We know why average printers struggle with standards and consistency; but why do the highest-quality printers sometimes find the same issues so challenging?
It's easy to understand why mediocre printers have difficulty hitting print standards. They frequently lack the required equipment, skilled personnel or established procedures needed to run consistently. The question becomes more complicated with high-end, quality printers. Why would a printer with a history of delivering outstanding work to discriminating clients have difficulty maintaining standard industry specifications?
Associating printing to standards with lower quality work. The very word "standard" seems to imply something, well, standard, which to many of us means lacking in distinction or run-of-the-mill. Printers who think this way naturally feel that superior printing means going beyond the standard, usually without actually thinking about what this means.
Thinking that printing "custom" means that standards don't apply to them. Some printers feel that they would be happy to print to standards, it's just that so much of the work they do is custom.
Having the wrong skill sets. Given how many press operators value their well developed skills at running the press differently for each job, it shouldn't be surprising that they may have never fully developed the skills to run their presses in a truly consistent manner.
Not having the proper tools. Many printers feel that if they have a measurement device on press then they have done all that needs to be done, even if that device is clearly inadequate to their needs.
Lacking faith in the process. Despite worldwide success applying standards to high quality printing, many still believe that running to standards couldn't possibly work for them.
Lacking effective press-prepress communication. If prepress is out of the loop, they can't contribute to the process…it's like having a NASCAR team with no pit crew.
Believing that press variables are inevitable and uncontrollable. Experience with on-press variation can cause many to believe that variation "just happens" and nothing can be done about it, stopping attempts at consistency before they even start.
Quality printers have a head start in achieving consistency in hitting standards; but refocus and reevaluation of what quality means.
Drop the outdated notion that standards represent a lower level of printing. Understand that even a house standard (a "higher" standard) must be consistent and repeatable if it is to be useful. Custom tweaking for every job runs counter to the goal of quality. Besides, running consistently isn't nearly as easy as it sounds-in fact, it is the new skill of pressmanship, and many veteran press operators find it the biggest technical challenge of all.
Understand that even "custom" work can be quantified and measured. The most luxurious custom homes are built with the same system of blueprints and tape measures as low-priced tract houses. Printing needs to follow the same model.
Recognize where new skills need to be developed. It can be hard for a journeyman press operator to recognize that he may have a weakness in a fundamental press skill, but this is often the case. We tend to be best at doing things we do day after day, and weak in things that we do only rarely. Pressmen who are extremely skillful at making the press run differently for every job can be very surprised to learn that they never fully developed their skills at making the press run the same way time after time.
Identify the missing pieces in your process control toolbox. No modern pressroom can afford the time to rely on only a hand-held device, and a scanning system that tracks only solid densities is not providing the information needed to truly print to standards. Spectral scanning with full reporting of solids, overprints, TVI, gray balance is absolutely necessary to efficient printing.
You gotta believe. Nobody ever followed through on a project they didn't believe in. Until you and all your team members fully subscribe to the concept that printing consistently to industry standards is the best path to pressroom success, it simply won't happen.
Get press-prepress communication happening. Measurement that begins and ends at the end of a press can't create consistency because it leaves half the team in the dark and unable to contribute. Prepress needs to know at all times how press conditions are affecting color so they can take constructive action to improve the process.
Take control over press variables. Death and taxes may be inevitable, but variation on press can be controlled. It begins with measurement and communication. The detective work leading to the discovery of the causes of variation leads to the reduction or control of press-related variation.
Standards and tight process controls are not incompatible with ultra-premium quality-they are prerequisites for it.
It's understood that print buyers are concerned with quality and price, and printers are concerned with efficiency and profitability; but a recent presentation by Martine Padilla made me realize that these goals are not only not in conflict, but are in fact complimentary parts of a common goal.
Martine's presentation, given at this year's DSCOOP Conference, is nearly an hour long, and after listening several time and taking notes, I'm still turning the message over in my mind, so all I can offer here is the very briefest encapsulation; but please check it our or read Martine's synopsis, because I think it addresses issues that are beginning to resonate in our industry on multiple levels.
