Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member
Hey gang, this is Deke McClelland. Welcome to Deke's Techniques. This week, I'll show you an alternate method for converting an RGB image to CMYK, that retains the original luminance data. Because what we're doing is we're turning the red channel into the Cyan channel. And the green channel into the Magenta channel, and the blue channel into the Yellow channel, via a special mode known as Multichannel. Now, just so we're on the same page, I want to make sure that you understand that you only convert to CMYK when you're commercially reproducing an image.
That is, you're sending it out to a commercial print house. If you're printing it locally, to your ink jet or laser printer in your home or office, then you leave it in RGB, because those print drivers expect RGB images. If you convert to CMYK you'll just mess things up. So, with that in mind, assuming that we're all commercially reproducing our images. Here's an alternate method, for converting an RGB image to CMYK that retains the original luminance data. We're going to start things off inside this vividly colored RGB image. And I'll show you what happens when you perform a standard CMYK conversion. Converting the CMYK is the single most destructive modification you can make to an image inside Photoshop.
And that's because the color spaces are just entirely different. So rather than convert your original image, in which case you run the risk of saving over it which would be a crying shame. You want to go on to the Image menu and choose the Duplicate command, and then let's just go ahead and call this guy Standard CMYK, because that's where it will be. And I'll click OK, in order to create this duplicate file. Then we want to go up to the Edit menu and choose the Color Settings command which also has a keyboard shortcut of Ctrl+Shift+K or Cmd+Shift+K on the Mac. And inside this dialog box here, assuming that you're working in the States, change the settings from North America General Purpose 2, to North America Prepress 2. If you're working in another country with a localized version of Photoshop, then select something equivalent.
But what we need is for the RGB space to be Adobe RGB 1998 and for CMYK to be some default. In the states, it's U.S Web Coated SWOP v2, which is just fine. Then turn off these pesky checkboxes down here, they'll cause you no end of grief if you leave them on. All three of them need to be off, and then click OK. Now you want to go on to the Image menu, choose Mode and choose CMYK Color. And if you're working along with me, you'll get two warnings. First of all Photoshop will ask you if you want to Flatten the Image, that is get rid of the independent layers.
Which you have to do if your image contains Adjustment Layers, because otherwise it won't function properly. So if you have Adjustment Layers, before you choose the CMYK command you want to go ahead and merge them into the Pixel Base Layers. In my case, I don't have any specialty layers that are going to cause me problems so I'll go ahead and click on the Don't Flatten button. Next Photoshop will tell you that there's another way to work. If you want to convert to a specific CMYK space, then you want Choose the Convert to Profile command from the Edit menu. In our case, that's not an issue so just go ahead and Click OK. And did you see what just happened? I'll go ahead and press Ctrl+Z or Cmd+Z on a Mac.
Keep an eye on the contents of the image window, this is the original RGB image, bright, vibrant, stunning. I'll go ahead and press Ctrl Z or Cmd Z, again, to switch back to the CMYK version of the image, which is much dimmer and sort of murkier. And definitely not as vivid throughout. And, most troubling, these color swatches are totally messed up. I'll show you what I mean. I'll go ahead and switch back to the bright vibrant RGB image. And I'll select the Eyedropper Tool, which you can get by pressing the eye key and then bring up your Color panel.
And make sure that your RGB sliders are visible. And now let's go ahead and click in these bottom swatches, because they're the most indicative. If I click on the last one here, the Magenta swatch, notice that this is true RGB Magenta. That is the red and the blue values are maxed out to 255. The green value set to just 0, so there's no green in there whatsoever, because after all green and Magenta are complimentary colors. So you don't want any green in your Magenta. Now go ahead and click on this violet one right there and you can see that we've got half red, so 128 r, no green whatsoever and blue is maxed out to 255.
And that's about the brightest violet you're going to get. Now click on the blue splotch and you can see that's pure blue. No red, no green, just 255 blue, that's it. And then, finally I'll click on Cyan and you'll note that we've got R0 and green and blue both maxed out to 255. Compare that to what happened to the CMYK conversion. I'll go ahead and click on it. We need to switch from the RGB sliders to the CMYK sliders. And now I'll click inside the Magenta swatch. The Magenta value should be cranked up to 100%. Because that CMYK Magenta for you. But instead, we've only got 80% Magenta, and we've got 11% Cyan. If I click inside the violet swatch, we've just got a mess. We should have a much higher Magenta value.
Now click inside blue and that should be 100% Cyan plus 100% Magenta, it's not so we have a low saturation blue instead. And then finally Cyan that should just be Cyan ink, right? But if I click inside it, you can see that that's not what we have. We have 87% Cyan so pretty high, but then we've got 20% Yellow, where'd that come from? What we want, I'll go ahead and switch to the final version of the file that we'll be creating, is these colors right here, which are as saturated as they get. If I click in Magenta, sure enough its a 100% Magenta nothing else in there.
If I click on the purple swatch its a 100% Magenta plus 50% Cyan precise values that work here. If I'll click inside blue sure enough I've got a 100% Cyan plus a 100&% Magenta without anything else and if I click inside Cyan just a 100% ink. No other impurities whatsoever, with magenty Yellow and Black values are concerned. The thing to bear in mind is, that we will see different colors. So this is the original RGB image and this is the final version of the image that will we creating, using the Multichannel approach.
