Hypothesis: Pressing causes long-term damage to comics 2 2

[tb]

Thanks for starting this thread. This is the most productive one I've ever seen in terms of answering this question.

 

For several years, I've had an idea to an experiment that I think might decide whether pressing is harmful. I've tried to post it a couple of times but it always gets lost with no replies.

 

Just for context, I was enroled in the Ph.D. program in Computer Science at MIT and also did research related to Materials Science at Stanford. I did not study paper per se, but I read hundreds of research papers on the decay of other materials and also came across some on paper. My results were published as part of an article in Scientific American.

 

One article that I remember in particular was a Swedish study on the strength of paper. They used a technique that appeared to be fairly common. First, the paper was baked in an oven for a long time at a relatively low temperature. This simulated the aging process. Then each sheet of paper was folded and bent back and forth until it broke. The number of times it was bent was counted.

 

Now, suppose you took two 64 page comic books, each made up of 16 sheets of paper. After removing the staples, the two books could be mixed into two new books where book 1 would contain sheet 1, 3, 5, ... from book 1 and sheet 2, 4, 6, ... from book 2. Next, one book could be pressed and the other left as is. Both books could then be baked to simulate aging after the pressing. Finally, the bending experiment would be performed and the number of bends for each sheet would be noted. If the pressing damaged book 1, I would expect the counts to be lower than for book 2, otherwise not.

 

Just an idea. I've thought about doing this myself, but since noone else seemed to care I didn't want to spend time on it. In any case, I very much welcome the discussion on how this question can be answered scientifically.

 

[bronze_rules]

If I was to approach it from a scientific point of view, I would tend to think spectroscopy would be a good starting point. It seems fairly well established as a tool to determine the characterization (including degradation) of paper.

 

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THN-4VGF3T5-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=922f4899ab672f98ae6e1806deecbcc9

 

http://aic.stanford.edu/sg/bpg/annual/v10/bp10-06.html

 

Considering how much money CGC has for R&D, they should easily be able to afford such a tool or outsource to a consulting firm to run some statistical studies on this (if they wanted to). It would be a simple matter to grab a few hundred or even thousands of samples of non-pressed comics, and pressed comics (with equivalent pressing techniques, that could be further subclassified by type) then run some t-tests on some of the characteristics of the material. It's not exactly rocket science, the field is pretty far along. That's why earlier on I mentioned any established forensics lab (which has much more complex issues to tackle on their plate) as a good field to consult on the issue.

 

If they could confirm the null hypothesis that pressing has no (adverse) effects on comics vs. non-pressed comics, the issue would be dead right there and they could proclaim some study to verify the conclusion. On the other hand, if there was some evidence of pressing being an issue, they could easily afford to buy a spectroscopy instrument for in house use and identification.

 

Once again, not an impossible task by any means. Motivation and incentive seem to be the only hurdles.

 

Thanks for starting this thread. This is the most productive one I've ever seen in terms of answering this question.

 

For several years, I've had an idea to an experiment that I think might decide whether pressing is harmful. I've tried to post it a couple of times but it always gets lost with no replies.

 

Just for context, I was enroled in the Ph.D. program in Computer Science at MIT and also did research related to Materials Science at Stanford. I did not study paper per se, but I read hundreds of research papers on the decay of other materials and also came across some on paper. My results were published as part of an article in Scientific American.

 

One article that I remember in particular was a Swedish study on the strength of paper. They used a technique that appeared to be fairly common. First, the paper was baked in an oven for a long time at a relatively low temperature. This simulated the aging process. Then each sheet of paper was folded and bent back and forth until it broke. The number of times it was bent was counted.

 

Now, suppose you took two 64 page comic books, each made up of 16 sheets of paper. After removing the staples, the two books could be mixed into two new books where book 1 would contain sheet 1, 3, 5, ... from book 1 and sheet 2, 4, 6, ... from book 2. Next, one book could be pressed and the other left as is. Both books could then be baked to simulate aging after the pressing. Finally, the bending experiment would be performed and the number of bends for each sheet would be noted. If the pressing damaged book 1, I would expect the counts to be lower than for book 2, otherwise not.

