A Book Review by Ray Maxwell
This is a review of a book by Rick McCleary titled “CMYK 2.0”. However, to fully appreciate the importance of this book I would like to give some history of the printing industry and background of how the printing industry has arrived at the methods described in “CMYK 2.0”.
If you have ever been involved in any aspect of reproducing a photograph on an offset press, you should read this essay and this book. This applies to photographers, designers, prepress persons and printers.
CMYK 1.0 or how it used to be…
When I started work in 1997 for a major manufacture of electronic prepress hardware and software, things were very different than they are today. I attended a national meeting of printers and prepress people. I attended a seminar on “Color Reproduction”. I stood up in the meeting and naively asked how many people attending the seminar were using color management. One person in the room held up his hand. I actually got stern looks from other people in the room like I had taken their mother’s name in vain. After the seminar the one person who held up his hand came over and introduced himself. He was Dave Reynolds of Litho-Krome, a subsidiary of Hallmark Cards. He was an early adopter of color management that he used it to do very accurate reproductions of some of the best original artwork in the world. He is now a Senior Project Manager at Hallmark Cards. This shows that in 1997 the overwhelming majority of the printing industry was not familiar with color management and some were openly hostile to the idea. So this begs the question of how did this happen and how did they control color during this era.
The time when transparencies and laminate proofs ruled the world…
At this time photographers produced transparencies or reflection prints and gave them to a service bureau or color separator for the next step in the process. A highly skilled scanner operator would scan the transparency (transparencies were preferred over prints). Inside the scanner the film was scanned using red, green, and blue separation filters (many operators did not know this). The RGB data was converted to four channels of CMYK data. Each channels was corrected for the dot gain of the intended half-tone screen and press characteristics. Keep in mind that this all happened inside the scanner and was hidden from the operators. A typical drum scanner cost $50,000. The data was then sent to a RIP (Raster Image Processor) and it was converted to a half-tone screen and a bit map file was produced that has nothing by ones and zeros in it. This bit map file is then sent to an imagesetter that exposes litho film. The litho film is then developed. You now have four pieces of litho film that are clear with a collection of dots that represent the tones of each color channel. Next, each piece of litho film is matched with the corresponding Cyan, Magenta, Yellow or Black proofing material and placed in the vacuum frame and exposed to an arc lamp. After each piece of proofing material is processed it is then stacked and laminated together with all of the color layers (CMYK) and a piece of the printing paper. You now have a laminate proof. The material to produce this proof is very expensive (about $70 U.S. for a 20” x 30” four up proof). It is also very labor intensive to perform all of these steps.
The scanner operator would now go to a 5,000 degree K viewing booth and compare the original transparency and the laminate proof. Keep in mind that the transparency could reproduce a much larger color gamut than the laminate proof or printing press due to the inks used and the fact that both of these produce a reflection print. If the scanner operator did not like the rendering or the conversion from transparency to proof, they would make corrections and repeat all of the steps again.
If the color separator and client were happy with the rendering of the transparency in the proof, the service bureau would send the four litho films and the “contract proof” to the printer.
The printer would then burn four printing plates by placing each litho film in a vacuum frame with a light sensitive printing plate and exposing it using an arc lamp. The plate was then processed. Each printing plate is then mounted on the offset press in the corresponding Cyan, Magenta, Yellow, and Black printing unit.
At this point, it is the job of the press person to adjust all of the parameters (there are many) of the press to match the “Contract Proof”. This is very high art and craft. These people are very highly skilled. A good press person can move the color of an offset press all over the place in order to match the proof.
Who really controlled the color during this era…
The process control of the color was in the hands of the companies that made the transparency films and laminate proofs and the press operators. The manufactures of the films and laminate proofs have top notch color scientists, and experts in manufacturing process control. They did an enormous amount of research into presses to determine the gamut and sweet spot of the presses used by most printers. They also manufacture a product that is very, very consistent. Their instruments are all spectrophotometers that cost about $10,000 each. The instruments are hand selected by the instrument manufactures to be perfectly matched across the entire media manufacturing company. The readings of instrument used by one of their R&D scientists will match very closely the worker on their coating line who is making the product in another city. They also have very expensive ceramic tile color standards and run an instrument metrology program for all of their spectrophotometers.
The press operators use a densitometer to bring the press to the approximate starting point. They then make the fine adjustments by eye to get a visual match with the contract proof.
CTP changes the rules…
The first major change in the industry was the invention of Computer to Plate imaging systems. The output of the RIP was now sent directly to the CTP imager. This imaged directly onto the printing plate and was ready to mount on the press after processing the plate. This means that you could eliminate the need for litho film. The only problem with this was that there was no litho film to produce a laminate proof.
When I started working in the graphic arts industry, I worked on the Creo Spectrum half-tone proofer. The purpose of this machine was to produce a half-tone proof directly from the digital file without the litho film. I worked with the color scientists at Imation, Kodak, Fuji, and Dupont who all made proofing media for the Spectrum proofer. The Spectrum used the same laser imaging system that was used to image the plates for CTP. In fact you could buy one machine from Creo that would image both plates and proofs. The cost was approximately $500,000 per machine.