So you are getting a different effect, but that's inevitable in the world of CMYK. In any case how we go about getting this? Well, you want to switch back to your RGB colors image, you need to have a CMYK version of the image handy by the way, so to make sure you've got it. Then switch back to the RGB image, go back to the Image menu and chose Duplicate once again. And I'll call this guy, Multichannel Approach, let's say, and then, I'll click Okay. Go ahead and Zoom In. I'll go about to the image menu choose mode and choose Multichannel. Now Multichannels (UNKNOWN) mode, they just basically breaks the channels up from each other.
Now let me Escape out for a moment and switch from the Layers panel to the Channels panel. So you can see, that we've got this RGB image and then we've got the red, green and blue channels. And then we've got an extra alpha channel as well. Well, we don't need the Alpha channel, so you can go ahead and grab that guy and throw it away. In fact, you need to do so. Then, return to the Image menu, choose Mode and choose Multichannel. And what this is going to do is just split up the channels into a document that does not have a composite image. So, we won't see an RGB image any more. We'll just see independent channels and they'll get new names.
Also notice this alert message, Flatten layers. There is no don't flatten, it's just OK or Cancel. So if you want to move forward you have to flatten your image. Click OK to do so and you'll end up with this thing that doesn't look the least bit right. And not only that, we've got a Cyan channel, we've got a Magenta channel and a Yellow. But they're the exact same channels we had a moment ago. So the red channel just became its complement Cyan, and the green channel became it's compliment Magenta. And, the blue channel became its complement, Yellow. Next, what you want to do, is add a new channel by clicking on this little page icon at the bottom of the Channels panel.
That will create a new alpha channel filled with Black. It needs, however, to be filed with white, so just go ahead and press the D key to establish the default colors. White is now the foreground color, because we're working inside an alpha channel. So press Alt+Backspace or Option+Delete on a Mac in order to fill that channel with white. Now the reason we just created this channel is because it's going to serve as our Black channel. So we've got Cyan, Magenta, Yellow, and this channel Alpha 1 that will become Black. As soon as you go up to the image menu, choose Mode and choose CMYK Color.
And you're going to get that alert message about how you can specify space using the Convert to Profile command. Just go ahead and click OK, and you'll end up with this effect right there. Now, might not be everything you hoped it would be. However, let's start with the good news. Even though it looks pretty washed out, we've got great color swatches. Check it out. If I click in the Magenta swatch, it's 100% Magenta, and the CYK values are all zero. And if I click inside Cyan the other values are zero, so no color impurities whatsoever.
I'm not going to go through the other swatches, but believe me it's the same story. If I click inside Yellow, 100% Yellow. If I click inside Red, we've got 100% Magenta plus 100% Yellow. Everything's exactly the way it ought to be. The problem is the image is washed out, we want it to look like this. And so, here's what you do. I'll go ahead and switch back to the standard CMYK conversion, because now we need it in order to retrieve the contents of that Black channel. So go ahead and click on the Black channel here inside the Channels panel, and then press Ctrl+A in order to select the entire image.
And I'll zoom out a little bit so you can go ahead and see the marquee around the entire image here. And then go up to Edit menu and choose Copy Merged, or you can press Ctrl+Shift+C, Cmd+Shift+C on the Mac, in order to copy the contents of that channel across all of the layers. Now switch to your Multichannel image in progress. Click on its Black channel, and just press Ctrl+V, or Cmd+V on the Mac, which is the standard keyboard shortcut for the pace command. And then return to the CMYK composite, and you can see that's made a big difference.
So this is without that Black channel. This is the image with that channel. Notice it doesn't harm any of the color swatches at all. You may want to increase the saturation of color all the way around, because the original RGB image is highly saturated. And to do that, go to the Layers panel and drop down to the little black white circle icon at the bottom of the panel, click on it. And notice that the vibrance command is dimmed, it doesn't work in CMYK. So instead we'll use the standard Hue Saturation command.
This is going to sound a radical to but you can total get a way with it. Go ahead and take that saturation value and crank it all way to a 100%. Now it may look like we've got a few problems here, a few harsh transitions, and to get rid of those. Just go ahead and return to the Layers panel, and change the Blend mode from Normal to Color. And notice now that those colors will drop back into place, and now you can make a decision about whether you want to reduce the saturation value. In which case you double click on the layer thumbnail here, and take that value down to 80% for example. And then, hide the Properties panel, and we end up with this effect here. Now, granted, it is not, in any way, shape, or form identical to the original RGB image.
We're just not going to get these colors in a CMYK space. But it is a very interesting effect, as you can see here. That we're able to achieve by converting the image from RGB to CMYK via the Multichannel mode. Alright, so what I just got done showing you is very interesting, but it's also exceedingly dangerous. And that's because we've got way too much ink in the shadows. We've got tons of Cyan, Magenta, Yellow and Black mixing together.
We're violating the printer's total ink limit, which means those shadows are going to smear on the page. Which is why, if you're a member of the lynda.com Online Training Library, I have a follow up movie in which I show you how to take those shadows and tone them down to make them printer safe. If you're waiting for next week's free movie, I'll show you how to take these jumping silhouettes a nd add these bright golden motion trails, or whatever they are. Deke's Techniques, each and every week. Keep watching.
Get unlimited access to all courses for just $25/month.Become a member
119 Video lessons · 49685 Viewers
117 Video lessons · 36963 Viewers
113 Video lessons · 81091 Viewers
65 Video lessons · 10277 Viewers
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.
Your file was successfully uploaded.