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Weblog Entry

CMYK (for Those Who Do RGB)

February 11, 2005

Whether you just quit your job to pursue your dreams, or you’ve simply had a request from a long-time client, sooner or later you’re going to have to design a set of business cards or letterheads or something else that ultimately forces a trip to the printing press.

Since web geeks think in pixels and RGB, it’s a daunting new world to head into unequipped. Over the years across quite a few print jobs by now, I’ve had to learn by trial and error. As someone used to thinking in RGB, I’ve looked high and low for a good resource to turn to for help in converting that knowledge to CMYK. This may not be that resource, but I figure I’ve amassed at least the beginnings of a how-to on the subject. Consider it non-authoritative, but hopefully useful. Most of the knowledge contained within applies to Photoshop, mainly because I’ve had the most trouble with it.

CMYK vs RGB

CMYK Colour Diagram

First, the basics. For anyone who hasn’t owned a printer in the past decade, CMYK, or Cyan Magenta Yellow Black, refers to the colour of inks used in the printing process. CMYK inks combine in proportions to form solid colours; Yellow and Magenta with a bit of Black form a dark maroon, for example. But there are some major differences between the RGB colour model your computer display uses and the CMYK process many printing presses use, and that’s where the first point of confusion often comes in.

Rule Number One, above all else in print, is that what you see on paper will not look like what you have on screen. With tweaking it may be possible to bring the two closer in line, but suffice it to say that when first printing out your work there’s a very good chance you’ll find yourself horrified at the outcome. Never trust what you see on screen.

CMYK isn’t the final word in ink choice, it just happens to be fairly common. For business cards in particular, another potential choice is spot colour. No one says you have to print full colour, and thus use four inks. Effective business cards often use two or three, and the reason is simple: it can be quite a bit cheaper. But pulling out any of the three from the CMYK combination will produce ugly results, so spot makes use of solid coloured inks that span a wide range outside of what your standard CMYK combination is capable of. And specialized spot colours like metallic and neon shades are possible as well.

Of course, you can use more than four spot colours, and potentially combine spot and CMYK in the same printing, but once you start ranging into complicated print jobs the labour involved in producing them — and thus your final cost — quickly increases.

To further complicate things, CMYK can be printed digitally or on an offset press. The latter is a traditional printing press that requires a plate to be created for each colour of ink that prints. For CMYK, that means each of the four inks must be separated into its own plate and printed individually. As you might imagine, printing this way is more expensive due to the labour involved in creating the four plates, or separations as they’re known. A digital press, on the other hand, is more or less simply a colour laser printer. It may be a touch more expensive than your garden-variety office colour laser, but the output is pretty much the same. Printing digitally is generally cheaper.

Colour Management

Alright, next up — once you’ve chosen your inks, how in the world do you work with the colours on an RGB screen? This is where I’ve been stuck for years, and I’m still not sure I have a solid handle on it, but it’s worth passing on what I know (and following the comments on this article for advice from those who know better).

Note: if you haven’t mastered the curves, levels, and channels of Photoshop, now’s the time to brush up because you’re going to need them (the linked articles are the first respective results I could find on Google; they barely scratch the surface, you’ll want to keep digging).

First of all, we’ve established that an on-screen colour will not look the same printed. Again, there are major differences between RGB and CMYK, or more specifically, light-based colour and ink-based colour, that prevent this from ever being possible.

Pantone Swatches

Colour management is a deep and complex science, and the best coping strategy I’ve found so far is to try and work around it. Pantone, which you have probably heard of, is one of a number of colour-matching systems that basically gives you a palette of numbered, pre-printed swatches to choose from that accurately represent the final colour.

The advantage is that if you use that exact Pantone number, on that exact paper, you know exactly what you’re going to get. It won’t look the same on-screen of course, and your software has to support it (in Photoshop for example, when you have the colour picker dialogue open, hit the ‘Custom’ button to get a list of different colour-matching systems and their various palettes).

The disadvantage is that you won’t likely have your own set of printed swatches. An official set is pricey — a few hundred local currency for what is essentially a chunk of ink samples. You can pick up cheaper books off the shelf of your local art book store that are more approximations than accurate matches. Ideally though, your print shop will have a set on hand. If you’re able to make a trip first to go pick your palette ahead of time, you can save a lot of effort later.

Working With Process/CMYK

Colour matching systems work best in conjunction with flat colour and pre-defined gradients, so the text and vector output from Illustrator or InDesign, for example, is a great use case. But what if you’re working with heavily photographic material and don’t have that luxury? Start throwing in overlays and other forms of colour variance, and you’re going to quickly run into problems that Pantone won’t help. Without having direct access to the final output device, you’ll want to minimize test runs at the print shop to keep costs down (and avoid going back and forth to proof them) so you need to know ahead of time what you’re up against.

