Printing has changed more in the last 50 years than it has in the previous 200–and with each change, there are new opportunities and challenges. Let’s look at the evolution of the digital printing era, some of the challenges faced, the opportunities it has created and where we are today.

With film, we refined what we were doing to the point where we could print some high-quality images with resolutions of 200 – 300 LPI. We had good proofs that accurately represented what was expected on the printed sheet. Then, we moved into the digital era that opened up many new doors.

Some new companies emerged on the scene that were not printers, but were computer savvy and saw great opportunities in the printing trade. Creo and Presstek were a couple of the more notable ones. These companies worked on being able to take the digital image from the computer and accurately transfer it to a plate (CTP) without the need for film. They also transferred information from the computer directly to the press (DI).

In the beginning, they worked with a “spark technology” that gave us an image that didn’t have the sharp, clean dots and nice rosettes that we were accustomed to with film. Instead, the dot was rather splattered and had fuzzy edges to it.On the upside, we had pleasing colour, which was fine for some work, and we had eliminated film, which was both a time saver (no stripping required) and money saver (the cost of film). It also gave us the ability to make changes in copy at the last minute and still deliver the job on time (instant four-colour process printing). We soon changed from the spark technology to laser technology, which gave us a much sharper and cleaner dot on the plate.

COMPARING CTP DEVICES
At this point, the plate manufacturers were working hard to make good plates that worked well with the CTP technology. In the beginning, the CTP plates were expensive and sensitive to external conditions. If everything wasn’t right in the imaging and processing stage, you’d have many problems on the press.

Two types of plates and platesetters (CTP devices) emerged here–thermal plates that aren’t light sensitive and are imaged with IR radiation at 830nm with an external drum device, and the light-sensitive photopolymer and silver halide plates, which are imaged with an internal drum device. The photopolymer violet plates are imaged at 400 – 410nm and the silver halide at 488 – 532nm.

The advantages of the thermal plates included a good, sharp, stable dot with a tonal value change less than 0.5% during running. Because of its stability, it’s a good plate for FM (Stochastic) screening and it will usually give you longer runs. The main advantage of the violet plates is the cost–they’re less expensive than thermal plates.The dot on these plates is not as sharp as thermal plates and noticeable sharpening of the dot and tonal value changes are apparent the longer the run is. This plate has a tonal value change of more than 1% and is, therefore, not compatible with FM screening. The silver halide plates are very dirty to work with and are also high maintenance.

At the same time, technology was changing quickly in the prepress area as there were both challenges and great opportunities in the creation and manipulation of images. Companies like Corel, Quark and Adobe were leading the way here. Some of the early challenges were banding in vignettes and moirés, especially in flesh tones and rough edges on letters and images. These have long since been resolved by changing dot shapes, image resolution and in some cases, screen angles.

ACCURATE PROOFING AND PRINT COLOUR MANAGEMENT
Once we were able to do away with film, a whole new problem came about. Those good, accurate proofs we used to produce were made from film, so we could no longer give the customer an accurate proof; also the press operator didn’t know what the job would look like. He/she would sometimes have an original or previous copy to check against, but there is less dot gain with CTP than with film, so he/she would try to do colour correction on the press to match the previous copy. The problem was, the operator didn’t have a hope of being accurate.

So,we had to find a way of using this digital information to create accurate proofs.
The first reasonable digital proof was the Iris. It gave us a good idea of what could be expected on the press, although it had a very light blue screen throughout the background and wasn’t as accurate as we had become accustomed to with film.

Better software programs were developed where ICC profiles could be put in place for output to better printers. (HP and Epson are the dominant ones at the moment). Many of these ICC profiles were “canned” profiles that didn’t match the conditions of the print shop, or work in the same colour space as the presses in that print shop.Any good, accurate proof has to work within the same colour space that the printing press is able to print, so print colour management is required to tie everything together. There are many steps to proper print colour management, and every device used in the production of a printed piece has to be hallmarked and calibrated to set standards. Identifying and documenting these standards is the first step.