 

Just an idea. I've thought about doing this myself, but since noone else seemed to care I didn't want to spend time on it. In any case, I very much welcome the discussion on how this question can be answered scientifically.

[namisgr]

If I was to approach it from a scientific point of view, I would tend to think spectroscopy would be a good starting point. It seems fairly well established as a tool to determine the characterization (including degradation) of paper.

 

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THN-4VGF3T5-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=922f4899ab672f98ae6e1806deecbcc9

 

http://aic.stanford.edu/sg/bpg/annual/v10/bp10-06.html

 

Considering how much money CGC has for R&D, they should easily be able to afford such a tool or outsource to a consulting firm to run some statistical studies on this (if they wanted to).

 

Unfortunately, CGC has no money at all for R&D. Supposedly, they can barely turn a profit flipping books in and out the door as fast as humanly possible. The only alterations in the product over the years have been with the inner well design, and these likely were done on a trial-and-error basis. Today's spectrometers are powerful devices for analyzing the chemical composition (and decomposition) of materials, but they typically run five figure dollars to purchase, and require skilled, well-trained technicians to operate.

 

While we're discussing the long-term consequences of comic book pressing, it would be worthwhile to consider also long-term effects of encapsulation in CGC slabs. The books lack the acid buffering that comes from a good, calcium carbonate-infused backing board, and they also are supported by plastic that sometimes doesn't lay completely flat. Heck, I'd be far more concerned about the potential negative impact on the hobby of long term storage of otherwise high grade comics in CGC slabs (of which there are a lot) than I would the effects of localized pressing (of which there are relatively few). In particular, I'm concerned that encapsulated books might run serious risks over the long term for both acid-driven paper deterioration, and inner well-driven warping.

[John A III]

One of the best informative threads I've read on these boards.

[stagedoorjohnny]

 

Assuming (as I do) that glossy comic book paper reacts the same way as other kinds of paper.........

 

A basic chemistry lecture would do you wonders and the lab so much more............

 

yeah, you the man!

 

Although I do not agree with ImageMask's delivery, he is right. This assumption is 100% inaccurate.

 

All the information being delivered here sounds great to the ears. But the only thing that is relevant is information and testing on newsprint, (uncoated groundwood) which is the insides of the comic book and if you want to include the cover, coated groundwood. Tests on anything else and any other paper grades mean little or nothing to this discussion.

[Ze-man]

 

Assuming (as I do) that glossy comic book paper reacts the same way as other kinds of paper.........

 

A basic chemistry lecture would do you wonders and the lab so much more............

 

yeah, you the man!

 

Although I do not agree with ImageMask's delivery, he is right. This assumption is 100% inaccurate.

 

All the information being delivered here sounds great to the ears. But the only thing that is relevant is information and testing on newsprint, (uncoated groundwood) which is the insides of the comic book and if you want to include the cover, coated groundwood. Tests on anything else and any other paper grades mean little or nothing to this discussion.

 

Imagemask grabbed part of Scotts quote out of context to question I assume Scotts technical background. His post had had nothing to do with the composition of paper, PH levels, whatever.

 

Scott was answering a question about flaws reverting after they had been pressed. '

Assuming (as I do) that glossy comic book paper reacts the same way as other kinds of paper, there is no real evidence that I know of that a properly pressed artifact will revert to its pre-pressing state decades after the fact. There are thousands of artifacts that have been pressed (including the Declaration of Independence) that have not reverted despite the passage of decades.

 

 

 

 

 

And I think you are wrong Stagedoor, in the sense of I think the covers should be included in this discussion because they are the item that is bearing the brunt of the heat, if heat was even used. The interiors will warm up but they are not the pages being pressed. You cannot really heat press interior flaws with a flat press.

