The Creativity Paradox: December 2021

Tuesday, December 21, 2021

Attaching the Cover to the Book

In this closing article in this series on book assembly, the covers (cases) and book blocks discussed in the previous articles are brought together in the process called casing-in. In this step, glue is applied to the outside of the front and back of the book block. The book block is placed inside the cover and aligned so that the cover overhangs the block evenly at the top, bottom and front. Then the book is placed under pressure until the adhesive sets.

PraLeg Casing-in Machine by Schmedt

While it is possible to do the casing-in step by hand, and many small book and album companies do, most book plants use some type of automated machinery. The semi automated PraLeg by Schmedt is a good machine to discuss because it is easy to see and understand its operation.

First, the book block is placed over the wing that sticks out at the top of machine. The machines lowers the book into glue area and the cover is placed face up on top of the machine. Then the machine raises the book block through rollers that apply the glue and lifts the block into the cover.

PraForm by Schmedt

Once the cover is attached, the assembled book needs to be pressed and the hinge needs to be formed. The picture at the right shows a book ready to be pressed in a Schmedt PraForm.

The video below shows these steps much more clearly than I can describe them.

The Schmedt machines are used in a wide variety of moderate volume book companies. Muller Martini and other companies make bigger, faster and more automated machines, but internally their function is very similar to the PraLeg.

Tuesday, December 14, 2021

The Case for Hard Cover Books

I spend a lot of time reading and most of it is on the screen of my computer, iPad or phone. But when I am strongly interested in the visual content of a book, I insist on a hard cover book, preferable layflat or Smyth bound. It is far easier and more enjoyable to explore photography, art and architecture in a real book.

In the printing industry, the term for the cover of a book is the case and most cases are made in the same way. Cardboard reinforcements, slightly larger than the book block, are cut for the front, back and spine of the book. They are glued to the back of the cover material which is then wrapped around the edges of the cardboard and tucked in at the corners.

The PraDeka XL from Schmedt is a semi-automated case making machine that works well for moderate volume personalized book manufacturing. As you can see in the picture at the right, the cover, with adhesive on the back, is placed face down on the machines vacuum table and the cardboard is place within the alignment guides. Pressing a footswitch pulls the cover into the turning section which wraps the top and bottom edges. After tucking in the corners by hand, the operator turns the book 90 degrees and presses the footswitch again to wrap the left and right edges.

This is easier to demonstrate than to explain and the video below from Schmedt's YouTube channel is very easy to understand.

While Schmedt builds a range of different equipment for bookmaking, higher volume book binding companies use more automated machines supplied by GP2, Kolbus, and Muller Martini.

Monday, December 6, 2021

Taming the Color Beast

Calibration, Characterization, and Enhancement

To the uninitiated, getting consistent, predictable and pleasing color from a printer or a press can feel like taming a wild beast. The interactions of calibrations, characterizations and individual image characteristics provide a wilderness of complexity where it easy to get lost. However, an organized, step-by-step, process can provide a roadmap through the wilderness to the paradise of perfect color reproduction.

Calibration

Calibration is the first step. Calibration is the process of adjusting an individual device to produce the individual colors at the levels intended by the manufacturer. This is done by printing a target consisting of a simple pattern of patches of increasing density. The Creo target shown below is a very common type of target for a CMYK device.

Each patch on the printed calibration target is measured with a densitometer, a device that measures the amount of light reflected from the surface of the paper. The calibration values are fed back into the printer so it can adjust the exposure or ink levels bringing the printer into calibration.

Because calibrations can be impacted by a wide variety of items including variations in ink viscosity, paper absorbency, temperature, and humidity, they should be checked frequently. Photographic printers should be checked several times per day. In a large offset print run, press sheets should be pulled and evaluated several times per hour. On the most sophisticated digital presses, a calibration strip is included on each sheet and each sheet is measured automatically.

Characterization

Characterization is often called profiling and provides the information about the way a device reproduces color including the breadth or gamut of color that is possible from the device. The resulting profile is used by the Color Management Module to provide the most accurate reproduction of color possible from the device. Proper characterization will allow images to be reproduced as consistently as possible across multiple devices and paper substrates.

To create a color profile, an IT8 color target, as shown below, should be printed on a fully calibrated printer. This target consists of 24 grey patches and 256 color patches which have been precisely defined by the American National Standards Institute. Each patch must be read by a spectrophotometer, a device which measures the reflectance of light across a wide spectrum of wavelengths. These values are fed into the software which creates the profile.

IT8 Target by Hugo Rodriguez

Usually, a separate profile is required for each paper type on each output device, but the profiles can be used for as long as the device and substrate continue to be used together.

Image Enhancement

Once a color system is calibrated and characterized, the characteristics of individual images come into play. No camera system that currently exists can capture, and no printing system can reproduce, the full dynamic range of human vision. Image enhancement is required to adjust the colors in the image so the reproduction comes as close as possible to matching the human perception of the original scene. Some enhancements are global meaning they are applied to the image. Others are local, applied only to specific areas of images.

Professional photographers often enhance their images manually using tools in Adobe Lightroom or Photoshop. Higher volume image companies, including consumer photo companies and web retailers need tools which can automatically analyze and enhance images without human intervention.

One of the best tools for automatic image enhancement is Viesus, from Image Solutions. Automatic global enhancements in Viesus include color, brightness, contrast, sharpening, and noise reduction. Local enhancements include local brightness to lighten the foreground of backlit images or areas in deep shadows; sharpening of hair, eyebrows, and foliage; noise reduction on skies and skin; and specific color correction of skin, sky and grass.