Curve adjustments

[gordo]

I don't know. Is a Glass Blower in the manufacturing industry, or the service industry? Is a Clay Potter in the manufacturing industry, or the service industry? These are both crafts where you are actually making something, as is Printing.

I can see how a Pre Press operator or department would see themselves as being in the service industry, but I don't think the same can be said for a Press Operator. I would think that he would consider himself a skilled manufacturer, and some may call themselves Craftsmen as well.

This can get pretty fuzzy, but I think that in the context that Erik was describing, printing falls very short of being a manufacturing process since printing does not have unambiguous specifications, tolerances, and objective criteria for accepting or rejecting the results of the process. It's all very arbitrary, subjective, and relative.
On the other hand, if you are manufacturing a car - all the components that go into that process are clearly and objectively defined. If parts fail to meet specifications they can be rejected. That is not true of printing. There is no craft in supplying materials to a manufacturer. Either the materials meet specification within defined tolerances or they don't.

 

[Deleted member 16349]

This can get pretty fuzzy, but I think that in the context that Erik was describing, printing falls very short of being a manufacturing process since printing does not have unambiguous specifications, tolerances, and objective criteria for accepting or rejecting the results of the process. It's all very arbitrary, subjective, and relative.
On the other hand, if you are manufacturing a car - all the components that go into that process are clearly and objectively defined. If parts fail to meet specifications they can be rejected. That is not true of printing. There is no craft in supplying materials to a manufacturer. Either the materials meet specification within defined tolerances or they don't.

I just read a few days ago a post on a Linkedin group by John Seymour (QuadTech), where he was commenting on the issue of sampling. That was fine but he was saying that in some ISO standards, if the run was 68% within tolerance, then the run was acceptable. I could not believe what was being said but I guess it was true.

Normally in manufacturing if a product is out of tolerance it is waste but not in the printing industry. OK, because it is a service industry it is OK to be outside tolerance. So the customer is supposed to accept product outside tolerances because an ISO standard says it is OK.

Year after year I am always amazed. Instead of fixing processes so one is capable of printing to tight tolerances, which are required to obtain visual matches, the printing industry thinks it is perfectly OK to set wide tolerances and now it seems to ignore the idea of what a tolerance should be and just say close is good enough.

 

[gordo]

I just read a few days ago a post on a Linkedin group by John Seymour (QuadTech), where he was commenting on the issue of sampling. That was fine but he was saying that in some ISO standards, if the run was 68% within tolerance, then the run was acceptable. I could not believe what was being said but I guess it was true.

Normally in manufacturing if a product is out of tolerance it is waste but not in the printing industry. OK, because it is a service industry it is OK to be outside tolerance. So the customer is supposed to accept product outside tolerances because an ISO standard says it is OK.

Year after year I am always amazed. Instead of fixing processes so one is capable of printing to tight tolerances, which are required to obtain visual matches, the printing industry thinks it is perfectly OK to set wide tolerances and now it seems to ignore the idea of what a tolerance should be and just say close is good enough.

Erik, you need to be more tolerant! LOL

 

[Deleted member 16349]

Erik, you need to be more tolerant! LOL

I'm out of tolerance.

 

[gordo]

Yeah sorry about that, I deleted the post as I decided that I was going to try and stay out of it, but depending on where you look, Printing is actually classified as a manufacturing industry, at least in the United States. I have always considered it as such but like so many other things, I guess that maybe it really depends on who you talk to.

No, in the US printing is an industrial business classified as a service industry as per my reference: (Thomson Reuters Business Classification: Industry 52203020 Commercial Printing Services, Industry group 522030 Commercial Services & Supplies, Business sector 5220 Industrial Services). Note the use of "services" rather than "manufacturing"

In practical terms publication printing skews more to what one thinks of as manufacturing and general commercial offset skews more towards what one thinks of as a service industry.
If you go back to the OP's initial posts it's pretty clear that you wouldn't have that kind of conversation about Hon Hai/Foxconn Technology Group and Apple.

 

[fiatlux]

I'm out of tolerance.

With extreme specificity.

 

[gordo]

NAICS 323:

Printing and Related Support Activities Sector (NAICS 323)
Printing is part of the manufacturing sector (NAICS 31 - 32). It is composed of printing, platemaking and bookbinding; printing is by one or more common processes, such as lithography, letterpress, flexography, gravure, and screen printing.

Printing is part of the Manufacturing Industry in more than one reference, including but not limited to the EPA.

Note the use of 'manufacturing', rather than 'services'.

LOL! That just shows how confused this industry is ;-)

 

[rich apollo]

Sorry, I can't let this go:



With all due respect, and although this is commonly stated in the trade, the function of a proof is NOT to predict what will happen on press. The function of a proof is, color-wise, a target for the presswork to align to.

A proofer and a press are mechanically and functionally purposed too differently for a proof to ever be a predictor of what will happen on press. The only time a proof can be a predictor of what will happen on press is when the proofer is the same device that will print the actual final job.

A proof is made to demonstrate how the file will look if printed under a specific set of conditions. If the press does not perform in accordance to those conditions, then it is very unlikely that the product will resemble the proof.

I like your idea of looking for trends in what the press operator considers 'okay' sheets.