Very quickly, Martine's focus is on sustainability in print, and the presentation outlines how this goal unites the interests of printers and print buyers in unexpected ways.
Print buyers have an interest in getting accurate printing at a good price.
Printers have an interest in reducing waste in order to turn better profits.
These goals seem at first to be in conflict, or at least unrelated.
Brand owners have and interest in both #1 and #2. They want to purchase quality printing at a good price, and they also want to know that the print was produced responsibly and sustainably.
The interests of the brand owners in having quality printing produced responsibly and sustainably unify the interests of both buyers and printers in achievement of a common goal.
Wow. Does everybody else see why this is an absolutely perception-bending shift? By printing sustainably, printers can offer a valuable service to their most important clients while saving money on production and becoming more profitable themselves.
Part of what makes this fit together is an expanded definition of sustainability that includes familiar factors like FSC, but then goes far beyond them to include a wholistic array of factors including substrates, ink and chemicals, waste reduction, carbon footprint reduction, best business practices, continuous improvement, and energy efficiency, not to mention ethical, societal and fiscal factors.
One focal point of all of this is the Sustainable Green Printing Partnership, and their website has extensive information on the subject, but me say this another way, because I'm really finding the whole concept to be too big to easily fit into a sentence: As corporations are learning that environmental responsibility is an important component of their brand message, printers are finding that one of the most valuable services that they can provide to their best corporate clients is their own efficiency and profitability, created as a natural consequence of doing what is best for themselves in the first place.
Clearly it is going to take more than one post to cover all that is implied by the developing print sustainability movement; it is the broad scope of the initiative that makes it so exciting. So I will be following up on the theme in future articles, looking at individual areas where the interests of printers, buyers and brand owners come together for everyone's benefit. There is something solid here, and I am determined to learn more about it.
An awful lot of ink has been spilled wondering what would be the next big thing in print. I think this may be it.
I try to keep all my posts informative and product promotion-free. If you are interested in the subject, please check out my other posts, and be sure to browse my website for more information on accurate color and effective prep-press-buyer collaboration.
The ISO 3664 lighting standard was meant to give a more realistic simulation of real-world viewing conditions by increasing the amount of activity in UV spectral regions. Mission accomplished; but it has also revealed long-standing issues in proof-press matching that had previously been hidden.
Color engineers don't particularly like UV because it can create serious complications in measurements: this is one reason why calibration and linearization systems for proofing devices so often make use of instruments that filter out UV light before it can reach the surface of the proofing substrate. Using light stripped of its UV component eliminates the "black light" effect that can cause papers with optical brighteners to "glow in the dark" and take on an additional bluish brightness.
For similar reasons, GRACoL has long specified paper with essentially neutral whitepoint and no optical brighteners (chemical agents that absorb light in the UV range and reemit light in the visible range).
As GRACoL and standards-based printing took hold in the United States, manufacturers of proofing papers took considerable pains to supply the market with the proofing papers that matched white point aims specified by GRACoL…..and for a while everybody was fairly happy. But soon, perceptive viewers began to notice that the wonderfully GRACoL-compliant papers that manufacturers had created at considerable expense simply didn't match the ultra-bright, OB-using, blue white papers that had become so popular with print customers.
Paper companies had discovered the preference for a bright blue look, and the preference for blue is nothing new. Mrs Stewart's bluing has helped keep laundered fabrics looking white since 1883. Her original product used Prussian Blue dye to give white clothes their fresh bluish white look. Modern printing papers use UV activated optical brighteners to give a bluish shift and at the same time boost brightness.
ISO 3664, which specified increased levels UV activity in D50 graphics arts lighting, gave a standard that was closer to "real" daylight, but at the same time exposed even more strongly some of the problems being caused by the mismatch between OBA-free proofing papers and OBA-laden printing paper.
At first blush, it seemed as if switching back to proofing papers containing OBAs would be an easy way of matching proof appearance to final print paper output, but unfortunately, this is not the case. As the illustration shows, different OBAs may fluoresce at different hues, from deep purple to a pastel bluish white, and there is no standard for for appearance of OBAs. What this means in practical terms is that there is currently no objectively verifiable way for accurate matching of OBA containing proof papers to OBA containing printing papers.