If you’re printing digitally, fortunately proofing is relatively simple — you have a colour printer, right? Inkjet or otherwise, these days you don’t even need a high-quality printer. A $50 special at the local hardware store is more than enough. The trick is that you’re not looking for high-end, ultra-accurate results; you’re looking for a rough approximation to see how much the colour is going to shift on you.

What I do is build my file in RGB from start to finish, and just before I’m about to print, I save a copy of the file and convert it to CMYK, then print that. If it’s a first shot, the proof will come out shockingly ugly and muddy, which means I’m on the right track. Again, this is just a rough approximation of the final colour, but it will give you a good idea of how far off the mark you are. Alternatively, Photoshop has a ‘Proof Colors’ setting (Ctrl + Y or Cmd + Y) which can apply the current CMYK profile and soft proof what it will look like on paper, but it generally won’t shift as much as an actual print will.

Now this is where the fun starts. How do you take that horrible output and get it to match the prefect vision you have in mind (and just finished creating on-screen)? Adjustments, and lots of them. You can either go back to the RGB original and adjust elements there, knowing what you now know about the final output, or you can work directly on a CMYK copy.

Adjusting Levels in Photoshop

What do you adjust? It depends on the output. If your blues are blowing out to a bright ugly green, it might be wise to back off the yellow and boost the black. If your reds are too grey, it’s worth toning down the black and bump up the magenta. How do you adjust? Again, this is where channels come in handy. I’ve had luck going back to the RGB file and lightening everything globally to tone down the black. For major 4-colour corrections it’s often worth it to flatten and save a copy of the file, converted to CMYK (Image -> Mode -> CMYK Color), and then apply curves or levels to each of the individual ink channels. I prefer levels for most operations, but more print-aware people will probably steer you to curves. Some selective masking to adjust the more problematic areas is often required as well.

Example Test Strips

Placing some superfluous bars of colour in the margins before you print can help cut down on the colour checks. If you know ahead of time which colours will be problematic, you can provide a range of tonal variations, mixing in varying proportions of ink. After a test run, assuming you’re in the right ballpark, you simply choose a better colour from the test strip and be done with it. Doing this cuts down on the printer runs trying to nail down the precise shade.

At some point though, you’ll have to get a proof from the print shop, to see how far off you were and to have a reference for further adjustment, if necessary. Printing digitally, this isn’t much of a problem — they don’t need to do much more than drop your file into their template and send it through the printer. Expect to have to come back later to view the result though, since they won’t drop everything to get your proof done.

Printing offset on the other hand, is a bit different. Unless you have the ability to create separations yourself, which you probably shouldn’t be doing anyway, the print shop will need to spend a bit more energy outputting those and running a proof. As far as I’m aware, the machine needs to be fully inked to print them too, so at this point the proof is what you’re going to get, barring any unforeseen disasters. It’s costlier to back out and make corrections at this point, although still possible.

Now, assuming your inkjet printer proved up to the task and the trial press run isn’t too far off what you were expecting, you should be ready to give the go-ahead at this stage. If you’re still not satisfied, you’ll have a guide to compare against the proofs you created earlier. You’ll be able to pick up spots that have changed dramatically between the two proofs, and assuming you can tell why they’ve shifted (basic colour theory applies here — yellow and cyan make green, red and yellow make orange, anything and black makes dingy brown or purple) you can adjust to suit. There’s a certain amount of guesswork still, but armed with your set of proofs you have an effective tool for comparison, which you can use to squash all but the subtlest of colour shifts.

Working With Spot

Let’s say you’ve decided to use spot colour, you’ve picked your Pantones, and now you’re ready to design. What next? Now you have to start thinking in limited colours, and your software is going to play a big role; nothing you know about CMYK translates to spot. My experience is limited to Photoshop and Illustrator, but there’s a relatively easy method of pulling off spot in each.

In Illustrator, create new swatches for your custom colours by clicking on the arrow in the swatch palette and hitting ‘New Swatch’. In the options menu, choose ‘Spot’ as your colour type and adjust the sliders to approximate your colour choice. Repeat for each ink, and you now have a set of spot colours to work with. Use them as solids, adjust their opacity, or mix them together in gradients; as long as you stick to this set, your Illustrator artwork will be set up properly for the print job. Technically they don’t even have to be the same colour as your final output either. Because each separation is printed as a greyscale version of the colour channel, it’s unaware of any actual hue; the Pantone you choose is what actually gets printed, not the on-screen preview.