 

 

I think all of this wondering, testing and concern comes down to if a heat pressed book will age faster then one that was not pressed. And that all depends on the condition of the paper to start with and how hot and long it was pressed. Which is never a constant. imho, a mildly heat pressed book is not what I would worry about compared to somebody that is cranking up the heat and mashing the crud out of their comic because they do not know what they are doing.

 

Year ago I heat pressed several sets of books in similar condition(same eras, BA/SA, same titles, same collection to the best of my knowledge) For all intentional purposes they all looked and felt similar. Pressed them at various heat temps/increments of time. Then baked the pages from both unpressed and pressed books and preformed typical fold tests on each set.

 

I noticed no difference in any of the pressed vs unpressed till I got the book I left in the press at way too hot a temp, for way to long. Basically the one I baked before baking it.

 

What did I take from this? That if done properly heat pressing did not dramatically alter the paper unless it was pressed at dangerously high heat levels. I did these experiments because I was honestly curious about what effect it had on the paper, and is in part why I altered my stance on pressing years ago. I never posted my experiments or results because it would have just been written off as self serving.

 

 

[FFB]

Thanks for starting this thread. This is the most productive one I've ever seen in terms of answering this question.

 

For several years, I've had an idea to an experiment that I think might decide whether pressing is harmful. I've tried to post it a couple of times but it always gets lost with no replies.

 

Just for context, I was enroled in the Ph.D. program in Computer Science at MIT and also did research related to Materials Science at Stanford. I did not study paper per se, but I read hundreds of research papers on the decay of other materials and also came across some on paper. My results were published as part of an article in Scientific American.

 

One article that I remember in particular was a Swedish study on the strength of paper. They used a technique that appeared to be fairly common. First, the paper was baked in an oven for a long time at a relatively low temperature. This simulated the aging process. Then each sheet of paper was folded and bent back and forth until it broke. The number of times it was bent was counted.

 

Now, suppose you took two 64 page comic books, each made up of 16 sheets of paper. After removing the staples, the two books could be mixed into two new books where book 1 would contain sheet 1, 3, 5, ... from book 1 and sheet 2, 4, 6, ... from book 2. Next, one book could be pressed and the other left as is. Both books could then be baked to simulate aging after the pressing. Finally, the bending experiment would be performed and the number of bends for each sheet would be noted. If the pressing damaged book 1, I would expect the counts to be lower than for book 2, otherwise not.

 

Just an idea. I've thought about doing this myself, but since noone else seemed to care I didn't want to spend time on it. In any case, I very much welcome the discussion on how this question can be answered scientifically.

 

tb,

 

The MIT folds strength test that you're describing is one test for the strength of paper. There are other tests, such as the burst test and tear test. I think it would be interesting to try all of the paper strength test methods on pressed samples and unpressed samples. One thing about your suggestion that I think could be improved for the sake of more accurate results would be to have multiple books from multiple publishers over multiple ages so that variances in paper quality are taken into account. I also don't think that swapping out wraps between books would work because you can't guarantee that both of the books would have the same initial paper strength. I think it would be better to just cut the exemplar books in half (sliced across the middle of the cover from left to right so that you wind up with a top half and bottom half for each sample) and press the top halves, leaving the bottom halves as the "controls." You would then be able to artificially age the top halves and bottom halves after pressing the top halves and then run the different paper strength tests to compare the results.

 

The tests could be run at the Forest Products lab at UC Berkeley, if you know someone with a contact at UCB. There may be other things we haven't thought of, but this would certainly be a good start in terms of getting some actual data on the issue of how much of an effect a dry mount press job has on a comic book. It would not answer the question as to all types of pressing, but I think it's the dry mount press jobs that most people are curious about.

[whisp]

How are these tests performed for :

 

1) MIT fold strength test

 

2) burst test

 

3) tear test

 

??