ISO 3664 has given us a lighting standard closer than ever to actual daylight, but at the same time it has revealed more strongly than ever before existing issues with proof press matching. Until this dilemma is resolved, we may all be forced to reevaluate the best methods for matching proof and press sheet.
I try to keep all my posts informative and product promotion-free. If you are interested in the subject, please check out my other posts and be sure to browse my website for more information on accurate color and effective prep-press collaboration.
For prepress managers, "One good sheet to the numbers" is often all they need to help press operators get better results via corrective plate curves. So why is it so hard to get one? I take a look at that question in this post.
Press operators don't ask for help a lot. These are usually guys with a lot of techniques to getting a visual match. They are optimists, too. They generally believe that the can "get there" in terms of color matching, no matter how discouraging it looks at first.
So it takes a fairly tough color problem for a press operator to take sheet in hand, call in the prepress guy and say, "Can you help me out with a curve for this?" When the request is finally made, it is too often preceded by a long makeready attempt, tall piles of waste paper, and a series of head-scratching huddles in the viewing booth.
It usually goes back and forth for a while, with the prepress guy taking his best guess at a corrective curve, the press operator pulling a few more tricks out of his hat, and together, they finally get an acceptable match. And so it goes until next time.
Why is it so difficult for prep to get a sheet to the numbers, and why do press departments so often have to struggle with inadequate plate curves?
It seems clumsy to take time out from a makeready session to set aside a sheet to the numbers that the prepress may or may not eventually do something with.
Press and prep are in different rooms, and this makes communication difficult.
Even if the press operator runs a sheet to density and sets it aside, it's usually hard to find it when you need it.
Pressmen have so much negative experience "running to the numbers" that they generally prefer to just go for a visual match.
Prepress guys usually don't have time to do dot-gain measurements of press sheets to figure out if curve adjustments are needed.
Forward-thinking operations have embraced standards-based printing and recognize the need for increased communication of press measurements. Most quality printers strive to establish communications between press and prepress via fingerprint runs, regular meetings or other techniques, but the needed transfer of information from press to prep still tends to lag.
The missing link in press/prep communications has been a way to get information delivered directly from the press console to the prepress department, with no additional steps and in real time.
The problem has been that even with proper measuring equipment in use, measurement information (density, dot gain, gray balance, spots) tends to get stuck at the end of the press, and moving it out into the prepress department has proved to be a serious challenge.
These communication capabilities do now exist, and are available for printers of all sizes for less than the cost of a new hand-held densitometer." Every prepress manager and pressroom supervisor can now have instant access to vital data from every measured sheet.
It seems only yesterday that debate raged, or at least quietly burbled, regarding plate curves and color bars. "Should color bars be curved, or should they be linear?" was the question that inquiring minds wanted to know. Happily, that question has been resolved for most, if not all printers. The absolute condition of the press, as represented by linear color bars, has been deemed to be far less important that the actual net color results as measured by color bars that have received the same curve treatment as the actual images, and the large majority of printers give their color bars exactly the same treatment as the rest of the job. After all, we want the color bars to be a true reflection of the actual appearance of the job.
But what about ink optimization? (AKA ink savings, GCR, or various sorts of secret sauce). Should color bars get the same treatment as the image, as they do with curves, or should they shielded from optizimation treatments? Based on informal conversations, it seems like quite a few users feel that indeed, ink optimization should, like curves, be applied globally, to image and color bars equally; but in fact, the situation is completely different, and ink optimization is not only inappropriate for application to color bars, but is absolutely detrimental to their utility and may even represent a sort of false representation of results, particularly in a G7 enviornment.
To illustrate exactly why optimization is so detrimental to the utility of color bars, I'd like to start with a basic color bar of the kind that is frequently configured to fit onto the end-flap of package products (and thus cannot easily escape the effects of optimization, since it is integrated into the image).