The following should all be taken into consideration: CTP device, type of plates used, proofing device, type of proofing material, dot shape, line screening, AM or FM screening, press type and conditions, inks, paper, blankets, dampening solution, target densities, LAB, dot gain values (are they ISO, GRACoL or customer-defined standards?), measuring devices (densitometer, spectrophotometer) and device settings (status T, DIN 16535, D50, D65) and so on. Once this is done, the CTP and proofing devices can be calibrated to base standards through computer programs. An ink weight profile is set for the proofer and a linearization curve is applied to the platesetter. Measurable control elements should be put in place to assure these device settings have not changed. We next fingerprint the press by running a test form with linear plates to the defined inking standards. Once this is done, we can measure the elements of the test form and compare where we are in relation to our dot gain and grey field targets. Computer programs today will allow us to feed in this information and calculate what changes have to be made to hit our predefined targets. A process curve is then made to alter the image on the plate so that the printed sheet meets the target standards.
At this point, we can extract the colour space information from the test form to create an ICC profile. This digital information defining the colour space that our press is able to print in, is then put into the program that sends the information to the proofer. We now have our printing press and proofer working in the same colour space so we’re back to the point where the proof and the printed sheet match. We have a predictable result that both the printer and customer can rely on. This ICC profile can be sent to any agency, design house or anyone that can make proofs for you, so the result is always the same.

OTHER DIGITAL OPPORTUNITIES
We’re beginning to see more “soft proofing” (i.e., sending the customer the proof in a digital format to view it on a computer monitor. This is not quite as accurate as a “hard proof” because we’re transferring CMYK information to an RGB output. The important factors here are that your ICC profile is applied to the customer’s program and that the viewing conditions are controlled so one can view it properly).

Another opportunity that came from digital was the ability to create CIP3 (PPF) and CIP4 (JDF) files that have allowed us to communicate with and between all the devices in the print shop, prepress, press, post press and beyond. Digital image information is now used at the press to preset the ink fountains so that when a new job is put on the press, accurate colour to predetermined values is achieved in a minimal number of sheets.

There are also programs that will update compensation curves for this information as conditions change (i.e. different inks, paper etc., to keep the inking profile as close as possible to perfect when a new job is loaded. A full makeready on a large multi-colour press can now be done in less than half an hour).

Post press devices are also able to use this information for setup. There’s no longer a setup at the cutter for jobs with many cuts. What used to take days and weeks to produce is now produced almost instantly.Today, we can receive a job in the morning, and deliver it later that day. The important thing to remember here is that you have to set standards and calibrate everything to those standards to get a consistent and predictable result.

THE CHANGING WORLD OF PRESSROOM CHEMISTRY
If you believe that the printing industry has changed dramatically in the past 50 years, consider the fact that supporting industries must also change to facilitate the success of print shops today.

Pressroom chemistry is no exception. With the sophistication of printing presses, papers and other pressroom staples, has come a whole new set of problems relating to production-calcium carbonate, dot spread, linting, premature plate wear, pH and conductivity, problems with rollers, fountain solutions, and so on.

Over the past several years, pressroom chemical manufacturers have plotted a bold course of innovation through research and development breakthroughs. Each time a new problem developed in the pressroom, chemical manufacturers were there–not just with chemistry solutions, but with production solutions as well.

When I joined Commercial Litho Plate Graining in 1951, the shift to offset printing using aluminum plates as opposed to zinc plates was already underway. This was a major turning point in the industry at that time, so we devised a breakthrough processing method that made our company’s wipe-on plates the most successful in North America.