[FFB]

 

Assuming (as I do) that glossy comic book paper reacts the same way as other kinds of paper.........

 

A basic chemistry lecture would do you wonders and the lab so much more............

 

yeah, you the man!

 

Although I do not agree with ImageMask's delivery, he is right. This assumption is 100% inaccurate.

 

All the information being delivered here sounds great to the ears. But the only thing that is relevant is information and testing on newsprint, (uncoated groundwood) which is the insides of the comic book and if you want to include the cover, coated groundwood. Tests on anything else and any other paper grades mean little or nothing to this discussion.

 

Try reading the snippet in its original context and see if you still think it is 100% inaccurate.

 

I never said that glossy cover stock reacts the same as any other kind of paper with respect to aging - only with respect to the possibility of reversion after pressing. If you have some evidence to the contrary, please post it.

 

Also, no one is equating Springhill Offset testing results with newsprint on a 1:1 basis. We're just discussing the results from the LOC's article. To say that these results are completely irrelevant to how groundwood paper ages is not accurate either. The lignin in the groundwood pulp will obviously cause the paper to age more rapidly and create additional aging byproducts than lignin-free paper like the Springhill Offset, but that does not mean we can't discuss the Springhill Offset results at all.

[stagedoorjohnny]

And I think you are wrong Stagedoor, in the sense of I think the covers should be included in this discussion because they are the item that is bearing the brunt of the heat, if heat was even used. The interiors will warm up but they are not the pages being pressed. You cannot really heat press interior flaws with a flat press.

 

 

Absolutely. And also how the uncoated groundwood reacts with the cover, not just seperately.

[stagedoorjohnny]

Also, no one is equating Springhill Offset testing results with newsprint on a 1:1 basis. We're just discussing the results from the LOC's article. To say that these results are completely irrelevant to how groundwood paper ages is not accurate either. The lignin in the groundwood pulp will obviously cause the paper to age more rapidly and create additional aging byproducts than lignin-free paper like the Springhill Offset, but that does not mean we can't discuss the Springhill Offset results at all.

 

 

I see where you are coming from. But a groundwood sheet is so much different from a freesheet, I don't think you could equate the results with anything. They are completely different types of paper by nature and manufacturing process.

[FFB]

Also, no one is equating Springhill Offset testing results with newsprint on a 1:1 basis. We're just discussing the results from the LOC's article. To say that these results are completely irrelevant to how groundwood paper ages is not accurate either. The lignin in the groundwood pulp will obviously cause the paper to age more rapidly and create additional aging byproducts than lignin-free paper like the Springhill Offset, but that does not mean we can't discuss the Springhill Offset results at all.

 

 

I see where you are coming from. But a groundwood sheet is so much different from a freesheet, I don't think you could equate the results with anything. They are completely different types of paper by nature and manufacturing process.

 

What are you basing that statement on? There is quite a bit of scientific evidence that suggests that it is acidity, and not necessarily the lignin content of the paper, that determines paper strength and permanence upon aging. Springhill Offset is alum-rosin sized, which means it is inherently acidic. I will grant you that high lignin content paper tends to react more with atmospheric pollutants than lignin free paper, but that's why it's not appropriate to compare the Springhill Offset results 1:1 with high lignin content groundwood. But that does not mean you should make the logical leap that we can learn nothing from the Springhill Offset results and simply disregard them as though high lignin content paper will react the opposite way upon aging. It simply means that they will age at different rates, with the high lignin content paper aging faster.

[bronze_rules]

I can't imagine them having razor thin profit margins, considering the percentage and frequency of high end books they process. Since they aren't public, we can't see the actual profit margins, but c'mon how much overhead can a small outfit like that have?

I would suspect they are making HUGE profit margins off the high end books, more than enough to compensate for time spent on some lower tier items.

Heck they could donate a pittance to some local university to get grad students to do a study.

