Archive for August, 2009


RGB CMYK, what does GM have to do with it?

August 25, 2009

I miss the Canon TechNET Conferences. Canon use to hold them in Florida and California every year in August.  Yes it was Hot, Damn Hot to be in Florida in August but they were a great learning experience. i even took my young family to Disneyland a couple of times. But It was a working trip for me. It was where I learned much of my trade in a real world sense. IMHO there was no better technical training for an SE. The scope and depth of what you could get exposed to in a few days was unparalleled. From theory to hands on workshops I have never experienced a better run technical conference.

When Canon started doing the TechNET conferences EFI provided much of the technical expertize. But by the time they finished running them (thanks Arnold) Canon was doing most of the technical presentaions themselves, and doing a fine job. They use to do technology “primers” the first day. Stuff that was considered too basic for the experienced SE, but very, very important to those who were starting out.I personally attended these for the first few times I attended TechNET (I felt it was worth my time)

When it comes to color management, and color theory, especially on how it applies to the real world I will always remebr a phrase that I learned at one of my first Canon TechNET primers:

“Red Car BY GM”

What the heck does General Motors (GM) have to do with color management? Nothing, but if you remember that phrase and if you know how to draw triangles you will understand the relationship between RGB (Monitor) color and CMYK (Printed) color.

RGB (Monitor) color is represented by this first triangle

RGBCMY (we’ll talk about K later) is represented by this second triangle

CMYThe relationship between RGB and CMY is best described by

Red Car BY GM

Red Car BY GMThe relationship is R (red) to C (cyan), B (blue) to Y (yellow), and G (green) to M (magenta). Hence Red Car BY GM. When you draw your first triangle simply put an R, a G, and a B at separate points of the triangle. Now draw an inverse triangle so that is forms what looks like a star (or a star of David). And put the C (Cyan) opposite of the R (red), and the Y (yellow) opposite of the B (Blue), and the M (magenta) opposite of the G (green). So that your Color Star looks like the one above.

Now we can talk about the relationship between what we see on a Computer monitor (RGB) and what we see on a printer page (CMYK). The colors on each side of a color are directly proportionate. The Colors across from each other are inversely proportionate. What does that mean? Well if  the Graphic Artist says I want this to be more RED, most people will increase the Magenta because they think Magenta is directly proportionate to Red. But you only have it half right. Red is made up of Magenta AND YELLOW equally. since M & Y are on either side of R they are directly proportionate. So if I want more RED, I could increase BOTH my Magenta and Yellow. But I also could do something else. I could decrease my C (Cyan). Since C is across from R, they are inversely proportionate! I can reduce Cyan to shift the print to more Red. I still use this today, in fact I did use this today to help minimize a green hue in what the customer wanted to be a neutral tan.

So what about the “K” in the CMYK. What the heck is K anyway, and why doesn’t “K” show up in the triangles. . K = Black. And The triangles are theory. If you have R=0, G=0, B=0 you have black. And , in Theory if you were to mix equal portions of CMY together you would have Black at least at the maximum densities, at least in theory. in practice (read the real world) you most often get a muddy brown. So they add K or Black so that they can get a real, true black without mixing CMY.

Now this does not address a “cool black” or a “warm black” or a Pantone black versus an RGB Black vs a CMYK Black, And you thought that black was just black. Just for fun take Quark Express, or Indesign a draw a number of boxes and put each of the a fore mentioned blacks in them. Then print them out on your preferred MFD or high end printer and notice just how different they look. (Full disclosure: this was a Canon TechNET hands on exercise). It will be a learning experience.

Let’s consider this a Primer, a very basic instruction in the relationship between RGB and CMYK color. You can thank the folks who brought us the Canon TechNET conferences. I do wish they would bring them back. I think that the newer SEs could benefit greatly!

That’s My $0.02
Vince McHugh


What color is your blue?

August 25, 2009

Have you ever heard a customer tell you that the color on their new MFD is “wrong”? I always think, but never say “based on what?” Color is relative, what most people mean when they say the color of their new printing device is wrong is that it is different than the way their old printer or MFD use to print. Or maybe it is different than the way they would like it to print. Even if it is demonstrably better, it’s different, and different makes it “wrong” to the customer. At least that will be their initial response.

Many years ago I was called in on a new installation of a high end color copier\printer. It was a Graphics House with a Father \ Daughter team of Graphic Artists (GA). They told me that they did not like the out of the box color that they were seeing and I told them not to worry we can adjust the color. After discussing what they wanted to see, I did a calibration and then made a few initial changes in the settings of the Fiery Rip. But when I printed out one of their files and showed it to both of them they gave me the following response at the exact same time.

Father: “That sucks!” -vs Daughter: “That’s perfect!”

Welcome to my world, as I said, color is subjective. I responded to the both of them, when the two of you figure out which one of you is “right”, let me know and I’ll fix it. Who do you think won that argument? Right, The daughter did. It was perfect, because she said it was. It was what she wanted, or what she expected. That made it “right”, at least in her eyes.

I have also had a customer show me a Pantone color, a JPEG Image, and a CMYK color, and say “this”is our company Blue. Which one? Because each of these is a different color (space). And they will often print differently. There are of course great color management tools, especially on the Fiery rips. But even Canon & Konica Minolta (as well as some other Manufacturers) are getting better at being able to give us better color control. The OEM controllers have come a long way, but for critical color I will still recommend as Fiery Rip.

But it is just as important to educated our customers about color. One of the things I am seeing is more WYSIWYG (What you see is what you get) color than ever before. I show up and have an irater customer telling me the color is “WRONG” on their brand new MFD. Then I look at it and compare it to what I see on the screen and it is WYSIWYG. The customer may even acknowledge that it looks just like the image on the monitor but they still insist that it is “WRONG!!!!”. But what they mean is it’s different. They took great pains, and a lot of trial and error to get the image that they don’t like on the screen to look right on their old printer. So when the new MFD prints out just like it looks on the screen they’re upset because they don’t want to have to rework all of their old documents to make them look they way they use to on their old printer. You can liken it to a person who learned to ride a bicycle with crooked handle bars. When you give them a bike with straight handle bars they have a tough time riding it because even though they know its the way its suppose to be, it feels wrong to them.

Color is also an emotional issue to most people, so you can’t expect people to be completely rational about it. Even if they know that the color is better they may not want to acknowledge it because that would mean more work for them to correct their old files. So they will say it’s wrong, to make it your problem, and not their problem. And since they probably have not yet signed the D&A, guess what, it IS your problem. I hope you have a talented SE or Color Specialist (we have several).

The good news is we can often set up profiles or even custom color curves that the customer can call up ‘on the fly” to print their old files so they will look pretty much the way they use to, but allow them to take advantage of WYSIWYG color going forward. While it may take some time getting use to riding the bike with straight handle bars, it’s worth the effort. And if the customer is willing to work with their SE or Color specialist it will make the transition easier, and very much worth the trouble.

That’s my $0.02
Vince McHugh