Working with spot in Photoshop is a bit less straightforward. Essentially, you need to think of each ink channel as its own independent mask, and consider the limitations that come with that. Layers are out, for example, which also makes text uneditable; building a file this way is tedious at best.

Example spot channels in palette.

First, to understand how Photoshop works with spot. Open a photograph and convert it to CMYK (Image -> Mode -> CMYK Color), then go into the channels palette and drag one of the channels to the trash can at the bottom of the palette. Instant spot! You can view each individual channel in greyscale by making sure it’s the only one with the little visible eye icon next to it, or view them all as a blended preview of what they look like combined by enabling all eye icons.

Given your subject matter though, it’s probably none too attractive at this point. You’ll want to adjust the ink colours, which you can do by double-clicking on any channel (the ‘Solidity’ option is for your monitor only, it won’t affect the printed output). If you create a new channel while working in spot mode, it defaults to an Alpha channel, which you can then change to a spot channel by again double clicking, and selecting the appropriate radio button. Or just hit the arrow at the top of the Channels palette and create a ‘New Spot Channel’.

Working in spot mode.

Now what you’ll want to do is devise a strategy to build up each of your ink channels. Rather than working on a composite whole and selecting colours for each new item, you mix your colours by adjusting the ink proportions in various channels. Darker means more ink, lighter means less.

It’s a completely different way of interacting with Photoshop. Aside from layers, many of the usual tools are available to you when working in spot mode, and if you’ve spent time developing advanced masking skills you can adapt that knowledge and feel right at home. Otherwise, the least elegant way to work — but perhaps easiest to manipulate — is to build a set of greyscale files, one for each ink channel. Layers and editable text are usuable, but any areas that require more than one colour would need to be duplicated across both files, which makes editing tedious. You lose the ability to preview the combined channels though; the only way to get that back is to save a flattened copy of each greyscale file, then combine each in a new spot file, one channel at a time. Tedious!

Proofing spot colour is actually fairly simple; you know which Pantone colours you’ve chosen, so you can roughly match those in Illustrator’s colour picker. Make sure to print a test strip of your swatch to make sure you’re getting an accurate picture of the shift between the solid colours on screen and those on paper. Proofing in Photoshop is usually slightly more difficult due to the relative complexity of the subject matter compared to what you might be proofing in Illustrator, but the same process applies — make sure to print test swatches, keep your Pantones firmly in mind, and all but the most subtle of blends should be predictable.

Monitor Profiles

Finally, I’d be remiss to point out that there are advanced colour matching systems (both hardware and software) which have been developed specifically for the purpose of colour matching between screen and printer. Should you care? Probably not — they may save time for those spending a large part of their day thinking in CMYK, but for simple jobs where the basic concept of working with CMYK causes enough doubt to spur this article, it’s likely they’re overkill.

One thing that might be relevant though is the Monitor Profile your software uses. For general RGB work it’s best to turn off colour management; for printed work, the software needs to somehow interpret CMYK on-screen. There are colour profiles for different types of paper which depend on your geographical region; North America uses SWOP, for example.

Aside from accuracy in CMYK mode, the most useful function of having an accurate CMYK profile is the out-of-gamut warning you can pull up in Photoshop when working in RGB mode. By hitting Ctrl + Shift + Y or Cmd + Shift + Y to toggle on and off the warning, you get a layer of grey indicating spots in the file that are out of the CMYK colour range and most likely to shift dramatically. Simply by knowing these areas in advance, you have a map of which areas in your image need the most coddling, and much of your colour management issues obviate.


Robert says:
February 11, 01h

This is a great primer for understanding process and working with four-color and spot, but I have to comment on a couple of things you’ve pointed out.

If you want the best results, ALWAYS start out working in CMYK. That just puts you one step closer and saves a whole lot of extra work. And if you’re planning to work in spot color, it’s always your best bet to pick up a color reference book. Yeah, they can get pricey, but they can be purchased individually like the Spot-to-Process book you’ve shown here. And besides, what are we, working for free? Just part of doing business, I say.

Also, I thought it was worth mentioning that in Illustrator, you can simply open up any of the preset swatch palettes and choose your spot colors (PMS, Trumatch, Toyo, etc.) from there. No color sliders required.

It’s funny how this seems so basic, myself having worked in print for so many years. I’ll tell you now, it’s a good thing you’ve written this up, because it’s quite an issue when I have to deal with files supplied by primarily “screen” designers that don’t have the slightest consideration for print in their work.