 

There was (I don't know if it still runs) a program that had two guys run all kinds of experiments to verify myths, yeah it was called mythbusters. They usually liked to blow things up or tear things apart, but on one episode they tried to see if they could rebuild a phonograph needle from a piece of glass or something. Someone should contact them to do a segment on effects of pressing and sturdiness of plastic encapsulation (explosives part).

 

 

 

If I was to approach it from a scientific point of view, I would tend to think spectroscopy would be a good starting point. It seems fairly well established as a tool to determine the characterization (including degradation) of paper.

 

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THN-4VGF3T5-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=922f4899ab672f98ae6e1806deecbcc9

 

http://aic.stanford.edu/sg/bpg/annual/v10/bp10-06.html

 

Considering how much money CGC has for R&D, they should easily be able to afford such a tool or outsource to a consulting firm to run some statistical studies on this (if they wanted to).

 

Unfortunately, CGC has no money at all for R&D. Supposedly, they can barely turn a profit flipping books in and out the door as fast as humanly possible. The only alterations in the product over the years have been with the inner well design, and these likely were done on a trial-and-error basis. Today's spectrometers are powerful devices for analyzing the chemical composition (and decomposition) of materials, but they typically run five figure dollars to purchase, and require skilled, well-trained technicians to operate.

 

While we're discussing the long-term consequences of comic book pressing, it would be worthwhile to consider also long-term effects of encapsulation in CGC slabs. The books lack the acid buffering that comes from a good, calcium carbonate-infused backing board, and they also are supported by plastic that sometimes doesn't lay completely flat. Heck, I'd be far more concerned about the potential negative impact on the hobby of long term storage of otherwise high grade comics in CGC slabs (of which there are a lot) than I would the effects of localized pressing (of which there are relatively few). In particular, I'm concerned that encapsulated books might run serious risks over the long term for both acid-driven paper deterioration, and inner well-driven warping.

[FFB]

It would be easier and likely a lot more fruitful to talk to some of the people who have written articles for the Journal of the AIC regarding paper permanence to see if they'd be interested in doing research along these lines. There is a zero percent chance that CGC will fund this research (why would they?) and I can't see how this issue could be used to create an attractive program for Mythbusters, either.

 

I can't imagine them having razor thin profit margins, considering the percentage and frequency of high end books they process. Since they aren't public, we can't see the actual profit margins, but c'mon how much overhead can a small outfit like that have?

I would suspect they are making HUGE profit margins off the high end books, more than enough to compensate for time spent on some lower tier items.

Heck they could donate a pittance to some local university to get grad students to do a study.

 

There was (I don't know if it still runs) a program that had two guys run all kinds of experiments to verify myths, yeah it was called mythbusters. They usually liked to blow things up or tear things apart, but on one episode they tried to see if they could rebuild a phonograph needle from a piece of glass or something. Someone should contact them to do a segment on effects of pressing and sturdiness of plastic encapsulation (explosives part).

 

 

 

If I was to approach it from a scientific point of view, I would tend to think spectroscopy would be a good starting point. It seems fairly well established as a tool to determine the characterization (including degradation) of paper.

 

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THN-4VGF3T5-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=922f4899ab672f98ae6e1806deecbcc9

 

http://aic.stanford.edu/sg/bpg/annual/v10/bp10-06.html

 

Considering how much money CGC has for R&D, they should easily be able to afford such a tool or outsource to a consulting firm to run some statistical studies on this (if they wanted to).

 

Unfortunately, CGC has no money at all for R&D. Supposedly, they can barely turn a profit flipping books in and out the door as fast as humanly possible. The only alterations in the product over the years have been with the inner well design, and these likely were done on a trial-and-error basis. Today's spectrometers are powerful devices for analyzing the chemical composition (and decomposition) of materials, but they typically run five figure dollars to purchase, and require skilled, well-trained technicians to operate.

