If you haven't, I suggest you read my previous post here before reading this one.
I'm guessing I don't need to explain my motivation for this post to anyone who has used CMYK before. Dull colors seem to be a necessary evil of CMYK. The bad news is that in some cases it's true that you simply can't get colors to be as rich as you'd like using CMYK. It's most noticeable when you're using bold blues and indigos. The good news is that even if you're completely set on using blue in your design, if you're willing to use more of a cyan color, you can not only use the best cyan RGB has to offer, you can actually get something even better. Before I go fully into the boldness issue for individual colors, I'm going to talk about an arguably more frustrating issue of CMYK, and one that's easier to illustrate: gradients.
Making a simple gradient from black to full color is something we've all done. There are plenty of reasons why you would. Creating cool radial effects, or even as the very base step for countless great designs, you use them everywhere, and it's extremely simple. Open the color picker, select one color as black and the other as a strong color in the top right corner somewhere. For this example, let's use a sort of cyan/blue mix. Here's what we get trying to make this simple gradient in CMYK:
See how the blues in the bottom half especially don't just look like a dark blue. They're more of a grayish blue that makes the gradient look really ugly, especially in more complex uses. Note that color gradients don't have to be something you make with the gradient tool. Any transition from one color to another is a gradient. This includes, for example, Render Clouds:
While less obviously gray-looking, the middle colors of the gradients are pretty dull. Especially when you compare it to this cloud rendering made in RGB:
The middle colors here are strong, dark blues instead of a murky mix of colors, and as a result the whole image looks stronger and clearer. The difference isn't coming entirely from CMYK's blue compared to RGB's blue (though part of it is). It's from a combination of factors, from the way gradients are blended in Photoshop, to the way CMYK works (the fact that CMY on its own doesn't produce a proper black, and K needs to be added has a lot to do with the issue), to the way the Photoshop color picker works (it's definitely designed with RGB in mind, not CMYK).
Now take a look at this cloud rendering made in CMYK with just a slight tweak in color selection:
Some of the boldness of the darker blues isn't QUITE as good as RGB's, but it's close and a DRASTIC improvement over the original CMYK cloud rendering, which is what most people will use initially. Here's the simple gradient using the same settings:
With gradients this bold, you can easily make really cool, bold looks with very simple manipulations:
I also feel like these rich gradients give an implied feel of some of the indigo blues that CMYK cannot reproduce as well as RGB. So the obvious question is, how do you make them? Well, when you select a black from the very bottom of the color picker, you get RGB values of 0, 0, 0, which is what we'd expect. However, look at your CMYK values. 75, 68, 67, 90. Hmm? Sure it ends up giving us a black color, even when printed. But the CMYK values seem almost completely random. That's what I meant when I said the color picker was designed with RGB in mind. You're getting a CMYK estimation of RGB's black, instead of a good CMYK black. With RGB, black is just the obvious lack of all colors, 0, 0, 0. With CMYK, because it's a mix of subtractive colors and black ink, there's really no "right" CMYK black. I've heard people say 30, 30, 30, 100 will work, but 60, 60, 60, 100 will give you the truly rich black. I've heard other variants too that use less yellow, more red, etc. The point is, there's no right answer. It comes down to where it's being used, personal preference, and difference in printers. Personally, if I'm just going for a rich black, I think 60, 60, 60, 100 is the safest black. But in most cases I use something different to match the document I'm working on.
The blue color I'm using in this gradient is CMYK 100, 50, 0, 0. Using the color picker's odd black of 75, 68, 67, 90 I get the bad gradients and clouds. Using a black of 60, 30, 0, 100, I get the rich, bold gradients and clouds. I'll get to the why in a minute, but if you're thinking that 60, 30, 0, 100 isn't going to look totally black, you're absolutely right. Here is what its RGB representation looks like as a solid color:
You can probably tell it's very slightly tinted blue. If you can't, here it is on top of plain black:
Directly in the middle of the image, you should notice a color transition. It's a very small difference, so the question is, does it matter? In almost every situation, I would say no. If you're using a gradient that transitions from black into a blue, I would say there's absolutely nothing wrong with having a blue tint to your black. In some cases, it might even be preferable, to really give your entire image a blue appearance, even in the "black"s. You can look for yourself at the CMYK gradients and cloud renderings I made earlier and be the judge, and working with gradients (or anything really) in CMYK is something where you always have to judge it on a case-by-case basis. So if we're even questioning whether or not a blue-tinted black is acceptable, why not just use a solid black color like 60, 60, 60, 100? Well let me get into why 60, 30, 0, 100 works, and I think it will become clear.