Still, this definitely puts some perspective on what adjustments one must make when switching mediums. Being a print designer who started web design several years ago, I can remember instances where I’ve had to explain the exact opposite to other print designers.

February 11, 01h

although i only do the occasional spot of print, this is truly enlightening. great stuff.

anders says:
February 11, 01h

I found Jim Ames’ book “Color Theory Made Easy: A New Approach to Color Theory and How to Apply It to Mixing Paints” to be a pretty good introduction to the basic theories. It’s focused on mixing paint, but can be applied to computer stuff pretty easily as well. It’s particularly interesting because he starts with the assertion that CMYK is the most natural color system and proceeds to build the rest of color theory on top of that. RGB only gets a few brief mentions.

Mike D. says:
February 11, 01h

Very good overview Dave. A few more things to add:

1. With regards to working in RGB or CMYK from the start, most print designers work in CMYK from start to finish and although I do equal parts print and web, I choose CMYK as well. All of the conversion issues which occur at the end of the process are moot using this method. Just about the only thing you can’t do in CMYK that you can do in RGB is some of the crazier KPT filters and whatnot (some are RGB only). I guess it also depends how you internally mix color in your head. When I need orange, my internal mixer says “Just mix some magenta and yellow ink” as opposed to “add some red light, some green light, and no blue light”.

2. If you are going to work in RGB and convert at the end (which is perfectly fine), make sure you’re also vigilant about ink coverage issues. If, for instance, you were to bump each CMYK channel up to 100%, you’d have 400% ink coverage which would completely oversaturate your pages with ink and likely ruin some of them. Different paper has different ink limits, but it’s an important thing to keep in mind. Your initial conversion to CMYK won’t have any saturation problems but any adjustments you make directly to the channels can. Just keep an eye on the totals.

3. Know your blacks. To make a nice rich black in CMYK, use 60C 40Y 40M and 100K… not “just black”. Black ink is extremely transparent on paper and without fortifying it with other colors, it won’t be true black.

4. When using spot colors, know when to knockout and when to overprint. Knocking out is the default mode whereby two spot colors are never printed on top of each other. Sometimes you will want to overprint though in order to create a “third color” or avoid trapping issues.

5. With regards to proofing, yes, the very expensive final proofing method you mentioned is called a “match print” and it requires full separation. Ideally, this should only be done once… right before it goes to press. Before you get to that step, however, you can have your printer output an Iris proof (better) or a Rainbow proof (cheaper), both of which are reasonably priced and calibrated to match the press as much as possible. I try to output an Iris or Rainbow for every 4-color job I ever do. Saves you money in the end, and not as embarrassing when you have to tell the printer you’re running back home to fix that greenish skintone you missed on screen.

Dave S. says:
February 11, 01h

“If you want the best results, ALWAYS start out working in CMYK. That just puts you one step closer and saves a whole lot of extra work.”

I’ve heard it both ways from those in the know. From what I understand, the problem with working directly in CMYK from the start is that you have a layer of interpretation between you and the actual colour values, in the form of your software’s colour profile. If you don’t have that set up properly (and let’s admit that most web people won’t have the first clue how to do it, myself included) you’re still going to be relying on the printer.

There are no doubt advantages in mixing colour with the CMYK sliders though. If nothing else, you get a feel for how the ink interacts, and how little black you usually need.

Also, I’m not sure if the latest versions are better for it, it’s been a while since I’ve checked, but Photoshop used to disable some functionality when in CMYK mode.

Dave S. says:
February 11, 01h

Also, correct me if I’m wrong — but if you decide to work in CMYK from the start you’ll probably end up pulling in RGB photos or other source material that has to be converted, and get stuck dealing with all this nasty colour shifting stuff anyway, right?

7
Patrick says:
February 11, 01h

You have unbelieveably good timing. Just yesterday I was pestering a designer friend of mine for a rundown on how to go from Web color-thinking to print. It’s confusing and fascinating. After designing for the screen for so long, I admit it gives me a little shiver of delight when I see something come out crisp and clean on paper.

February 11, 02h

Thanks for the tips, Dave.

I’ve always just burned through lots of test prints with these things. The only piece of advice you give that I figured out on my own way the ‘inexpensive inkjet’ bit.

With some 11x17 posters a while back, I just printed several thumbnails and detail crops of them to get a sense of the color shift.

Mike D. says:
February 11, 02h

You pretty much have a layer of interpretation going on regardless. RGB used to just be RGB, but now there at least five major RGB colorspaces including Apple RGB, Adobe RGB, sRGB, and others. In fact, sRGB (which is what most web people are used to working in) is *extremely* limited in its color choices. The amount of colors available to you in sRGB mode are much much less than with, say, Adobe RGB, and some of the more professional colorspaces. In other words, even if you’re going to use RGB, use a professional RGB space.

