I’ve been following the industry news regarding the continuing important role of offset lithography as an ongoing vital printing technology, and I was pleased to see WhatTheyThink’s addition of a new editorial section on the process.

I found this renewed focus on offset lithography intriguing in light of most of today’s printing industry news revolving around the newer technologies of inkjet, electrophotographic imaging, and other digital printing technologies. The evolution of lithography and its development from an art to a craft to a science is something that I was personally involved with, and I may have a historical perspective of interest.

The promise of offset lithography as a commercial process became imminent in the 1940s when the Lithographic Technical Foundation (LTF) was formed, and eventually became the Graphic Arts Technical Foundation (GATF) in the early-to-mid 1960s and relocated from Chicago to Pittsburgh.

Plan for Plant Audits

Shortly after that, in 1968, I received my Masters degree in Printing Management from South Dakota State University, and I was hired by GATF to join its Technical Services Department. This was the department that developed what became the very well known Technical Plant Audit program.

This was a program where GATF would send one of its technical services representatives into a printing plant to observe methods, techniques, equipment, and personnel, and make recommendations for improvements where they saw problems. The process was not that scientific and based solely on the understanding the representative had about lithography.

My role was to learn how to conduct these Technical Plant Audits and to visit companies to observe their lithographic operations. However, my role became a bit different than just making general observations and providing recommendations. It became to better understand the variables in the lithographic process that made it so inconsistent. Some might recall the expression back then about lithography: “The only consistent thing about offset lithography is its inconsistency.” 

Master Tester’s Toolkit

So, I was to visit plants and actually measure the variable operations on offset presses. In my years at GATF, I traveled the nation and the world visiting lithographic printing plants to measure various components of the process and establish standards related to settings that resulted in the highest quality and most efficient printing. I carried with me a kit including a densitometer, a packing gauge, an ink film thickness gauge, a durometer, a sling psychrometer for testing temperature and relative humidity of pressrooms, and a myriad of other instruments related to measuring the quality of print and pressroom environment. 

I was the first person ever to make measurements of variables such as plate-to-blanket squeeze using a packing gauge. In fact, this process was so new that the packing gauge I was given was a prototype. Eventually, once it was determined that this device worked well in defining and measuring the amount of squeeze required for quality printing using different types of blankets, such as conventional and compressible blankets, the right to manufacture a packing gauge was turned over to Baldwin Technologies. Baldwin then developed the first commercially available packing gauge.

Further, I was one of the first people in the industry to demonstrate and advocate the advantages of color measurement using a densitometer. Press operators were quite skeptical when they saw me coming into a plant and using this instrument to measure consistency of printing. 

“This Is My Densitometer”

They would say things such as: “Do you see this (pointing to their eyes)? This is my densitometer. Don’t tell me that your instrument will do a better job of seeing color than my eyes.” However, once they saw the consistency of a densitometer in measuring color, they often changed their tune, and the densitometer became the standard means of measuring and quantifying color in the printing industry. 

I would also carry a portable pH meter for measuring fountain solution pH, which was determined to be vital in the efficient running of lithographic printing press and particularly as it related to ink drying issues. I used a Shore durometer to measure the hardness of form rollers and distributor rollers, and to determine what the hardness range was for these two types of rollers for the most efficient and best quality printing. I used an ink film thickness gauge to determine the thickness of ink within the roller train, a device that the airline industry used to measure the thickness of paint on airlines because thickness impacted weight. 

On and on I would do these measures in printing plants all over the nation and world. I did this over seven years at hundreds of companies and on thousands of printing press units. These measurements were all carefully documented and then related to solving printing problems and to developing statistical ranges in which the best offset printing occurred.

Sweet Spot for Best Results

At one point I was able to make the determination that approximately 90% of all lithographic printing that met the highest efficiency and quality standards fell within certain quantitative ranges in the areas being measured. I have that data confined to memory. It’s ingrained in my brain. I will never forget it, and I often refer to it when asked questions about settings on lithographic presses. More specifically, the areas I quantified are: 

• Optimal plate-to-blanket squeeze for conventional and compressible blankets.
• Optimal ink film thickness as measured on the last steel oscillating roller on the opposite side of the dampening system.
• Fountain solution formulation and pH.
• Form roller and distributer roller settings.
• Roller durometer.
• Optimal density ranges for yellow, magenta, cyan, and black.
• Light temperature in Kelvins at press deliveries.
• Ink trapping percentages.
• Pressroom temperature and relative humidity.

Knowledge Passed Down

From this data, I generated two GATF technical services reports that documented the recommended quantitative ranges within which the best lithographic printing occurred. One focused entirely on sheetfed printing and the other on both sheetfed and web offset printing. I also wrote an instruction manual for conducting these audits and for recording the measurement data. The electronic offset presses of today have such data programmed into their software.

With all the progress that has been made in offset lithographic printing since the early days, I’m encouraged by WhatTheyThink’s renewed focus on the process. I look forward to supporting the effort on this project in any way that will be helpful.