So we all know what an ICC profile is, right? (In this case, ICC printer profiles.)

Well, I like to think of ICC profiles as roadmaps. That’s one my training session analogies. You put them in the glovebox and they’re there whenever any application needs to call on them to get to their particular color destination.

So how are they created?

“Oh! Oh! Oh! Iknow! I know! I knoooooowwwww!…”

Yeah, I see you jumping up and down and waving your hand around. So okay, go ahead and answer.

“Well, you print up some patches, and then you get your iOne, and you look all cool while everyone walks by and asks what you’re doing because you’re a color guru now, and you read the patches into Eye-One Match and when it’s done you’ve got yourself one first-class ICC profile.”

Okay, thank you. What about creating the state of the machine?

“Huh?”

You know, creating the state of the machine. That profile you just made measured something, didn’t it? It measured color values that machine produced on the media you put through it in exactly the state it was in when you made it.

“Ohhhhhhhh…you mean like ink limits and stuff?”

Yeah, ink limits and stuff.

“Oh, well, um….”

Okay, you get the point.

Here’s the bit of it: What’s absolutely unfortunate about the ICC profile making process is that a profile doesn’t have to be a good profile to be a valid profile. You can make yourself a pretty crummy profile with some pretty crummy software and some pretty lousy parameters for the machine (or you can download yourself a crummy profile) and it’ll feed your $250,000.00 printer that crummy information just as if it was prime beef.

See, making the profile is the easy part. Creating the state of the machine, that’s what matters. The “state of the machine” is the entirety of conditions you’re characterizing when you make an ICC profile. And the profile can tell you a lot about itself before you even use it to drive a printer, if you just know where to look.

So, here’s the procedure I use to evaluate every profile I make:

First step is to open the profile in a 3D gamut viewer. I use Monaco GamutWorks, but there are others out there as well.

You’re looking for several things in a gamut viewer. First, you’re looking for the overall size of the gamut. It’s going to vary from madia to media and machine to machine, obviously; but each machine and inkset has a basic “footprint” that becomes pretty easy to recognize after a profile or two, and the gamut needs to look like it’s getting all the machine has to give for the situation that’s being profiled.

Here’s a nice gamut of a large-gamut printer. In this case an Epson 3880. It’s smooth and well-formed, large, and produces color all the way down to its maximum density.

You can see that in the area circled in red. The point along the white line is black, and extending beyond it is the profile’s ability to make color at full density. To get full, rich color throughout the gamut of a machine, this is absolutely crucial. Regardless of where maximum density winds up in any profile, it should not come down to a single black point. The machine should be able to produce color right up to maximum density. And it’s the profile’s job to allow it to do it.

And that is a function of the inter-relationship between single channel ink limits and multi-channel ink limits–the state of the machine.

I’ve come to think of it as the point of precise maximum inking when creating single channel limits. The ideal is to balance the max on each channel exactly so that you’re getting the maximum out of each channel without the combination of any of them putting down too much ink too soon; making the machine reach maximum saturation prematurely so that it will then not be capable of printing full, deep, rich colors.

Assuming the profile looks good in 3D, I then import it into my ColorSync library and view my standard demonstration image through it in Photoshop soft proof. I’m not going to show you all my demo image here, but this is a part of it.

First image is a screen capture of the image with no soft proof applied. Second is the image with the above profile applied as a soft proof.

The area in the upper left is the image I’d use to check every profile I make if I could only use one image to do it. To those who don’t know, it’s called the Granger Rainbow; it’s relatively easy to make in Photoshop, and there’s nowhere in it for flaws in a profile to hide. Note that here it has shifted–obviously–but there’s no posterization, no untoward artifacts; and in particular, in the area circled at the bottom, there are very good transitions all the way across to black, confirming what the 3D visualization showed.

Note also the the Color Checker looks good, the color swatches and ramps look good, and the gray ramps distinguish all the way down to black, and are nice and neutral from L* 0 to 100.

That all done I load the profile in place on the client’s machine and print a test print. If it matches what I see on the screen, then it’s a keeper.

Now here’s another a 3D plot of another profile.

You might be surprised how many profiles there are out there that look an awful lot like this under the hood. Note that in this profile the black comes down to a severe point, which means the machine has no ability to print full colors except in what appear as the outer areas of the profile where it can print to its single channel limits without overinking. This is what happens when single channel ink limits are set too high in relation to the point of precise maximum inking.

Oh, oh, oh….wait. Yeah, I hear you. “Hey! Don’t be talking to me about single channel limits,” I hear you saying. “I am the single channel master. Got my technique down and everything. My single channels don’t be hookin’ or nothing.”

Well that’s all well and good but it’s also beside the point. Each of your single channel limits can be just fine on their own, but the combination of all of them can still cause this effect.

Want even more fun? Here’s what the profile looks like in soft proof.

You can see in the Granger Rainbow exact confirmation of the 3D. Instead of making full rich color all the way to black, this profile runs to black way, way too early. But…

Suppose you weren’t using the Granger Rainbow. Suppose you just had the other elements here on the screen? Color Checker looks good. Patches look good. Ramps look good, including the black. Even the spectrum in the Correct Color logo looks fine. But you go trying to print images with deep rich shadow tones in them, and this profile will let you down every time.

Trust me, there are lots of profiles like this out there. Odds are you’re using some now. (If you’re running a Roland, odds are double.)

Of course if I made this one I wouldn’t do a print test with it. If it fails here it’s going to fail on the printer. Time at this point to scrap it and start over.

Want to have some fun?

Here’s a nice big Granger Rainbow you can download.

Fee free to use it to check out your own profiles and see what you get.