As for converting photos, yes, that’s an issue, and a lot of it depends on the original source colorspace. All drum scanners and high-end stock photo houses will give you your photos in CMYK from the start, but to your point, a lot of the photos we use these days come directly off our digital cameras (which tend to output to RGB). Still though, I’d rather get the conversion done right away and apply adjustments in the native printing mode in most cases.

Josh Mast says:
February 11, 03h

Excellent article. This subject has been bugging me for a while as I’ve been wanting to expand into print but have been totally overwhelmed by all the CRAZY NEW STUFF.

February 11, 04h

As others have mentioned, I really think it is better to work in the color space of your intended output. First, color shifts DO happen when converting from one color space to another. Thus, if you are outputting in CMYK, you should at least do your final color correction in CMYK. If you are using photoshop filters that need RGB, apply all of those filters, save a flattened copy, and then go into CMYK for final color correction. Remember, each time you convert to a color space, image data is thrown out so you want to minimize this as much as possible.

If you receive RGB images that only need basic levels and curves adjustments, it is much better to do those in CMYK if color accuracy is important. Working in CMYK also gives you access to a black channel, a distinct advantage over the RGB color space. A quick example of this is to apply Unsharp Mask to only the black channel. A lot of times this will sufficiently sharpen the image without even touching any of the color channels, therefore reducing any potential for superfluous noise, grain, etc. There is no black channel in the RGB color space, so sharpening will always sharpen the color information in an RGB file.

Color management is a big hassle for anyone going to print, but it can be managed with a little bit of understanding and time. There are a couple great books on the subject. Even if you are just trying to print photographs to a photo inkjet printer, it is well worth your time to set things up properly. Believe me, you will save time and money in the long run. A couple good Photoshop books dealing with the subject are:

Professional Photoshop: The Classic Guide to Color Correction (Dan Margulis)

Real World Color Correction (Bruce Fraser)

February 11, 05h

Great Article! Coming from web this is a great insight to the world of print, and the differences between the two. Will be most helpful if the need ever arises to create print based versions of web formated material.

Narayan says:
February 11, 10h

I’ll second the recommendation on the Bruce Fraser book. If I have to work with a web designer on a print job, I bring that book along so I have a handy set of diagrams to show disillusioned web geeks before they get too disillusioned at their first press run. :)

Adobe used to include a book with their professional applications and, like most things, they sell it separately now. The title listed by Amazon is “Official Adobe Print Publishing Guide.” I’ve used the older versions for prepress classes I’ve taught, and it’s by far the best-described and most concise guide to the printing process.

In regards to color management systems, I’d have to disagree with you, Dave, I think even web folk who do the occasional print job would benefit greatly from one. For photographers who commit their edits to photoshop layers (as opposed to using adjustment layers), such systems are an absolute must. If you work primarily off a PowerBook it may not make much of a difference because of the variables notebook screen viewing angles bring to the equation, but a hardware-calibrated monitor and a decent printer profile will ensure that what you see on the screen is what you’ll get when you print, be it on a color inkjet at home, a Fiery at Kinko’s, or an offset press. And even if you don’t print—it’ll ensure that what you see on the screen is an appropriate baseline for what other monitors will muck up in either direction. Very basic hardware calibration devices (I’d recommend the Gretag-Macbeth Eye-One Display 2).

Also, I know _plenty_ of people at service bureaus and press houses who work in LAB instead of CMYK or RGB, and I fall into that camp. I don’t see the sense in throwing out perfectly useful information before working with it. The real important part is to understand how transformations between color spaces take place and how to handle the results of such transformations.

The single best advice I can offer for web people doing offset print work is to work with a good and patient printer or hire someone at a service bureau to help you prepare your work for print. You’ll learn a lot in the process, get great results, and—most importantly—garner some major respect for those who cut their teeth in print :).

Josh says:
February 11, 10h

Thank you for writing such a great article. I have always been confused by all this crazy print talk that I hear my print designer friends talking about. This article is one of the best I’ve seen yet for web designers who need to get into print.

Craig C. says:
February 11, 11h

Mike touched upon this in comment #5, but I thought it was worth reiterating: know about gray balance. Cyan is visually the weakest color, and so to get colors looking just right your cyan channel will usually have to be stronger than the others. A neutral gray will have a 5:4:4 ratio (or 6:4:4). If all three colors are the same screen, your midtones will tend to look too warm or muddy because yellow and magenta are so overpowering.

