yet ANOTHER thread about profiles

Hello folks.
I've read, and read, and read about profiles and still don't know any more than when I started. The reason is that there is one very basic question that's always in the back of my mind and seems to keep me from "getting" what I'm reading: What's the correlation between monitor profiles and printer profiles? (It seems that the answer is "There isn't one.")
The subject of profiles usually comes up in the context of "how to make your prints match your monitor." So it seems that there would be some sort of "if-then"; like, "If you use this monitor profile, then you would use this printer profile." But in DPP (for instance) you can choose any monitor profile you like, and any printer profile you like, and there's apparently no connection between them at all.
I can understand color spaces, especially regarding photos for the web, because I read, "Most people's monitors/browsers are set up for sRGB, so that's what you should use." So there's a connection between my color space and others' color space. And I understand that you can download color profiles for your printer for certain types of papers, and again there's a correlation there between 2 things, the printer and the paper. But if there's not a connection between your monitor profile and your printer profile, I don't see how profiles can make them match.
Maybe my big question should be, "What the heck do profiles DO?" Everything I've read says something like "ICC profiles are files containing color information... Devices such as printers and monitors can be closely matched by using color profiles... You can print an image and simulate the onscreen colors by using a profile..." (Note that there's no actual how-to or why information in those statements!) The document in question will then go on to say something like, "So choose a profile..." Which one? Why? How? DPP offers me 10 profiles that match my printer model plus 10 others.
Well, I can see that I could continue this post for another hour because I keep coming up with new questions, and this is what happens whenever I read something like René's (really long!) thread on color profiles.
So if I could get some answers to these basic questions, I think I could actually get somewhere:
1) What's the connection between monitor profiles and printer profiles?
2) What does a profile actually DO? HOW will it help match the output of a monitor with a printer?
3) When an app like DPP offers me 20 printer profiles and 30 monitor profiles (and none of those profiles contains the model # of my monitor) how do I know which one to choose?

Thanks very much.

1) There isn't a direct connection. One profile describes the characteristics of your monitor, the other describes the characteristics of you printer. The monitor profile is used to let you see the image on-screen with accurate colours, and the printer profile is used to let you print the image with accurate colours.

2) A device profile describes how that device reproduces colour. 'Real world' colours are generally described by esoteric methods such as Lab (one luminence and 2 colour values) or xyz. The RGB values used in graphics processing do not, by themselves, determine a specific colour. To do that, you need to know how to interpret those R, G and B numbers - i.e. what real world colour does that combination of RGB values represent. That is what a profile is - a method of translating between RGB and (real world) Lab colours.
Now there are 2 kinds of profile - a working colour space (e.g. sRGB or AdobeRGB), or a device profile. The working profile is used for image files, so we know what real world colour everything is supposed to be.
Device profiles are a little different. What they contain is the answer to the following question:
"For any given set of RGB values, what real world colour does the device produce""
If you know the answer to that question, then you can do things in reverse:
"What RGB values do I need to send to the device so that it shows the exact colour I want?"
Therefore, device profiles allow an application such as Photoshop to modify the colours it sends to the monitor, or the printer, so that the device ends up showing the correct colours.

3) Printer profiles describe the colour characteristics of a specific printer printing on a specific paper. When printing, therefore, choose the profile for your printer and for the paper you are using.
Monitor profiles describe the characteristics of a specific monitor. When you calibrate your monitor, a profile is produced for it. This is the one you choose in DPP - anything else would make no sense. If you don't have a profile for your monitor, then you need to calibrate it to produce one!

If you really want to know more about this, I'd highly recommend the book "Real World Colour Management" by Bruce Fraser and co.

DPP offers you a lot of profiles you would do well to ignore. Its only the current monitor profile and the various paper/printer profiles that you need to use. The reason you see many others is because the operating system lumps ALL the profiles it knows into just one file, for it's convenience not yours!

Choosing a printer/paper profile is simple. Your printer driver has a set of own brand paper profiles listed, so select the right profile that matches the paper you want to use to that printer. Some of the names of the profiles may be confusing, if so just keep a note somewhere of what's what.

I'd go further than Graeme, I'd say there is NO connection between monitor profiles and paper/printer profiles. The monitor profile modifies the screen colours to the "standard" colours they should be by telling the monitor to show a set of standardised colour swatches which it promptly measures, then electronically tutts and raises its eyebrows before creating an adjustment table - better known as the ICC profile.

A good monitor profiling programme will also guide the user in setting the screen brightness/contrast, colour temperature and gamma, plus offer advise on what is considered "best practise" for each of these.