Today, chemical products for the pressroom number in the hundreds and include fountain solutions, alcohol replacements, plate cleaners, protective gums, solvents, silicone and other specialized products. They’re all formulated specifically to solve common problems that occur in the pressroom. With Unigraph International, for example, every one of our products is also pre-tested under carefully controlled conditions in our own manufacturing plant. They must meet the highest quality of the printing industry and cover every conceivable machine-sheetfed presses, heatset web presses, coldest newspaper web presses and so on. But, equally important these days is 24-hour technical support that helps printers reduce one of the costliest problems in the pressroom–downtime. To share this problem-solving expertise, field technicians must keep pace with virtually every emerging new technology in the industry. And this includes the ongoing realization that we must create products that make less of an impact on our environment; in other words, biodegradeable “green” products.

As the printing industry faces the challenging CTP and digital eras, pressroom chemical manufacturers will continue to be at the forefront of changes that reflect the rapid pace of our industry’s thirst for new technologies. Look at it this way: you might drive the most expensive, technically sophisticated car on the road, but see what happens when you start running out of motor oil for your engine or coolant for your radiator!

Are you using the right deglazer for today’s press problems? A good brand-name deglazer should do the job, right? Not necessarily! With all the changes to paper in the last 10 years, it’s crucial to understand exactly what’s happening on press and what a deglazer should be doing for you.

Let's examine glaze
It can form and accumulate from 3 primary sources:

1. By-products from the fountain solution and/or an alcohol substitute.
2. Ink.
3. High-filler-content papers.
4. A combination of the three.

A good deglazer should be able to clean what is water soluble (1 and 3 above) and what is solvent soluble (2 above).
One of the biggest changes in our industry has been the introduction of alkaline-based paper to replace acid-based paper. There are many reasons for the change from environmental concerns in papermaking to an ongoing trend to increase sheet brightness. With these changes, printers have had to address many other issues.

Calcium carbonate
Here are some of the most common problems caused by high-filler-content papers (calcium carbonate):

1. Plate blinding or ink walking off the plate (dot blow-out).
2. Premature plate wear.
3. Poor ink transfer down the ink train.
4. Inconsistent ink/water balance causing color variation throughout the press run.
5. Reduced drying time.
6. Hardening of rollers.
7. Premature roller wear.
8. Picture framing on the blanket, especially when running a short sheet.
9. Build-up on the impression cylinder.

There is really no way of stopping calcium from coming off the paper. Let’s go through what happens as paper passes through your press:

1. Calcium (whiteners, chalk and fillers) leaves the surface of the sheet and is released onto a humid blanket.
2. From the blanket, it transfers to the plate and dissolves from a powder to a liquid because of the fountain solution on the plate.
3. The liquefied calcium touches the dampener form and ink form rollers.

On the dampening side, it transfers from the dampener form back onto the pan roller and into the tray, and then back into the re-circulation unit. For those without a re-circulation unit, it sits in the tray and accumulates.

On the ink side, it touches the ink form rollers and starts to contaminate the rollers all the way up the ink train.
When the press is not running, the calcium in the rollers dries and then crystallizes.

What’s the result of all this? You now have a glaze that is locked into the pores of your rubber rollers due to the crystallization of the calcium. This hardens the rollers, causing not only a poor ink transfer (resulting in a low-quality print), but substantially decreases the life expectancy of your rollers.

Take preventative measures! By using Uni Enviro Deglazer as part of a preventative maintenance program you can eliminate this from happening.

Procedures to decontaminate and maintain rollers and blankets.

1. Remove ink from ink rollers and blankets using your regular wash-up solution.
2. Mix Uni Enviro Deglazer 70/30 with hot water (70% Uni Enviro Deglazer + 30% hot water) in a wash-up bottle. Apply the mix in the ink train. Engage the dampening system while doing the procedure in order to decontaminate the dampening form roller.
3. Apply 8-10 ounces of the mix to each unit continuously.
4. Let the mix run for 15 minutes, then rinse off. (To be done as the FIRST major decontamination).
5. Only use this much product on a first application when a major decontamination is necessary. For on-going preventative maintenance, use 4-6 ounces of the 70/30 mix of Uni Enviro Deglazer and hot water after every shift. If a job is continuing into another shift, try to perform this procedure after the end of that shift.