 

While we're discussing the long-term consequences of comic book pressing, it would be worthwhile to consider also long-term effects of encapsulation in CGC slabs. The books lack the acid buffering that comes from a good, calcium carbonate-infused backing board, and they also are supported by plastic that sometimes doesn't lay completely flat. Heck, I'd be far more concerned about the potential negative impact on the hobby of long term storage of otherwise high grade comics in CGC slabs (of which there are a lot) than I would the effects of localized pressing (of which there are relatively few). In particular, I'm concerned that encapsulated books might run serious risks over the long term for both acid-driven paper deterioration, and inner well-driven warping.

[kc120us]

Great thread, guys. Very informative. Thank you. (thumbs u

[bronze_rules]

Those guys (mythbusters) love explosives. Just tell them there is a myth that encapsulated comics can withstand a small explosion and preserve their state, all the other stuff will be just the peripheral 20 minute filler material (for which they will need the paper cons. experts).

 

Seriously though, I think you and others have already hit the proverbial nail on the head; which is CGC does not care to find out the results (or if they have already, they aren't divulging). Why would they? I suppose because that is one of their advertised functions; to determine if comics have been artificially restored for the buyers and sellers who are paying for that service. It's more of a philosophical issue which I won't go into any more on this thread.

 

But, agreed, your suggestion is another alternative.

 

I do have a specific question for you. You often mentioned that 'many' pressing techniques are not heat, nor moisture/steam driven. Rather than state anecdotal cases here and there, if you had to specifically come up with an estimate of what the average percentage of pressing (70s and older) is applied via heat/moisture/steam vs completely dry/cold pressing (across the industry, not just yourself), how would you break down that number? I.e. 50% heat/steam 50% dry/cold. Ignore any other constraints, just focus on those two classes. My guess is there is a larger percentage in the heat/steam category, but again, I defer to your experience.

 

Also, there must be some standard type of press equipment that typical comic conservators use. Any way you could point to an online supplier's catalog or list some of the major pressing machinery/manufacturers (if that is proprietary, then no problem; don't divulge).

 

 

It would be easier and likely a lot more fruitful to talk to some of the people who have written articles for the Journal of the AIC regarding paper permanence to see if they'd be interested in doing research along these lines. There is a zero percent chance that CGC will fund this research (why would they?) and I can't see how this issue could be used to create an attractive program for Mythbusters, either.

 

I can't imagine them having razor thin profit margins, considering the percentage and frequency of high end books they process. Since they aren't public, we can't see the actual profit margins, but c'mon how much overhead can a small outfit like that have?

I would suspect they are making HUGE profit margins off the high end books, more than enough to compensate for time spent on some lower tier items.

Heck they could donate a pittance to some local university to get grad students to do a study.

 

There was (I don't know if it still runs) a program that had two guys run all kinds of experiments to verify myths, yeah it was called mythbusters. They usually liked to blow things up or tear things apart, but on one episode they tried to see if they could rebuild a phonograph needle from a piece of glass or something. Someone should contact them to do a segment on effects of pressing and sturdiness of plastic encapsulation (explosives part).

 

 

 

If I was to approach it from a scientific point of view, I would tend to think spectroscopy would be a good starting point. It seems fairly well established as a tool to determine the characterization (including degradation) of paper.

 

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THN-4VGF3T5-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=922f4899ab672f98ae6e1806deecbcc9

 

http://aic.stanford.edu/sg/bpg/annual/v10/bp10-06.html

 

Considering how much money CGC has for R&D, they should easily be able to afford such a tool or outsource to a consulting firm to run some statistical studies on this (if they wanted to).

 

Unfortunately, CGC has no money at all for R&D. Supposedly, they can barely turn a profit flipping books in and out the door as fast as humanly possible. The only alterations in the product over the years have been with the inner well design, and these likely were done on a trial-and-error basis. Today's spectrometers are powerful devices for analyzing the chemical composition (and decomposition) of materials, but they typically run five figure dollars to purchase, and require skilled, well-trained technicians to operate.