This little collection of just ten patches is just enough to judge compliance to G7 specifications with great accuracy, and can either be spread across the press sheet in the traditional manner, or as stated above, hidden into the end flap of the product. It includes solids of CMY and K as well as 25 50 and 75 percent patches of K and CMY grays, A perfect, minimal and effective QC tool. But will it withstand ink optimization?
To see, I have integrated it into some images we all know very well.
There they are, our three favorite girls, the SCID musicians, with a G7 color bar in the corner to assure that all is fine and in perfect gray balance (subject to the limits of web viewing).
In order to simulate a perfect storm, I have created a rather serious color imbalance, the kind that the G7 specification is designed to monitor and control. In this case, while solid ink values have remained perfectly constant, a shift has happenned in the Cyan and Magenta TVI, causing a shift in gray balance that is equally visible both in image and color bars.
The image here is seriously out of balance, but the color bars have done their job. The 25 50 75 CMY gray bars show the same shift we see in the image, allowing process control specialists to spot the unacceptable color variation and reject the job.
Now let's take a look at the same imagebut this time including aggressing GCR/ink optimization.
This image looks like at first like a victory for ink optimization. This image of the musicians, which were subjected to the same imbalances as the unoptimized image, looks better than the unoptimized image. There is still shifting of the clothes, the flesh tones, the background, but the shifting has at least been reduced. But what about the color bars? Oh my! They are absolutely perfect! Any objective measurement of the color bars would show that we have a 100% perfect job, with complete compliance to G7 in every way, But there is one small problem. The actual image, while better than the unoptimized image is still visually unacceptable, yet based on the color bars, it would have passed QC inspection. How did this happen?
If we peel away the black to look at CMY and K separately, we see that black tints are reproduced with tints of black, amd CMY tints are reproduced with tints of CMY, just as expected.
Performing the same operation on the optimized file, we see that the black tints are reproduced using tints of black, and CMY tints are reproduced with….tints of black! They have completely lost their predictive power as QC devices, and no amount of TVI shifting will cause the slightest shift in gray balance.
With optimization, the image fares less well than the color bars. While GCR does an excellent job of protecting neutrals from shifting, this effect diminishes as we move away from the neutral axis to more saturated colors. Since most images contain many colors, they will invariably tend to fare worse than color bars designed with perfect CMY neutrals.
Does this mean we shouldn't use ink optimization? Not at all. Optimization/GCR of images with non-optimized color bars is an excellent way to save ink, shorten makeready and increase stability on a wide range of images. But optimization is entirely inappropriate for color bars. Optimized G7 color bars can produce "false negatives" indicating a G7 compliant job even when TVI values and corresponding image appearance are seriously shifted. Be sure that across-the-sheet plate colorbars are excluded from the optimization portion of the workflow. And if colorbars are integrated into the image, such as patches hidden into packaging end flaps, be sure that any image optimization is done off-line, prior to plating, so that color patches can be excluded.
A big part of what I do as a color consultant involves helping printers to achieve better quality and efficiency through process control, color management and enhanced communication. Not all printers understand the need at first, but most do finally see how their operation can achieve gains that make the small investment worthwhile.
One of the toughest challenges is answering the manager who says, "We've got a guy who does that". It sounds likely at first. Most shops do have somebody (usually in the prep department) with an interest in color management and lots of ideas for improving the operation. Some of the very best color consultants I know were once guys like that, carrying out a full load of retouching, assembly, troubleshooting and platemaking duties in the course of a day, and doing their best to handle color management duties in their free time between rush jobs.
But is it really accurate to say, regarding color communication issues, that "We've got a guy who does that?" I'd say that it's very unlikely, in part because even if you already do have a guy who could do that, he probably isn't being allowed to.
Really expert color guys aren't that easy to find. There just aren't that many real color experts hanging about.
Expertise takes practice. Even the best in-house color experts are usually too busy with production work to focus on the details of color management and process control, and don't always get a chance to polish their CM skills. We all know that this is true: when a rush job needs to get out the door, everything else stops, and these days, with personnel cutbacks at every corner, nearly every job is a rush job, with barely enough hands on deck to get it out. Color management is a luxury when you are scrambling to get the work done.