February 11, 11h

Thanks for the great advice Dave, and for putting in the time to share it with us. This is one of those frustrating issues that I always seem to muddle through and am never really sure how I got there in the end. This clarifies so much, and at least I now know that I’m not alone out there…

February 11, 12h

Great job on this article. I’ve only had to do a few print jobs, but I’m always overwhelmed by all the variables and difficulties that arise. Your suggestions will help me keep them to a minimum.

Susanna says:
February 12, 08h

Thank you for writing this article. It wasn’t so long ago that I was frustrated by a dearth of advice for digital artists who need to understand the print world. Every online article, every book I came across was written for print designers who wanted to adapt their skills to the web.

I never formally studied print, but I need to do it occasionally as part of my job. I picked up some tips and lingo from my traditionally educated graphic designer friends, but still feel like every print project I create is a crap shoot: I never really know what I’m going to end up with once those files come out of the printer.

I’ve managed to create some passible posters and brochures, but I’ll still take the screen over the page any day. At least I know how to control that environment.

r0ss says:
February 12, 10h

Real world Adobe Photoshop CS : industrial strength production techniques / David Blatner, Bruce Fraser

This is the same author as a book mentioned earlier. It’s fairly recent and up to date. I picked it up at the local library recently and learned a LOT from it. This book is all about choosing and using the correct color settings/mangement. One of the very first chapters is devoted to it and explains it very well. It also covers everything else very well in minute, easy to understand, detail.

Best photoshop book I’ve seen and I’d recommend it to any designer print or web.

Pete says:
February 13, 04h

If you venture into print the Pantone book will become your new god, although I can’t speak for systems in use outside of the UK. Love it. Cherish it and for Pantones sake don’t leave it lying around on your desk.

Now, two further points to add. Pantone colours come in two variants (there are others but lets not complicate things here), a “U” and a “C” suffix. This shows you what the colour will look like on coated paper (glossy, shiny, whatever) which is our “C” and uncoated (er… not shiny), “U”. Colour will always look different when printed on different materials which have different asorption rates.

As for Mike D’s point #3 above he’s spot on about black not just being black, although everyone has their own ideas about what makes a good black. We tend to go with C40, K100 but that’s my workplaces preference.

One thing designers are never taught and repro people like myself have to know is trapping, where colours overlap to allieviate fit problems on the press. If you find the time to understand this and apply it we in repro will not only love you forever but beg to have your children.

February 13, 06h

Good article, Dave, it’s nice to see someone trying to further the education of web designers to help them stretch out their creative muscles into new territory.

That having been said, I feel very lucky in never having had a printing mishap. I started out in the print world back in ‘97, moved almost solely to web design in 98-99 and I’ve been doing about 90-10 since. (90% web, 10% print).

Whenever I’ve had to print for a client that already has an established printing firm, I always establish a relationship with them and ask them what their ideal PS color settings would be. They’re usually pretty helpful about it, and most will give you small warnings about which colors/situations may give you errors.

I’ve had work printed on book covers, magazine inserts, magazine articles, vinyl banners, full-size movie posters, coffee mugs, martini glasses, you name it. Throughout all of that, I still have yet to find the disastrous color shift problem that I pull my hair out worrying about every time I need to print something.

I guess my only advice is to establish contact w/the printer and ask them their advice for accurate color representation between your setup and their output.

I know there’s a LOT more to it than that, but… maybe you’ll get lucky like I have?

Anyway, keep up the good writing.

February 14, 03h

sRGB is not the bad egg people seem to think it is. If you look at the various color spaces in the mac Colorsync utility, sRGB falls only a little outside SWOP, whereas Adobe RGB 98 contains colors that can never be printed on press. Adobe RGB 98 is good for archiving images because of its larger color space, but for printing, sRGB will give fewer headaches. Saying it is limited is, well, limited. Depends on what the ‘limit’ is, and cymk press is VERY limited.

check out the colorsync utility, and compare various colorspaces, and get a handle on rendering intents, and you will see why color reproduces the way it does sometimes, in inkjets, dye subs, offsets, etc.

February 14, 06h

Yeah, I just learned all this stuff the hard way myself. Put together a 444 page product catalog at work and started with everything in RGB. Over 2,000 photos, most of them from random vendors, and the majority were RGB images.

I asked the printer about this. “No problem!” they assured me. Their RIPping software (converts images to the format needed for the plates) would handle RGB to CMYK just fine. We gave them prints from our own color profiled Epson 2200 for color matching.