The proofer produced a single clear sheet with the four process colors (CMYK) imaged on it. This took about 15 to 20 minutes to produce and you still had to laminate the clear carrier onto the proofing paper. This was a manual process. The media for one 20” x 30” (four up) proof was about $70 U.S.
Remember that up to this time, service bureaus produced scans and delivered four sheets of litho film per page and a contract proof. CTP now eliminated two of these deliverables. Many service bureaus went out of business. Many highly skilled scanner operators lost their jobs. Desktop scanners were getting better and lower in cost.
Inkjet printers get much better and less expensive.
By the year 2000, Epson, Canon, and HP were making very good large format printers. If you put a really high quality RIP ahead of these printers, you could produce a very high quality and consistent proof. However, the inkjet printers have a much larger color gamut and use dyes or pigments that have very different spectral characteristics from the pigments used in offset printing. This means that you must understand and use color management. The good news was the color was very adjustable. The bad news was the color was very adjustable and you need your own instruments to keep the color constant. The cost of the proof produced by inkjet printer is much less expensive than the half-tone laminate proofs. The inkjet proofs have one drawback. They do not use AM screening and do not predict moiré. Many modern printers use stochastic screens on their offset press so this is no longer an issue. Stochastic screens do not produce moiré.
Digital cameras arrive on the scene…
The next blow to accurate or pleasing color was the digital camera. Up to the arrival of digital cameras, photographers were delivering transparencies. There was no doubt about the color that they were delivering. Now everyone wants digital files to be delivered instantly. We all know that without color management, no two monitors display the same color. Since they had driven the separators out of business the industry started asking the photographer to deliver CMYK files. To make top notch CMYK files you need to know the press, the screening used, the paper, and the coating. Most photographers know nothing about these parameters.
What can go wrong with a system like this…
Does the photographer have a good monitor and knows how to calibrate it?
What RGB color space should the photographer use?
Should the photographer deliver CMYK files?
What CMYK color space should he use.
Since many early CMYK files were delivered with improper calibration, many authors and printers recommended removing all ICC color profiles. They believed that all CMYK files were calibrated to image in Matchprint or
Fuji proof or one of the standard laminate proofing color spaces.
What should a designer do with regard to ICC profiles in photographs?
Should a designer do the CMYK separations?
Many printers believed that they would produce a proof that would match their press. Remember that a press operator can move the color all over the map. Where do you set it to make a profile of the press?
As you can see there are all kinds of opportunities for things to go wrong and point fingers at the other guy. So how do we avoid trouble at each stage of the process?
As you can see the “stake in the ground” references for color that was provided by transparencies and laminate proofs are gone. This means that the end users rather than the media providers must do the color science, instrument calibration, measurements, and use industry standards and process control. Every person in the workflow must be competent and understand how to do their part.
CMYK 2.0 gives us a plan of action for each step.
Rick McCleary makes it clear that RGB to CMYK workflow is a team sport. There are many people involved in the process and it is very important that each person knows how to maintain the integrity of the process. He explains the rules for photographers, designers, pre-press, and printers. This is a guide for understanding how to communicate color at each step in the process.
Monitor calibration is an absolute necessity. He suggests that photographers use the Adobe RGB 1998 color space for files that are going to be converted to CMYK. He warns that converting from PhotoPro RGB to CMYK can be very tricky. He is not against using ProPhoto RGB for producing wide gamut inkjet prints. You can make either from your original RAW file. He explains several methods of making a CMYK files and correcting it for reproduction. He also goes through the steps of making a “guide proof” using a RGB printer. He points out that a photographer cannot make a “contract proof”. The printer must do this since he is bound by the contract.
Designers are taken through each step in setting up their software to maintain the correct color while doing placement and page layout.
He also explains the rules for the pre-press and press persons.
I will give you a very condensed example of several methods that can be used for converting to CMYK files.
The simplest method is to use one of the standard files included in Photoshop (such as U.S. Sheetfed Coated) if this is what the printer suggests. You then make minor corrections after the conversion.
The next method is to receive a custom profile from the printer that they supply. You will still need to make minor adjustments after the conversion.
The last method is to find a highly qualified color separator that is familiar with the press, the paper, the screen, and the ink set and have them produce the CMYK file.
The main theme of the book is about collaboration and communication between each member of this team. You must talk with your printer to know how to do the separations.
This is an excellent book that explains each step of the process. It is the rule book for each member of the color team. It clears up many of the steps in using a modern ICC color managed workflow from camera to press.
The final chapter of book gives actual war stories from a Designer, a Photographer, a Digital Wizard, and a Printer. They are from the real world and have been there and done that.
I am so happy to see this book on the market. It is long over due. I really hope the old school will go out and buy this book and move into the twenty first century.
If you go to a printer and he cannot talk with you about color management and ICC profiles, find another printer. You might also suggest that he read “CMYK 2.0”
Copyright 2009 Ray Maxwell