Color production is collaborative. There is really no such thing as individual color management, because it involves all sections and all departments. Every job travels through multiple departments, which means that a color expert, even a very skilled on, working in a single department, can improve only a portion of the process.
Establishing good color management and process control requires that procedures be set up and followed, and these procedures usually require a new kind of relationship between press and prep departments, a relationship where the press department is required to be responsible to the prep department in hitting specifications and reporting to the prep department. One problem: Peers don't tell peers what to do. The prep manager (who is usually the in-house color guy) has no authority over the press manager, and so can't really demand anything at all from him. Result: the required new procedures are never put into place.
Authority flows downhill. This is an extension of point 4. The in-house color guy rarely has the authority to make significant changes, and the plant manager or COO rarely has the expertise or time to implement these changes himself. Result: as above, very limited success.
Even when there is a very talented color guy in-house (and it happens), he will rarely have the time or authority to make the needed changes needed for real improvement in the overall process. The role of the outside color consultant is not only to provide a level of expertise and experience not often available in-house, but also to bring in the independence and perspective that can only come from the outside. The outside color expert is often the push that is needed to allow the inside color expert to finally be allowed to do his job.
I worked for many years with print buyers from the entertainment industry-those hip and trendy people who bridge the space between the glamor world of Hollywood and the grubby trenches of the commercial pressroom. Entertainment media buyers were always on press OK's, calling out color changes right through the run, trying to get the perfect "look" that captured the feeling of the movie and somehow, mysteriously, transmitted that feeling throughout the print campaign.
Standards were absent, not talked about and not even thought about. Pressmen did whatever it took to Get That Look, no matter how long it took. The goal of the movie ad campaign was to transmit some elusive emotional connection that, in the eyes of the print coordinator, defied measurement.
How different from the print buyers that I work with in packaging! Demanding, matter-of-fact, and with no illusions of stardom, packaging buyers seem to have come from another planet, so I wondered, where DO packaging print buyers come from?
Well, in not a few cases, they come from manufacturing. Some of the best packaging print buyers I know started off doing QC for the products that went into the package in the first place. When you are QCing a product, you look for conformance to specifications. It is different for every product, of course, but in almost all cases, the evaluation is done objectively by measurement.
Is this food portion the correct weight? Does this component have the correct electrical properties? Does this fabric have the specified tear resistance? In every case the question is answered the same way: Measure it and find out.
For manufacturers who make a product to specifications, measurement is a given, and when they specify a package for their product to go into, it makes perfect sense to use the same approach.
Packaging print buyers know that emotion and feeling are unreliable guides when it comes to maintaing a brand color throughout a print process that may take place at multiple locations over an extended period of time. For these buyers, using the same tried and true methods of measuring for quality that they used for doing QC on the product itself comes naturally.
Printers who understand their buyers and use measurement to produce a consistent print product are on the same wavelength as their customers and build an easy and harmonious relationship. Fortunately there is a way for both buyers and printers to maintain this relationship smoothly on both sides. PressSIGN Buyer enables buyers to specify and verify the accuracy of brand color in their own offices, and PressSIGN Pro enables printers to measure and track their printing accuracy while the job is being printed, and provide detailed reports to their buyers for no surprises later on.
The colors most important to your printing client many be any of the 16.8 million different colors that can be defined within the printing process: How can you possibly determine if your printer has done an acceptably accurate job of matching these target colors when they represent the tiniest needle in a vast color haystack?
It's a puzzling problem that has troubled buyers for as long as they have been specifying print. We can't possibly measure every single color, and the standard alternative of making a gut decision based on eyeball judgment is unreliable and prone to error. How can we make an accurate and objective evaluation of color quality without drowning in a sea of data?
"Thin Slicing", a term coined in 1992 by Nalini Ambady and Robert Rosenthat suggests an effective way out of this quandary. Thin Slicing refers to the ability to make rapid yet accurate judgment based on very limited data. Is there a way that we can "Thin Slice" print buying?
Really, perhaps without quite knowing it, print buyers use thin slicing every time they evaluate a color print job. The buyer may not know the countless factors that can affect the color match of a printed job, but they are still able to make a quick judgment based on a narrow range of patterns that affect overall performance. That's thin slicing, and it works.
