper profile for Canon's Pro paper before I used it, but only when I know that this issue is comfortably improved just a tat more.

Thankyou Lou

Kind Regards

Chris.

Ireland isn't very accessible from Alabama, you're right about that. I'm sure there are experts over your way too.

Canned Canon profiles are reasonably good if you are using their papers. But, this assumes YOUR printer is the same as the printer used to build the original profile. If it is the same, the profile will work the same. If you printer is a little different, your prints will be a little different. If you printer is a lot different from the standard, all bets are off. Properly built custom profiles are the best bet, but I understand why you are waiting.

Here's what I would do in your shoes. See if BasicColor or ColorEyes Display software is compatible with your colorimeter. If so, download the trial version of either one. They both do an excellent job and I had zero problems with downloads from either vendor. Then Calibrate your monitor using the following settings as a starting point....5500K, 2.2 gamma, 90 cd/m2 white luminance, 0.3 cd/m2 black luminance. Then compare monitor to print.

If your monitor is too warm, increase the temp to 5800K, if it is too cool, try 5200K. Keep adjusting until it is a good match. Since your viewing light source is a moving target, you will have to find a compromise that is close and splits the difference. I'd say 5500K is a great starting point. Then assess tonal range (black to white). If your monitor is brighter than the print, lower the white luminance to about 80 cd. If your monitor is darker than the print, try increasing it to 100 cd. You get the idea. You can try a different black point too, but I'd leave it at 0.3 cd.m2 until you get the other settings correct.

If that does the trick, then buy the new software and flush your current software down the commode. Good luck (and you are welcome).

Lou

Hi Lou, thanks so much for even that. I will look soonest. Yes the whites on the monitor are brighter than the paper, I did another test print of another file and achieved excellent results apart from gray and white. i must say that i did also tests by doing three seperate calibrations this evening under very subued lighting and I set the spyder to calibrate in three totally different ways including measuring ambient light and not measuring ambient light. I then viwed all three profiles unde the same light source and the same printed photo under the exact same light source, I should have had slightly different appearances from my monitor, but gues what, all three profiles were EXACTLY the same, and this proved to me that SPYDER3 PRO is a con.

The canon printer issue, yes I had read about that. But thanks for the web site links, i will look when I can.

In the meantime, the customer support at Spyder have not replied to my ticket, it was a lengthy ticket.

You do not have to reply to this, appreciate your help.

Chris in a wet Ireland in the middle of summer.

Chris,

As long as you are using the correct print settings and a decent profile, there is no need to reprint your photos for comparison after reprofiling your monitor. The monitor profile is totally independent, and changing monitor settings will have zero effect on the print. Both the monitor display and the print are derived from the numbers in your file and are parallel paths, one goes to the printer and another goes to the monitor. If the numbers in the file don't change, and you use the same printer/paper/ink and settings to print, you should get an identical print every time.

The monitor profile does only one thing....it adjusts the numbers in your file on the fly and displays them on your monitor. So you can use a single print to evaluate numerous monitor profile combinations of luminance and white point.

You probably knew that, but I wanted to make sure. It could save you a lot of paper, ink and time.

Lou