CMYK: Eliminating Dull Colors In Gradients

Before I begin, I have to make a point that is probably obvious for a lot of you, but necessary. This entire post deals with getting the most out of CMYK mode. However, since monitors work with RGB, I can only ever show you (and you can only ever SEE [until you actually print it]) the RGB representation of the CMYK colors. For many of CMYK's colors, the RGB representation will be pretty accurate. However, as I touched on in my previous post and will go further into in future posts, it is the richest and strongest of the CMYK colors that you cannot see with RGB. So if I'm making the point that a strong cyan in CMYK mode looks great and you're thinking it looks just the same as the one made in RGB mode, that's because you can't see how good it looks until you print it.

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!

Photoshop's CMYK Proof: Why To Avoid At All Costs

When I was tossed into a graphics design job, I had very little understanding of CMYK. I understood RGB just fine, but upon learning that my projects aimed for print ads and the like had to be in CMYK, I went the ultimate newbie route: designing my ads in RGB and converting them to CMYK when I was finished, praying they would look okay. Sometimes they looked okay, sometimes they didn't. It was a complete crapshoot. I didn't want to simply design in CMYK because I got really washed-out gradients and I liked some of the filters that could only be used in RGB mode (something I use rarely if ever now, but when I was first starting out filters just seemed too cool to give up).

After getting frustrated with the drastic changes some of my designs took when converting them to CMYK, I did some googling to find out that you could design everything in RGB mode with a "CMYK Proof" on that would show what the RGB design would look like once converted to CMYK. I found multiple people not only listing it as an option, but actually suggesting that people use it for their designs. And it really did seem like it was the best of both worlds: access to all the RGB features while knowing what the final product would look like. Even for people who have little use for RGB filters, there didn't seem to be any downside to using the CMYK proof setting. I used this for ages with the only noticeable issue being that occasionally a final conversion does NOT look the same as the proof did. It only seemed to happen when I was using multiple style layers and layer blend options, I'm guessing it just came down to software errors, but simply flattening the image in RGB mode and then converting worked for me, so I thought everything was perfect.

Where I noticed an issue with the CMYK proof was when I was doing some test prints of a document I was making in InDesign. The document was a small little brochure of the products that the company I worked for was selling. Let's call the company MKD. The official logo for the company was an Illustrator vector CMYK file. The logo was simply the name of the company with CMYK values C = 100, M = 0, Y = 0, K = 0. In other words, completely cyan. For the brochure, I needed to make a little edit of the logo for one of the pages. It was going to be a one-time use, so I lazily made it in Photoshop instead of making a new vector in Illustrator. Like I normally do, I went ahead and used RGB mode with a CMYK proof. I dragged the original logo into Photoshop and hacked away at it, converted it into CMYK mode and then put it in my InDesign document. Everything looked good. When I printed the document to see how it would look, the original MKD logo looked amazingly bold - a nice, deep cyan. On the other hand, the edited one I made looked bad. The cyan was completely washed out and did not stand out at all.

I was confused, to say the least. Both images looked identical in color on my screen. The color I was seeing was this:

in both CMYK and RGB (when viewing them on my monitor). Look like a nice cyan, right? But for some reason it only looked good when the one made originally in CMYK was printed. To understand why, you have to understand a bit about how CMYK and RGB are different. If you've worked with CMYK before, you've probably noticed the fact that it's hard to get some of the boldest colors out of it. For example, if you're trying to use an RGB value of R = 0, G = 0, B = 255 (all blue), you'll get something like this in RGB:

On the other hand, if you convert that value to CMYK (or if you try to use RGB 0,0,255 in CMYK) you will get a color like this::

So, why the difference? CMYK uses subtractive color, while RGB uses additive color. When the red green and blue colors for each pixel on your computer monitor are off, the monitor is black - no color (roughly). Every time a color turns on, color is added. When color is added, the screen gets brighter and brighter and when all colors are on, the screen is white. It's not always easy to tell, but this animated GIF might help to show this. The gif goes from black to blue to cyan to white, RGB values 0, 0, 0 to 0, 0, 255 to 0, 255, 255, to 255, 255, 255. It becomes slightly brighter in each frame.

CMYK, on the other hand, is the opposite. It makes sense when you think about it. Monitors are black (no color) until colors are added, while paper is white (all color) until colors are removed. When my original CMYK logo was printed at 100, 0, 0, 0, it was printing cyan ink at its fullest. Since this is subtractive color, that means that to print cyan like that, the ink is removing all colors BUT cyan. Using the colors given in the CMYK format, to make a blue color, you must add magenta to cyan. So a decent representation of blue in CMYK is 100, 100, 0, 0. To make the best blue color in CMYK you might use less magenta than that, but 100, 100, 0, 0, should be pretty close, and it works for the purpose of this explanation. So consider the nicely printed cyan at 100, 0, 0, 0. This subtracted all colors BUT cyan from the paper it was printed on. Now, if you have to add more color (magenta) to get blue, you are adding MORE subtractive color, which is taking away from the color and boldness of the print-out. So when you are subtracting both cyan AND magenta, you're taking away a lot of color to get the best blue. The result is a color that looks blue, but loses a lot of the boldness and saturated look of the color. That is why the "CMYK" image above looks so much less bold than the "RGB" image, even though they are both trying to represent blue. When you add 100% yellow to that washed out blue, you ideally should get black. Because of the shortcomings of the subtractive use of ink, it ends up being more of a dull gray. Here is the RGB representation of CMYK 100, 100, 100, 0:

That's why the K (black) layer of CMYK exists, to add a rich darkness that cannot be achieved with just CMY (it also helps that black ink is typically quite a bit cheaper). If you add 100% black to that color to get CMYK = 100, 100, 100, 100, you will get the richest print black, and the RGB representation of 0, 0, 0 (no color).