But there are limitations to the intuitive, eyeball-based evaluation process. It is inevitably subjective and liable to outside influences of all sorts. It doesn't lend itself to documentation, and unconscious bias is hard to avoid. So can media procurement secialists find an objective and quick way to "Thin Slice" their print buy to assure the best possible quality/value ratio?
There is a solution: thinslicing can be automated. Modern press measurement systems make it possible to collect, display and analyze that thin slice of the twenty or so absolutely essential metrics that represent accurately the overall quality of the reproduction. The best of these systems deliver this information in a way that is immediate, sharable, and vivid.
What are the essential elements of color measurement that make print thinslicing both effective and understandable?
Primary colors: Traditionally thought of as "density", today we measure the entire color data of Cyan, Magenta Yellow and Black solids. Despite its many years of use, density alone is a weak predictor of overall color accuracy. Colorimetric measurement of primary hues provides a better guide.
Overprints: The three possible 2 color compinations of the primary colors produce the overprint colors of Red, Green and Blue. These colors are well defined by ISO standards and are strong indicators of overall color accuracy.
TVI, or Dot Gain: TVI measures the quality of the 90% of the image that is not composed of solids. By measuring that great middle area of color reproduction, TVI or Dot Gain, provides and even stronger indicator of overall color accuracy than prinmaries or overprints.
Gray Balance: This is affected by all the other components of primaries, overprints and TVI. Gray is also the color most easily discerned by the human eye. Put it all together and gray balance is the single strongest indicator of color accuracy.
Consistency: A sheet that is too dark on one side and too light on the other side may be great on the average, but is not acceptable as quality printing. Consistency across the sheet and throughout the run is an indispensible element in quality printing.
In choosing a color verification system, look for one that tracks all 5 factors, and delivers them instantly to all parties.
By now, if you have been paying attention, you have probably come to realize that an offset printing press cannot be controlled through density alone. The success of the G7 process has demonstrated that gray balance is the single greatest determiner of color appearance; and while a number of different factors contribute to gray balance, it is primarily determined by dot gain, or TVI.


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Q: Does the finite intersection property apply here? Suppose $X$ is a topological space. Now let $A_1 \supset A_2 \supset \cdots$ be a sequence of closed subsets of $X$. Suppose $a_i \in A_i$ $\forall i$ and $a_i \rightarrow b$. Prove that $b \in \bigcap A_i$. Now I'm not so sure if I should do this, but do I need to use the finite intersection property somehow to get to the conclusion? If so, how exactly? I would appreciate all the help I can get, thank you.

A: This is less by finite intersection properties, and more by the definition of closed sets and convergence.
Recall that $a_i\to b$ if for every open set $U$ such that $b\in U$ there is some $i_0$ such that for all $i>i_0$ we have $a_i\in U$. This means that by removing a [proper] initial segment of the sequence we do not affect the convergence of it.
Now recall that $b\in\operatorname{cl}(A)$ if and only if every open set $U$ which contains $b$ has a nonempty intersection with $A$. If $A$ is already closed then $\operatorname{cl}(A)=A$.
What you need to write, if so, is that whenever $U$ is an open set such that $b\in U$ then $B\cap A_i\neq\varnothing$ for all $i$, and therefore $b\in A_i$ for all $i$, and so $b\in\bigcap A_i$.

A: Fix $n\in\Bbb N$; then $a_k\in A_n$ for every $k\ge n$, $\langle a_k:k\ge n\rangle\to b$, and $A_n$ is closed, so $b\in A_n$. But $n\in\Bbb N$ was arbitrary, so $b\in A_n$ for every $n\in\Bbb N$, and the result is immediate.

redpajama_set_name: RedPajamaStackExchange


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Q: How to find the column value with the biggest storage size in the DB? Is there any way to find out which column value has the largest storage out of all tables in PostgreSQL DB?
I'm looking for currently used storage, information_schema.column only shows the length of the datatype. Looking for something like max(pg_column_size()).