 

[gordo]

A proof is made to demonstrate how the file will look if printed under a specific set of conditions. If the press does not perform in accordance to those conditions, then it is very unlikely that the product will resemble the proof.

That is only partly true. As I've said, their are mechanical differences between a proofer and a press that can mean that even if the press is performing in accordance to a specific set of conditions the presswork may not align with the proof on a job to job basis. Put another way, you can print one job and then immediately print a new job with the only change being the image content and one will align to the proof and the second not. That is because how a press prints is affected by the ink usage resulting from the image content of the live image area. AFAIK that is not the case with a proofer. The impact of this mechanical characteristic of a press can be subtle but at other times be significant.

Some examples:

You don't need to screen a spot color on a proofer in order to match the solid color. But, for example, on press, National Geographic has to screen its iconic spot Yellow border to make it the same color all around the image:

On the left, how the Yellow border would print if run at 100% spot. On the right, how the Yellow border appears on press after the top and bottom part of the border have been halftone screened. (Now it aligns with the proof - but if the proof had shown what was in the file then the top and bottom bars would have been lighter i.e. not showing what would print).

On a proofer inline image content does not affect color output - but on a press it does. That is why there is no need to add ink take off bars, angle/cock, or rotate the live image in order mitigate against mechanical ghosting (whether light or dark print ghosting) on a proof. Inline ink usage issues are a characteristic of many, if not most offset presses, despite a lot of engineering being used on press to mitigate the problem (cue Erik). The ghosting effect of inline ink usage may be severe or it may be subtle - depending on the imagery and hence the ink usage.

On a proofer, there is no need for ink take-off bars to solve image blinding (loss of density) due to low total ink coverage. But on a press, you can quickly see a hue shift or loss of color just because the amount of ink of that color used in the live image area is very small.

There are a host of other factors that can result in the presswork not aligning with the proof even if the press is performing in accordance to the specific set of conditions when the proof was developed.

 

[Deleted member 16349]

On the left, how the Yellow border would print if run at 100% spot. On the right, how the Yellow border appears on press after the top and bottom part of the border have been halftone screened. (Now it aligns with the proof - but if the proof had shown what was in the file then the top and bottom bars would have been lighter i.e. not showing what would print).

On a proofer inline image content does not affect color output - but on a press it does. That is why there is no need to add ink take off bars, angle/cock, or rotate the live image in order mitigate against mechanical ghosting (whether light or dark print ghosting) on a proof. Inline ink usage issues are a characteristic of many, if not most offset presses, despite a lot of engineering being used on press to mitigate the problem (cue Erik). The ghosting effect of inline ink usage may be severe or it may be subtle - depending on the imagery and hence the ink usage.

There is more than one issue with the example and the general problems.

In the example of NG on the left, it looks like what I call starvation ghosting seen on an offset press. It is not an inline ghosting problem but it is related to a failure of the press to distribute ink laterally. Your example does not quite look right but since I can not say for sure what the press operator did, I can't be sure. Normally this kind of starvation ghosting only affect the region quite close the the high coverage image and does not affect the print away from that region. Also since cross bars look a bit red where normally it would be just a higher density yellow, I am guessing you made a sample image for the discussion. I remember seeing this example before but did not comment then. I am also guessing that the screen was not a constant value across the bar. Just a guess.

This problem is still not totally engineered out of modern presses but it can be. It is related to basically two different issues. One is the lateral resolution of the ink keys. The idea here is if one had many ink keys that were very narrow, then it would be easier to target the ink feed to just the areas of the image that need it. The second issue is related to oscillation in the press that laterally transports ink. Basically there are three different modes of oscillation which I won't go into here but the one that is most used in offset presses is also what makes the problem of starvation ghosting worse. But oscillation is the only way to overcome this problem and therefore care must be taken in how oscillation is designed into the press. Some presses are better than this than others. The Anicolor press does not need oscillation and in a way one can say that it has an infinite resolution of its ink feed due to the anilox ink feed and the single form roller that inks the plate in register.

So in a failed condition, and there are several, one would not expect the proof to predict what the press will print. That is why it has always been my view that more effort to improve the performance of the printing devices should have been done so that there would not be so many issues (mess) to deal with.

 

[gordo]

There is more than one issue with the example and the general problems.

[snip]Your example does not quite look right but since I can not say for sure what the press operator did, I can't be sure. Normally this kind of starvation ghosting only affect the region quite close the the high coverage image and does not affect the print away from that region. Also since cross bars look a bit red where normally it would be just a higher density yellow, I am guessing you made a sample image for the discussion.

Correct, it's a made up image to show what National Geographic actually does. They wouldn't elaborate to me on the specifics of the screening they use.
My point in the post was to demonstrate that the mechanical difference between presses and proofer can result in mismatching despite the heroics of press operators and color management gurus. A well run shop understands this and applies strategies to try and minimize the impact on that difference and/or forewarn the print buyer of any potential issues.

 

[Alois Senefelder]

Salient Points

Salient Points

Hello gentlemen of the Colour Management Brigade,

The primary function of the reciprocating action of the Vibrator Rollers

is to - disrupt the Ribbing Pattern of the Inking Roller Train



Regards, Alois