What is fountain solution?
The dampening system on a lithographic sheetfed press applies a water-based dampening or fountain solution to the printing plate before it is inked. Dampening solutions keep the non-image areas of a plate moistened so that they will not accept ink, and are applied to the entire plate.

The non-image areas of the plate, which are made that way by adsorbing a thin film of gum arabic to them during platemaking, are hydrophilic (water loving) while the image areas are hydrophobic (water repellent). The desensitizing film on the non-image areas wears off gradually as the plate continues to run on press, so the chemicals in the dampening solution replenish the desensitizing film. Ink, plate, press speed, paper, temperature, and relative humidity are the principal factors that influence the need for various dampening solutions.

Fountain Solution
Fountain solution is a water-based mixture specially formulated to dampen lithographic printing plates before they are contacted by the inking rollers. In concentrated form, it is commonly referred to as fountain concentrate, fountain etch, or just etch. Most fountain concentrates today contain synthetic desensitizers. Very few manufacturers still use natural Sudanese gum arabic because of its cost. The term dampening solution is used for the diluted etch.

Fountain Solution Ingredients
Fountain solutions are usually sold as concentrated solutions that are diluted with water to the proper concentration. Most one-step concentrates already contain a natural or synthetic gum, an alcohol substitute, and other essential ingredients, and simply require being diluted with water. With two-step concentrates, the first step generally contains all of the ingredients except the alcohol substitute, with the alcohol substitute added as part of the second step. Although this extra step might be an inconvenience, it permits the press operator to control the alcohol substitute concentration better.

The proper mixture of chemicals in the solution is critical for quality printing. Though there may be many chemicals that make up a given manufacturer’s dampening solution concentrate, the general ingredients common to most are described below.

Composition of a Fountain solution
Fountain solution composition varies for a number of reasons. Most dampening solutions, however, are acidic, with a pH of 4.0-5.5 being typical. The dampening system itself also influences the composition of the dampening solution. For example, some dampening systems require a specific percentage of alcohol (or alcohol substitute) due to the method of applying the solution to the printing plate. Sometimes, in a conventional dampening system, the use of such an additive improves print quality although its presence in the dampening solution may not be essential.

In general, a dampening solution will consist of the following ingredients:

• Water, with minimal impurities.
• Acids or bases, depending to a large extent on the ink being used. Acids used include phosphoric acid, citric acid, and lactic acid.
• Gum, either natural (gum arabic) or synthetic, to desensitize non-image areas—that is, to make them prefer water to ink.
• Corrosion inhibitors, to prevent the dampening solution from reacting with the plate. Magnesium nitrate is sometimes used; it also acts as a scratch desensitizer and buffer (a substance capable of neutralizing acids and bases in solutions and thereby maintaining the acidity or alkalinity level of the solution).
• Wetting agents, such as isopropanol or an alcohol substitute, which decrease the surface tension of water and water-based solutions.
• Drying stimulator, a substance—such as cobalt chloride—that complements the drier in the ink. Drying stimulator is an additive that is used only if ink is not drying fast enough. Typical concentrations are 1-2 oz. of stimulator per gallon (8-16 ml per litre) of dampening solution.
• Fungicide, to prevent the formation of mildew and the growth of fungus and bacteria in the dampening system.
• Antifoaming agent, to prevent the build-up of foam. Foam can interfere with the even distribution of dampening solution on the dampening rollers.

What is pH?

• It measures the acidity or alkalinity in a solution
• The pH scale goes from 0 to 14, with 7 being neutral.
• A pH lower than 7 is acidic
• A pH higher than 7 is alkaline, or basic.
• Measured on a logarithmic scale, for example:

pH 5 solution = 10 X more acid than a pH 6 solution pH 4 solution = 100 X more acid than a pH 6 solution

What is conductivity?