Points for clarity -- when you hear the monitor profile used together with printing, it is because the best way of approaching a print that closely matches what you see on screen is by having a calibrated monitor (this produces that profile that is tailored to your specific monitor) and using software that is "color managed" -- that is it makes use of that monitor profile, and then using the printer profile if possible in the application to "soft proof" you image and adjust it to match what the printer output would be, and then to use the application to manage the printer colors rather than letting the printer do it automatically. When these things are in place and working properly then you should see the two match.

So, the monitor profile and the printer profile are two separate things but are both part of a color-managed workflow that affect what you see on the screen (the monitor profile) and then extend to the prints, where the app uses the printer profile to manage the color and match it to the accurate monitor display.

If you get images printed the best thing to do is to try to calibrate your monitor so that it looks as close to the colors and brightness of the pictures when they are printed. Have some pictures printed from each of your labs. When you get them back bring up the digital images on your monitor and try to make the images on your monitor look like the prints. Save a monitor profile for each lab if they are different.

One of the main points of confusion that I see is that people often go to great lengths to calibrate their monitors but have no idea what they are calibrating them to.

If you don't print but just use images for viewing on your monitor or on the web the a standard calibration is great. If you are printing to something then your monitor needs to be calibrated to that, whatever it may be. Some printers will provide you with profiles that are calibrated to their output devices, but if your monitor is not also calibrated to that device you may see something different on your monitor to that what you get printed.

Okay, I have more questions, but I think I feel a really big AHA! coming on, so let me just see if I understand something:

Color profiles don't really "match your prints to your screen output" as is commonly said. All they do is let you get the colors you want (out of whichever device). Whether or not your prints match your screen is just something you decide for yourself, totally subjectively. Correct?

Your image is in a "working" color space - sRGB, Adobe RGB or another. Each color in the image is represented by a set of three numbers and the space determines exactly what color those numbers refer to. 245/0/0 is red, but it is a different shade of red in different spaces. The "working" spaces are mathematical models and therefore universal and independent of real world conditions, but devices have their own unique spaces which are determined by their physical characteristics. So lets say I have an sRGB image with 245/0/0 red in it. Lets call that Red 1. If that number is sent to my monitor, which has its own space that is different from sRGB, the red I see is a different shade. In order for me to see Red 1 the photo program has to know just how the monitor handles colors (its profile, obtained by measuring [mistakenly called "calibrating"] the monitor) and to change the 245/0/0 to that number which will cause the monitor to display Red 1. Now I print the image. If the computer sends 245/0/0 to the printer that will not produce Red 1 on the paper, again because the printer/paper combo has a space that is different and unique. Once again the program has to change the 245/0/0 to whatever number will cause the printer to print Red 1.

Through two separate and independent operations I have ended up with Red 1 on my screen and Red 1 on my paper. Monitor and print match.

jdouglas003 wrote in post #10367618
If you get images printed the best thing to do is to try to calibrate your monitor so that it looks as close to the colors and brightness of the pictures when they are printed. Have some pictures printed from each of your labs. When you get them back bring up the digital images on your monitor and try to make the images on your monitor look like the prints. Save a monitor profile for each lab if they are different.

One of the main points of confusion that I see is that people often go to great lengths to calibrate their monitors but have no idea what they are calibrating them to.

If you don't print but just use images for viewing on your monitor or on the web the a standard calibration is great. If you are printing to something then your monitor needs to be calibrated to that, whatever it may be. Some printers will provide you with profiles that are calibrated to their output devices, but if your monitor is not also calibrated to that device you may see something different on your monitor to that what you get printed.

That is like saying that if I like vanilla ice-cream and my wife likes chocolate, if I pour brown shoe polish over my ice-cream we will experience the illusory joys of togetherness. The only problems will occur when I give my many mistresses a share of my ice-cream.

tzalman wrote in post #10371093
That is like saying that if I like vanilla ice-cream and my wife likes chocolate, if I pour brown shoe polish over my ice-cream we will experience the illusory joys of togetherness. The only problems will occur when I give my many mistresses a share of my ice-cream.