Well, the wet proofs came (actual sheets from the printing press) and they looked like crap. They swore it shouldn’t be a problem, but when I mentioned that everything was original in RGB they jumped all over that like it was most likely the problem. Ugh. I think they finally ended up converting everything to CMYK themselves. The final output looks nice, as long as you don’t compare it side-by-side with our original Epson proofs.

Anyway, I learned my lesson: everything will be in CMYK before it goes to the printer from now on. Thanks for the great article Dave!

February 14, 06h

A site I’ve had bookmarked for a long time now is http://www.prepressure.com. The content may not all be fully up-to-date (e.g. no mention of InDesign) but there is a good explanation of a variety of things (including trapping and knock-outs).

I originally got this link from a friend of mine who has been a print designer for years (including repro!). I haven’t read it all myself yet since I haven’t had the time or need to do so until recently.

I’d like to thank Dave and all people who have commented - I have to do some print work in the coming weeks and all the tips will come in handy.

February 14, 06h

Oops, forgot to add the link to an article explaining a fairly new technique in printing called “index color”. If you ever come across the term, you’ll now know how it works ;-)

http://www.screenprinters.net/articles/index.php?art=25

Mike D. says:
February 14, 08h

robert: Agreed that sRGB is closer to SWOP, but that’s only because it’s so limited. My assumption of why people would work in RGB in the first place is that they may be outputting the work (as final output) to a computer/TV screen for another purpose besides print. If this is the case (or if archival is the case, as you say), then sRGB isn’t the best choice.

But sure, if you just want to start out with as limiting of a colorspace as possible, then sRGB is your winner. But then again, if that’s the goal, why not just start in CMYK?

Meredith says:
February 14, 09h

Wow, just in the nick of time; I just got my first really large print commission (for a 24x36 poster from a local restaurant!) so this will help out a lot! I knew about curves & channels & all that back when I worked at a newspaper, but I never had to work with color on such a large scale until now.

Thanks!

Between you & Cameron’s latest entry, I think it’s gonna look pretty good as far as quality is concerned!

-Meredith

Derek says:
February 14, 09h

Kudos, Dave!

I’ve just come back from my first major print design job (client needed the end product, I dealt with the printer), and it was a tiring process matching the colours on the site to the pantone colours that the printer had.

Great article and resources.
Bookmarked.
Thx!

rachel says:
February 14, 10h

Well. I am a designer that started in print and am working on my mastery of the web.

Just thought I’d add some input, seeing as I have about 20 years of print experience.

I only quickly skimmed your article, but the thing I saw that immediately struck my attention was the section on color correction.

Color correction is an art in and of itself, so CYMK newbies should tread cautiously around that one. And definitely not something that can be explained well enough on one web page. Although I laud your efforts.

So here’s my tip: spend more than $50 on a good color printer. Get the best your wallet can afford. Color should and can be fairly accurate from your screen to your in-house color proofs (not the ones you’ll get from the pirnter, but what you want to produce before turning your precious files over to the hairy slob who doesn’t like to look you in the eye in the prepress department at the printer… enjoy… )

But I digress. Get an Epson if you can afford. They are the kings of color and yeah, well the supplies are expensive (you can find good knock-off cartridges at carrotink.com)… but damn the color is good. I put my Epson proofs against digital proofs (and when they were still making them, matchprints) and it was amazingly close.

So, calibrate your monitors, boys and girls, buy an Epson and save yourself a HELL of lot of time and trouble trying to master color correction when all you want to do is get the @(*&$&# file to the printer so you can get PAID.

Over and out,
Onward and sideways —

R

February 14, 11h

CMYK is the bane of digital print artists and will drive you crazy—proceed at your own risk. This statement should included in a popup before programs like photoshop will execute. Heh. Really great article, it helps, but for now there is no real solution aside from trial and error. More errors than most for color matching.

31
Ron says:
February 15, 05h

Just one comment on setting up your Pantone swatches in Illustrator:

Illustrator has several palletes of Pantone swatches already built in.

They can be accessed under:

Window > Swatch Libraries (Illustrator 10 for Windows)
Spot colors are referred to as Pantone Solids in this menu, and are available for coated, matt and uncoated finishes. Which Pantone solid swatch set you use is not as relavant as making sure all of your spot colors come from the same set (otherwise, Pantone 186 from the coated set will print as a different plate as 186 from the uncoated set).

In any case this should save you from having to set up “approximations” of Pantone colors as custom swatches.

32
Greg says:
February 15, 11h

You’ve completely succeeded in reminding me of one of the reasons WHY I went into web design instead of print. Besides the vast pay differences.

:)

To be fair though, I never had an interest in print, just bored me to much.

Great article though!