Okay so now it's time to actually get down to why my printed logo looked bad when it was made in RGB, and why working in RGB for work that will eventually be CMYK is typically a bad idea. It's clear that using only CMYK colors to represent RGB colors would not look good (as shown by the lackluster CMYK blue that can be represented much better in RGB color). This is because CMYK has a different color gamut (range of colors) than RGB. It may initially seem like CMYK has a smaller color gamut than RGB, and one that can fit entirely inside of RGB's color gamut:

The reason it seems this way is that any of the CMYK colors you're seeing on your monitor are being represented by RGB values, so RGB seems to be able to show all CMYK colors, and it CAN show all the CMYK colors that you are familiar with seeing on your monitor. But that's exactly the issue. The colors that are unique to CMYK can never be represented accurately with a monitor. And unfortunately, the colors that cannot be represented by RGB are some of the best CMYK colors. So working in RGB for CMYK projects makes it so that you cannot use the strongest CMYK colors, the ones that stand out the most and look the boldest. A better representation of the color gamuts of CMYK vs RGB is something like this:

Keep in mind this isn't meant to be a quantitative graph, it's only meant to show that there ARE CMYK colors that cannot be represented by RGB. Among these colors would be CMYK: 100, 0, 0, 0; CMYK: 0, 100, 0, 0; CMYK: 0, 0, 100, 0; the three boldest colors CMYK can show. A simple way to test this is to create an RGB Photoshop document and a CMYK Photoshop document. Open the color picker, and enter in manually CMYK values of 100, 0, 0, 0. Then use the paint bucket tool to fill the image with that color for both documents. You will notice that the RGB representation (what you're seeing on your monitor) of both the RGB  and CMYK documents' 100% cyan color appears to be the same. Now, use the eye-dropper tool on that cyan color to see what its values are in both documents. In the RGB document, you will see RGB values of 0, 174, 240. In the CMYK document, you will see RGB values of 174, 239, 0. As you can see, the RGB representation in both documents is almost exactly the same, which is why they look the same on your monitor (side note: I'm not actually sure why they are ever-so-slightly different, I would have expected them to be exactly the same). If you do the same thing with the eye-dropper, but this time look at the CMYK values, you will notice a different story. The CMYK document has values of 100, 0, 0, 0 that we originally used: completely cyan. RGB on the other hand, has values of 69, 14, 0, 0. Now, as was discussed earlier, adding 14% magenta will subtract color from the printed document, making the cyan stand out less. But more importantly, the actual cyan color itself has dropped from 100% to 69%. That makes a HUGE difference on printed documents, and it (combined with the added magenta) explains why my MKD logo made in RGB looked so much worse than my logo made in CMYK.

You see, when working in RGB, the file stores the RGB values ONLY. It doesn't matter what you entered as a CMYK value or which added images are CMYK. The RGB pixel data is all that will be saved in an RGB document. The CMYK value that you get using the eye-dropper tool (or from converting from RGB->CMYK) is just a rough conversion from RGB to CMYK. What that means is that putting the rich cyan CMYK color of 100, 0, 0, 0 into an RGB document will only store the RGB representation of the color, which is something close to 0, 174, 240. This is NOT the same color, since the 100, 0, 0, 0 CMYK color is outside of RGB's color gamut. So you are losing the rich cyan color that only CMYK is able to represent when you put it into an RGB document. Then, when you convert it back to CMYK (or just print it in RGB), the color that is printed is the CMYK color that your RGB color maps to. Since RGB cannot map to the bolder CMYK colors, it maps to  the closest color it is able to: the ugly 69, 14, 0, 0. And THAT is the reason that working in RGB for CMYK documents is a terrible idea.

And that's the simple distinction, in CMYK your color is going to look beautiful, in RGB it will not. I know that might seem like a small difference for just one logo designed poorly, but the issues with that one logo apply to all CMYK image design. You could have entire images that get their colors cut down because you were working in RGB. It doesn't happen all the time because you have to use some of the rich cyans, magentas, and yellows to experience that issue. But here's the thing: knowing that those colors are the richest colors you can get out of CMYK, you SHOULD use them in your documents. You can create the absolute best CMYK images by using everything that an RGB image would NOT allow you to use. If you're like me, you probably hate how washed out colors are in CMYK compared to RGB. Well, if you use CMYK properly, you can create images that are just as bold as your RGB ones. The trick is simply knowing how to do so. I hope to touch on this in my next post, which will hopefully be up within the next few days. EDIT: Here is the first part of said post.

So my explanation for the RGB/CMYK issue is complete. If you're exhausted after reading all of that, I understand. I know it was a lengthy explanation. It might seem unnecessarily lengthy too, but I think hitting all the details is important. The main reason I made so many of the mistakes I did early on in my graphics design career is because people DID NOT go into lengthy detail. I simply heard a few people online say "hey, use CMYK proof" and I thought it was great. If I had known all the details I know now, I would've avoided it like the plague. My hope is that in going into detail like I do, you will be able to make your own decisions about how you want to approach your image design, and hopefully can come to your own conclusions about how you want to design, without just trusting uninformed advice from strangers. That being said, I have to admit that I usually do really enjoy discussing the nitty-gritty details of image design, processing, etc., and I want to thank anyone who took the time to read the full post. I put a decent amount of work into it, and it took me awhile to write, so if you gained some knowledge (or even if you hated it), I'd love to hear from you.. If you have any other comments, concerns, complaints, or questions, I'd love to hear them as well. Thanks!