Gradients, as a lot of you know and everyone probably at least has an idea of, work by just making gradual changes for EACH color value (C, M, Y, and K or R, G, and B) from one of the colors to the other. So if you are making a gradient starting from 0, 0, 100, 100 to 100, 100, 0, 0, at the halfway point you would have a CMYK value of 50, 50, 50, 50. If you were a quarter of the way down you would have values of 25, 25, 75, 75, three-quarters of the way down and it would be 75, 75, 25, 25. So the reason why gradients using the default color picker's black look so bad is because when the colors gradually change from those black colors to blue (or whichever color you're using), the colors that aren't used (yellow in this case) are so high at the beginning that when black (K) gradually changes towards 0 along with yellow (Y), somewhere in that gray-looking area, enough black (K) is missing that the color loses its black look, and the other color values start to show. However, since yellow (Y) was so high initially in the 75, 68, 67, 90 black, when the actual color values start to get exposed, yellow is still at a high enough value that you won't just see a dark blue, you will see an ugly mix of colors, something like 82, 63, 49, 66 (a sample from the gray-ish area of the bad gradient) that results in a sort of gray, dull color. On the other hand, when you're making a black to blue gradient in RGB, you start at 0, 0, 0, and you only ever add blue to get to 0, 0, 255 so you never end up with a bad mix of colors. Now if you use something like 60, 60, 60, 100, it will certainly look BETTER than the 75, 68, 67, 90 color Photoshop gives you, but the same issue applies to a lesser extent: the yellow color still bleeds in and you get a somewhat gray look in certain areas of your gradient. But if you need a neutral black you can use something like that if you're okay with some added dullness. You can also play around with removing some of the undesired colors and use something more like 60, 60, 30, 100 to see how that looks. It typically won't show much of a difference (or at least not an accurate one) in RGB, but if you have access to a good CMYK printer you can test it out and see what you like.
That is why using 60, 30, 0, 100 is so great for the overall look of the gradient, even if it compromises your black. Yellow is never in it, so you will never have a color in your gradient that's a dull mix of everything. The only colors that are in the black are the ones that are in your true color on the other side of the gradient, so you get a clean, nice transition. How did I arrive at exactly 60 and 30 for C and M? The rule of thumb I use to maintain accuracy of the black to color gradient is to take the final color you're using (100, 50, 0, 0 in this case) and take each color's ratio out of 60. So if the color is half of 100 like our magenta is, you take half of 60 and use that in your black. That way, your ratio of colors will always be maintained everywhere in the gradient, and they should only get more or less black. I think the reasoning behind that is pretty solid and it typically holds up pretty well for me, but again, you have to analyze it on a case-by-case basis. If you think it has too much cyan, use less cyan, if you think it has too much magenta, use less magenta. I kind of came up with using 60 based off my own trial and error finding these to be the most accurate, so feel free to experiment to find what you like best.
Now, the reason I emphasize that this 60 ratio rule of thumb works best for accuracy when trying for a bolder color is that you actually can get a bolder gradient if you just maintain your CMY values for your black, and just add 100 black. So for this example of 100, 50, 0, 0 as our color, you would use 100, 50, 0, 100 for your black. This is bolder, but it is less accurate. Here's how it looks:
VERY bold colors, but if you look closely at the bottom, where the gradient is first coming out of black and into a color, the magenta stands out more than the cyan, which gives it a bit of an unbalanced look. You might prefer this look for its boldness, and in some cases I do too. But when you actually turn your gradients into something like what I linked before:
This uses my 60, 30, 0, 100 value, and with some simple layer blendings it turns into a very bold and accurate blue wiithout any magenta standing out. If you use the 100, 50, 0, 100 value, the magenta starts to really show up when you blend multiple layers of it. So the point is, it just depends on your use. That's a big reason of why I write these painfully lengthy explanations instead of just saying "use a ratio of 60 in your blacks" and being done with it. I hope that if you actually understand why I'm doing what I'm doing, you can make your own decisions when you need to, and can hopefully apply what you know to future problems.
And of course, when you're making a simple gradient using those strong colors of 100, 50, 0, 100 as a black, you can use more than 2 colors and knock out some of the magenta in the area where it stands out. But if you're using something like Render Clouds (which I used for the above look), you have to rely on 2 colors, so you don't have that same level of manipulation.
So I think I've touched on pretty much all I can say for CMYK gradients. I can't emphasize enough how important I think it is for you to experiment on your own with them. Maybe the biggest point to be made is that you should choose your CMYK colors by manually entering in what you want in the CMYK fields of the color picker, and not relying on the color picker itself, which doesn't give you access to everything you need. I'll touch a bit more on this issue itself when I talk about individual color issues that you come across when making CMYK works on an RGB monitor in a future post.
I write these posts with the hopes that you will take the concepts you read about and apply them on your own to make something you really love. I don't pretend to be perfect at any of the techniques I write about, I just try to share information I was never given in hopes that they will be useful to you. If you think I'm wrong, have a different point of view on something, or if you've learned something more I didn't talk about here, I'd love to hear about it. And as always ANY comments at all are always welcome. I hope you learned something useful!
No comments:
Post a Comment