• A solution’s ability to transmit an electrical charge; to measure conductivity, one measures the number of ions in a solution. The higher the ion concentration, the higher the conductivity degree.

I hope this has given you a good overview of the necessary parts in a good fountain solution, and I leave you with some of the advantages of modern fountain solutions: prevention of printing plate surface oxidation; prevention of foaming in printing fountains and in dampening systems; curing of micro scratches on plate surfaces; lubrication of blanket surface; resistance to change of acidity in fountain; formation of protective film on plate surface; clean roll up; and minimum start up waste.

Making the transition to a low-VOC wash doesn’t have to cause undue sacrifice or frustration. The following steps can eliminate some of the problem areas and make the changeover successful.

VOCs (Volatile Organic Compounds) are unhealthy for many reasons—they can harm the environment by helping form smog, which damages crops and forests in addition to being harmful to lungs. Some blanket washes also contain chemicals called Hazardous Air Pollutants (HAPs), which may also harm human health and the environment.

By using blanket washes containing fewer VOCs, you can significantly reduce the impact that your printing operations have on employee health and the environment. You may also be able to reduce your regulatory requirements. To find out the VOC content and other components of your current blanket wash, ask your supplier and check the product’s Material Safety Data Sheets (MSDS). Suppliers can recommend substitutes containing less VOCs.

Press Washes: Solving the problem
History tells us that the best press washes are those that break down and remove ink quickly, evaporate fast, and are easy to use. History also tells us that these traditional washes typically contain 90% to 100% petroleum distillates (VOCs).

Today’s environmental climate and the issuing of increasingly stringent regulations are creating a situation where these traditional, high-VOC washes are no longer acceptable. The current target for low-VOC washes is that they contain less than 30% VOCs (by weight), which equates to approximately 2.5 lbs. per gallon.

The obvious question is how do we move from efficient, high-VOC traditional washes to the more environmentally acceptable low-VOC products?

Unfortunately, none of the alternatives are perfect. The surfactants typically used to formulate emulsion-based washes, if not properly removed, can build up on rollers and blankets, causing poor ink transfer, stripping, and emulsification. The vegetable oil washes often require a rinse step, leave a greasy residue, and are also slow to evaporate. With wash-ups sometimes taking place up to 15 times a day, this can have a substantial impact on production costs. Include periodic deep cleanings using a wash such as Unigraph’s Color Change Wash Setp 1 and 2 to eliminate surfactant build up.

Washes containing exempt solvents are efficient and sacrifice little in productivity, but they present problems and frustrations for the press operator. If you attempt to go from a solvent-based wash to a low-VOC alternative overnight, the most practical and cost-effective approach is to do the changeover in several steps. While reducing VOCs is critical, cost of restarts, paper, and quality of printing must all be considered.

How to make low-VOC washes work
Making the transition to a low-VOC wash doesn’t have to cause undue sacrifice or frustration. The following steps can eliminate some of the problem areas and make the changeover successful. While this procedure doesn’t completely eliminate VOCs, it significantly reduces them without sacrificing cost effectiveness and print quality.

Choose a good quality, low-VOC wash from a reputable manufacturer.

Begin using on rollers. Periodically deep clean them with a traditional two-step colour change wash to eliminate surfactant buildup.

After a period of successful use on rollers, begin using as a blanket wash, always following the manufacturer’s recommended procedures. In cases of unusually difficult cleaning, a traditional wash should be used.

To help avoid problems, continually monitor rollers and blankets. Look for signs of surfactant build-up, such as greasy residue, ink emulsification, poor ink transfer or slow cleanup.

While this procedure does not completely eliminate all VOCs, it significantly reduces them.

To date there are no perfect low-VOC washes. But with a strong commitment and an understanding that these washes perform differently and require more attention, a pressroom can effectively eliminate a substantial percentage of VOC’s from its press washes without sacrificing efficiency and print quality.

The development of higher-performance, more effective low-VOC washes is always continuing—find out which one is right for your shop.