33
Steven Keith says:
February 16, 06h

This is great. There is a gentleman at the company I am with that wrote something that I feel is a great companion to this.

http://www.capstrat.com/cs/insight/lunchandlearn/Graphics_handout.pdf

February 16, 10h

Thanks, Dave, very interesting article.
Only two little thoughts:
1. Print is fun for somebody, who is used to screendesign, because for first time you can be *pixelperfect*.
2. Print is horrible for somebody, who is used to screendesign, because of the *wysosinwyg*-factor (what you see on screen is not what you get).

35
Tom Creighton says:
February 17, 07h

Just to chime in with my own $0.02 - having moved into print from a largely web background: ALWAYS start in CMYK if you’re working on a print job.

The amount of headaches you’ll avoid by not having to do color correction at the end of the job: numerous.

Also, as noted above, with a properly color-calibrated computer and monitor, there really won’t be any difference at all between what you see on your screen and what you end up with.

This may be truer of more recent software (Photoshop CS), and having a very crisp and colour accurate monitor helps IMMENSELY. I use a LaCie Electron Blue - the colour matching is almost spot on.

36
Jeroen says:
February 18, 04h

Wow Dave, that’s a pretty complete primer for any webdesigner going to print. To add some more cents to the confusion, multichannel is not the only (or best) way to get spot colors in Photoshop; duotone or tritone is more widely used in spot color images (photos mainly). As I didn’t see anyone cover this in the comments above, let me try.

Basically, you translate an RGB photo through LAB to a greyscale one, or start with a B&W photo in the first place. Converting to greyscale with LAB and the selection of the lightness channel usually gives better results (contrast and lightness) than ‘image>mode>greyscale’. Having the greyscale image, you select ‘image>mode>duotone’. In the resulting menu, you can choose the correct spot colors (PMS or other), and tinker with the translation curves.

What happens is that a given density in the greyscale image gets translated to another density for any spot color you specify. For instance, 30% gray (input) can end up as 80% PMS361 and 20% PMS432 (output for a duotone in these PMS inks).

37
nicole says:
February 23, 05h

Excellent article for those just starting off in print! Some comments: Your article almost implies that Photoshop does not have Pantone colors and you must use Illustrator to see them. However, when you are in the color picker in Photoshop, click on the “Custom” button (right below “Cancel”) and then you can choose Pantone colors!

Trapping�— if you have a good printer, they should take care of trapping for you. For those who don’t know, trapping is the process of making two colors overlap (very) slightly so if they do not line up exactly when printed (remember, each color is on a separate plate), there is no gap visible. Photos do not need to be trapped�— but two flat colors right next to each other do.

Duotone (and tritone, etc.) vs. multichannel�— which one you choose depends on what you need to do.

When you use duotone, you can not edit each channel individually except for controlling the curve associated with it. Duotone is almost exclusively for photographs, generally for adding a color cast to a black and white photo or to extend the range of tone of a black and white photograph. For instance, high-end black and white photography books are often printed as quadtones��— black and three shades of gray. You must save your duotone as a photoshop eps file for it to separate properly, especially if you are placing it in Indesign or Quark Xpress.

With multichannel, you can draw, paste, and otherwise edit each channel individually. You have to use multichannel if you need to use CMYK and you want to add a spot color. For a multichannel file to separate properly, you must save it as a DCS file, and I highly recommend that you contact your printer before creating a multichannel file.

In general I recommend finding a printer and talking to their production people early in the project. Show them your proofs (or email them a pdf file) and ask if they see anything that might be a problem. Ask them what settings they use in Photoshop to convert from RGB to CMYK.

Many printers only provide digital proofs nowadays because they’ve gotten very accurate and because of changes in printing technology. They used to have to output film, then use the film to burn the plates for the press. “Matchprints” were made from the film, and film is expensive. Now there is “direct-to-plate”, meaning there is no film, hence no way to make a matchprint. Even if your printer does still use film, they might still only offer digital proofs.

Regarding what’s on the screen not matching what you print��— I’ve always done a rudimentary monitor calibration that gets it close enough. In Mac OS 9, I used to use the Adobe Gamma control panel that came with Photoshop. In OS X, you can just go to System Preferences -> Displays -> Color and click Calibrate. It will take you through some steps to roughly calibrate your monitor. If you are particularly ambitious, you can set up two monitor profiles, one for print work and one for web work, and switch between the two.

Although I used to work in print production, about 80% of my job now is web design. But I still think in CMYK. I hope this helps!

Anastasi says:
December 14, 18h

CMYK and RGB are two different systems for creating color. Generally CMYK is used by commercial printers and so most print materials need to be exported in a CMYK color mode.