 

While we're discussing the long-term consequences of comic book pressing, it would be worthwhile to consider also long-term effects of encapsulation in CGC slabs. The books lack the acid buffering that comes from a good, calcium carbonate-infused backing board, and they also are supported by plastic that sometimes doesn't lay completely flat. Heck, I'd be far more concerned about the potential negative impact on the hobby of long term storage of otherwise high grade comics in CGC slabs (of which there are a lot) than I would the effects of localized pressing (of which there are relatively few). In particular, I'm concerned that encapsulated books might run serious risks over the long term for both acid-driven paper deterioration, and inner well-driven warping.

[stagedoorjohnny]

 

What are you basing that statement on? There is quite a bit of scientific evidence that suggests that it is acidity, and not necessarily the lignin content of the paper, that determines paper strength and permanence upon aging. Springhill Offset is alum-rosin sized, which means it is inherently acidic. I will grant you that high lignin content paper tends to react more with atmospheric pollutants than lignin free paper, but that's why it's not appropriate to compare the Springhill Offset results 1:1 with high lignin content groundwood. But that does not mean you should make the logical leap that we can learn nothing from the Springhill Offset results and simply disregard them as though high lignin content paper will react the opposite way upon aging. It simply means that they will age at different rates, with the high lignin content paper aging faster.

 

 

The process and chemistry of making newsprint versus freesheet is so different. Depending on when that test was done, the brightness on that Springhill Offset was either 83 bt., 86 bt., or what it is today, 90 bt. Offset standards have changed through the years. In comparison, newsprint today is 59-60 bt. And back as recent as the 1970's, it was 56 bt. That is a huge difference in brightness and the amount and types of chemicals used in the process to "whiten" the sheet are very different. I understand the acidity, but there are lots of differences in composition besides that and I can't imagine them not having an impact. Can you get a ratio? I don't know, perhaps. But in order to get one, you have to test the newsprint and the coated groundwood. And if you do that, you have a much better answer regardless of the freesheet test.

 

Are there any tests out there on newsprint and/or coated groundwood? How about those two grades from samples manufactured in the 1940's or 50's? The grade standards were a little different then, so it could make a difference within similar grades. Either one of those I would love to see. But even those wouldn't be a "be all end all" because of all the variables involved. But I'd rather slice and disect that one.

[divad]

 

What are you basing that statement on? There is quite a bit of scientific evidence that suggests that it is acidity, and not necessarily the lignin content of the paper, that determines paper strength and permanence upon aging. Springhill Offset is alum-rosin sized, which means it is inherently acidic. I will grant you that high lignin content paper tends to react more with atmospheric pollutants than lignin free paper, but that's why it's not appropriate to compare the Springhill Offset results 1:1 with high lignin content groundwood. But that does not mean you should make the logical leap that we can learn nothing from the Springhill Offset results and simply disregard them as though high lignin content paper will react the opposite way upon aging. It simply means that they will age at different rates, with the high lignin content paper aging faster.

 

 

The process and chemistry of making newsprint versus freesheet is so different. Depending on when that test was done, the brightness on that Springhill Offset was either 83 bt., 86 bt., or what it is today, 90 bt. Offset standards have changed through the years. In comparison, newsprint today is 59-60 bt. And back as recent as the 1970's, it was 56 bt. That is a huge difference in brightness and the amount and types of chemicals used in the process to "whiten" the sheet are very different. I understand the acidity, but there are lots of differences in composition besides that and I can't imagine them not having an impact. Can you get a ratio? I don't know, perhaps. But in order to get one, you have to test the newsprint and the coated groundwood. And if you do that, you have a much better answer regardless of the freesheet test.

