So I was asked the question by a commenter just how familiar I am with the G7 method, and just what I think of it.

Interesting question too. Because as it so happens, G7 has been on my mind a good deal of late.

You’ve probably seen G7 and heard of G7 and probably know that it’s got something somehow to do with this whole field of color management, but do you know what it is, where it came from and how it works?

Well, G7 was developed by Don Hutcheson of Hutch Color, who then–as I’m given to understand–handed over the rights for distribution and promotion and marketing to IDEAlliance.

The name G7 refers to Grey, plus the seven ISO standard colors, CMYKRGB.

So what’s it for and how does it work and what does it do?

Well, back before there were computers or digital images, there were was a move to make standard densities for ink on litho presses. The Holy Grail was and has been in some quarters to make it so that printing was simply a matter of conforming to standards, so that all printing everywhere could be exactly the same.

So all things being relatively equal, if two printers are using inks that conform to a standard, and printing to densities that conform to a standard, then their prints should match, right?

Well, not always.

It gets a little trickier, what with a phenomenon that used to be called “dot gain” but now goes by the more official sounding sobriquet of “Tone Value Increase” or TVI.

And each color on any litho press is going to have some sort of unique “TVI” curve. You can picture it something like this: If you’re not printing any of a color, then since you don’t have any dots, you’re not going to have any dot ga…er, tone value increase; and obviously you also won’t if you’re printing that color at 100%, because you haven’t got any dots to gai…er, tone values to increase in a solid; but where you do have dots, you’ll probably have the most TVI in the mid-range, where they have the most room to gain…er, your tone values have the most propensity to increase.

Anyway, you get the idea.

So if you’re following along here, what happens is that even though two presses might be using the exact same ink and printing to the exact same densities, since they have different TVI characteristics, the internal elements of a same image on the two presses might not be the same.

Okay, now I like to rail against standards a bit, but there are certainly instances when this is important. If you’re an ad agency and you’ve got a buy in several magazines, all you want is to approve the proof and have all the magazines print the ad exactly the same.

So lets fast forward a little to the present day, or at least to an ICC world, and now printed images start as files. And now there are ICC profiles that define the pixels in those files as they relate to the color spaces in which they were created, or to which they have been converted for whatever purpose.

And there are some standard spaces out there like SWOP and GRACol, and wouldn’t it be a wonderful world if all anyone had to do was just use whatever standard profile was called for by the final output, and that would be that, and wherever you printed your image, the standards would be met and it would be exactly the same.

Now here we’re still talking about litho. And at this point if you want to have a proper characterization you’ve got two real choices. You can profile your press and somehow or another convert your file to that particular profile before it prints, or you can calibrate (linearize) your press so that it will print with a standardized profile in an expected way.

And that’s what G7 does. G7 is press linearization, in essence. So that once the press is linearized, it should print files in standard color spaces exactly as expected.

In fact, the G7 manual doesn’t even really recommend you do an ICC profile of a press once you’re done with the G7 process. And if you think of it, why should you?

You know your process colors as defined by ISO standards, and your densities as well, so you know your total gamut is going to be exactly the same as your standard profile.

So G7 definitely has a place in this world…

But I’d argue that place isn’t large or grand format printing.

First reason is that if you’re using a correct and completely color managed workflow, G7 would be somewhat out of place and redundant to start with. There isn’t too much likelihood that your grand format UV machine is going to print correctly if you use SWOP or some other standard print space as its destination space. It’s a given that you’re going to have a custom profile for that machine on that media in the first place.

And it’s a given that you’re going to linearize that machine before you profile it. If you accomplish both those tasks well, the whole reason for the G7 method becomes a little moot.

Now, there are people out there who hold that if you use the G7 method to enhance your linearization you’ll get a linearization so true that profiles truly can be used from one linearization to another…but, that seems more like theory than practice to me. And it still doesn’t make a great deal of sense, since it’s going to take less time to just do a standard RIP-based linearization and then reprofile than to go through the entire G7 routine.

And that of course would be just using G7 to linearize. I’ve seen people touting the G7 process to large and grand format printers, and I do have to say that if that includes attempting to print to “standards”…well, I think that misses the point.

Large and grand format printing aren’t about printing magazines. Large and grand format printing are about big; about bold. About stopping someone on the street in their tracks with a visual and demanding their attention.

If you capture all the gamut your machine has to give in the profile-making process, you can always tell it to emulate a smaller-gamut device if need be for those times when standard colors across a campaign are important.

Let’s say you inhibit your half-a million dollar machine via ink limits so that in the name of standards it can only print the gamut of a web press, can you now use SWOP as its print space?

No. Because it’s not a web press. You still have to do the conversion to your machine space. And what you’ll get is a print that–assuming a well-done profiling job–is a good match to a SWOP proof. However, if your machine is profiled to give you every bit of color it’s got to give, and you send it that same SWOP file, what will you get?

An image you can lay side by side with the other one and it will be identical.

Myself, if I paid a quarter to a half a million dollars for a machine that can print three times the color gamut of a web press, I’m not about to throw all that capability away in the name of “standards.”

Don’t get me wrong here. I think the G7 method is ingenious, and a very elegant way to solve a very old problem. And in solving that problem I’d recommend it above just about any other solution.

It’s just that to me that does not make it one size fits all, or the absolute be-all and end-all of printing device characterization, as many of the people out there hawking it might suggest.