Heh! I don't even want to imagine -- "Run for the shelter, Elie!"

tzalman wrote in post #10371046
Your image is in a "working" color space - sRGB, Adobe RGB or another. Each color in the image is represented by a set of three numbers and the space determines exactly what color those numbers refer to. 245/0/0 is red, but it is a different shade of red in different spaces. The "working" spaces are mathematical models and therefore universal and independent of real world conditions, but devices have their own unique spaces which are determined by their physical characteristics. So lets say I have an sRGB image with 245/0/0 red in it. Lets call that Red 1. If that number is sent to my monitor, which has its own space that is different from sRGB, the red I see is a different shade. In order for me to see Red 1 the photo program has to know just how the monitor handles colors (its profile, obtained by measuring [mistakenly called "calibrating"] the monitor) and to change the 245/0/0 to that number which will cause the monitor to display Red 1. Now I print the image. If the computer sends 245/0/0 to the printer that will not produce Red 1 on the paper, again because the printer/paper combo has a space that is different and unique. Once again the program has to change the 245/0/0 to whatever number will cause the printer to print Red 1.

Through two separate and independent operations I have ended up with Red 1 on my screen and Red 1 on my paper. Monitor and print match.

Excellent explanation, thanks.
So it sounds to me like my AHA...
Color profiles don't really "match your prints to your screen output" as is commonly said. All they do is let you get the colors you want (out of whichever device). Whether or not your prints match your screen is just something you decide for yourself, totally subjectively.
...was correct.
Stay tuned for further questions.

"Color profiles don't really "match your prints to your screen output" as is commonly said. All they do is let you get the colors you want (out of whichever device). Whether or not your prints match your screen is just something you decide for yourself, totally subjectively".

I would not describe it like that. The monitor profile makes the monitor display colours "correctly" to a pre-agreed standard. The printer/paper profile does the same for its side of the colour management. These may, or may not, be what you or I want, however what we see is what we will get.

Hi ncjohn...I´d like to say first that I´m no expert infact I am a complete beginner. Two weeks ago I was in the same place you are, I wanted to print my photos but was very confused by what I was reading about color spaces and profiles. But i found in practice it´s quite straight foreword and easy to understand,so I hope my experience will help you.
Here´s what you´ll need,
A monitor, mine is a samsung 2333hd
a calabration device, I got the Spyder 3 pro
Editing software that handles color management, I use canon DPP and the Gimp
a printer, mine´s a pixma ip4700
and paper.
The first think to do is calibrate your monitor,and this is where I was confused I didn´t know that when you calibrate it gives you a monitor profile,So now you have a monitor profile for your monitor. The next thing is to Choose a paper and find a print profile,there´s two places to look your printer should come with profiles for different papers or the paper manufacturer should have profiles for you printer to download.First I tried Ilford galerie classic gloss but found that there´s no profiles for this paper and the Pixma ip4700, so i changed to canon photo paper pro II this profile came with the printers software. The next thing you need is your image file and your editing software working in the same color space, I use Adobe RGB if you use The Gimp like me then you will have to downlaod this profile from there website. Now all you have to do is put all the profiles in the right place in what ever software you are useing and that´s it your prints should match what you see on you monitor,more or less a screen is not the same as a bit of paper. With these three profiles you can then Soft proof before you print, it will give you a better idea on screen of how your print will look with what ever paper you are useing. Well I hope what I found helps ,I also hope it´s correct I think so it seems to work for me.

Be aware that due to the differences between reflected light from a print and the backlit monitor display, even with accurate profiles in a colour managed work flow there will be slight differences.

Lowner wrote in post #10372681
"Color profiles don't really "match your prints to your screen output" as is commonly said. All they do is let you get the colors you want (out of whichever device). Whether or not your prints match your screen is just something you decide for yourself, totally subjectively".

I would not describe it like that. The monitor profile makes the monitor display colours "correctly" to a pre-agreed standard. The printer/paper profile does the same for its side of the colour management. These may, or may not, be what you or I want, however what we see is what we will get.

At some point, do we have to "eyeball" the output from one device and decide whether or not it matches the output from the other device? (And then tweak something if it doesn't?)

ncjohn wrote in post #10375383
At some point, do we have to "eyeball" the output from one device and decide whether or not it matches the output from the other device? (And then tweak something if it doesn't?)

Sure, just realizing that some variations are not abnormal. It's like saving something for the Web and comparing it using an uncolormanaged browser in a sense, although with an app like Photoshop you have "softproofing", where in your Proof preview you can set it to view an approximation using the printer profile. So, depending on the monitor, the monitor profile, the printer and the printer profile you may see some discrepancy that you want to adjust for -- in fact, some people actually create a Photoshop action that they apply to an image to compensate for a common discrepancy, similar to how they apply a specific type of sharpening, to an image that is ready to be printed, whereas taking a different path toward preparing in image for the Web.