 

Are there any tests out there on newsprint and/or coated groundwood? How about those two grades from samples manufactured in the 1940's or 50's? The grade standards were a little different then, so it could make a difference within similar grades. Either one of those I would love to see. But even those wouldn't be a "be all end all" because of all the variables involved. But I'd rather slice and disect that one.

 

Good stuff Johnny - keep it up

[FFB]

 

What are you basing that statement on? There is quite a bit of scientific evidence that suggests that it is acidity, and not necessarily the lignin content of the paper, that determines paper strength and permanence upon aging. Springhill Offset is alum-rosin sized, which means it is inherently acidic. I will grant you that high lignin content paper tends to react more with atmospheric pollutants than lignin free paper, but that's why it's not appropriate to compare the Springhill Offset results 1:1 with high lignin content groundwood. But that does not mean you should make the logical leap that we can learn nothing from the Springhill Offset results and simply disregard them as though high lignin content paper will react the opposite way upon aging. It simply means that they will age at different rates, with the high lignin content paper aging faster.

 

 

The process and chemistry of making newsprint versus freesheet is so different. Depending on when that test was done, the brightness on that Springhill Offset was either 83 bt., 86 bt., or what it is today, 90 bt. Offset standards have changed through the years. In comparison, newsprint today is 59-60 bt. And back as recent as the 1970's, it was 56 bt. That is a huge difference in brightness and the amount and types of chemicals used in the process to "whiten" the sheet are very different. I understand the acidity, but there are lots of differences in composition besides that and I can't imagine them not having an impact. Can you get a ratio? I don't know, perhaps. But in order to get one, you have to test the newsprint and the coated groundwood. And if you do that, you have a much better answer regardless of the freesheet test.

 

Are there any tests out there on newsprint and/or coated groundwood? How about those two grades from samples manufactured in the 1940's or 50's? The grade standards were a little different then, so it could make a difference within similar grades. Either one of those I would love to see. But even those wouldn't be a "be all end all" because of all the variables involved. But I'd rather slice and disect that one.

 

So would I (that's why tb's experiment sounds so interesting), but we are getting far afield of the original point that fantastic_four raised when he started the thread. The question was whether a typical dry mount press job would cause "long term damage" to a comic. My point was that it will cause at most negligible damage on a molecular level, but nothing appreciable in terms of fold strength, suppleness, tear strength, or any other test of paper freshness or strength. It doesn't seem like you're disputing that, right?

 

Anyway, if you want some data for testing newsprint from the 1970s exposed to accelerated aging, this 1979 study from the JAIC has some data. http://aic.stanford.edu/jaic/articles/jaic18-02-001_3.html It took about 17 days for the unwashed sample (the control sample) of newsprint to turn brittle when aged in a 90C 50%RH oven.

 

If you look at the plot line for the 90C/50%RH sample in the Library of Congress tests for the Springhill Offset paper and follow it to the bottom of the graph (where it would endure zero folds), it took about 17 days for the Springhill Offset to get there. So really, the accelerated aging tests show that the Springhill Offset paper performs pretty closely to 1970s newsprint, despite all of the differences in methods of manufacture, brightness levels, etc.

 

I'll grant you that newsprint quality varied from publisher to publisher over the decades, but all of this misses the point. The point is that I do not believe that a few minutes at 60-65C in a dry mount press is going to cause appreciable damage to the paper strength, even if you have to introduce humidity to relax the fibers to remove a warp. Whatever damage is caused by a few minutes in the press is going to be dwarfed by the damage caused by whoever owns the book and doesn't store it in ideal conditions over the next 30 years.

[RockMyAmadeus]

You aren't going to find that smoking gun article. The question you're asking may seem like a deep, scientific issue for you, but for a conservator, whether or not to press an artifact tends not to be a huge internal struggle. Their scholarly articles will deal with far more sophisticated topics. Pressing is "Conservation 101."

 

 

Thank you for your many posts in this thread. They have been thoroughly enjoyable, and totally lacking in insult. Thank you!