Are "acid-free" backing boards truly acid-free? Time to pH test & find out! 13 13

[selegue]

... To support his position, Drew stated that the pH level of calcium carbonate is 9.5 to 9.75, and that the pH level of the coated surface of the BCW Comic Backing Board was 7.0. His reasoning was that if the calcium carbonate didn't absorb some of the acid from the SBS board then he would expect the coated surface to also be at the 9.5 to 9.75 level. In all fairness, Drew was going from memory and he was fairly close. Upon checking I found that calcium carbonate has a pH level of 9.0. However, during our discussion about the nature of the coating on the SBS board (which I will address in a moment), Drew stated that he didn't believe that the coating was comprised of pure calcium carbonate. If he is correct, that might explain why the pH level of the coated board is 7.0 (as indicated by the data presented in Mike's study) rather than pH 9.0....

 

I was going to give up on this thread, but it's starting to make sense! I'm glad to see that you were able to communicate.

 

Statements above that are not quite correct: "the pH level of calcium carbonate is 9.5 to 9.75" and "calcium carbonate has a pH level of 9.0." I'm not sure what that means, since pH is a property of an aqueous solution, not a solid. The pH of a solution depends on the concentration of acid or base in the solution.

 

Whoever doesn't want to read technical details can skip this part.

 

What matters is the pKa (equilibrium constant) of the acid or base. Carbonate has two pKa values, 6.4 for carbonic acid <-> bicarbonate and 10.3 for bicarbonate <-> carbonate

 

If I quickly did the calculations right, a one-molar solution of calcium carbonate (it's not really that soluble) would have a pH of about 12.2. A one-molar solution of calcium bicarbonate (HCO3- from adding one H+ to carbonate) would have a pH of about 10.4. Can you tell me where the numbers 9.0 and 9.5-9.75 came from? That would be close to the pH of a 0.1-M solution of calcium bicarbonate.

 

While I'm waxing technical, the Lewis acid/base description -- I don't remember who brought it up -- has almost nothing to do with this discussion. This is all Brønsted-Lowry acid/base.

 

The coatings you're discussing almost certainly have a binder in addition to calcium carbonate, or it would simply flake off like chalk dust.

 

Jack

 

 

 

 

 

 

 

[BCW Supplies]

Good points, Mike. I am now wondering about a few things between the definitions from the glossary of the Guidelines for Information About Preservation Products, your comments, and the test results. I'm certainly not going to argue about the meaning of the word in where the definition of alkaline reserve is concerned. But, the test results indicate that the alkaline reserve in the BCW Current Board is 4.36% and the glossary of the Guidelines for Information About Preservation Products uses the term alkaline reserve and buffer interchangeably.

 

The statement "However free of acid a paper or board may be immediately after manufacture, over time the presence of residual chlorine from bleaching, aluminum sulfate from sizing, or pollutants in the atmosphere may lead to the formation of acid unless an alkaline substance is added to the paper or board." does not seem to exclude the coating applied after the board is manufactured, and it doesn't seem to be specific about the amount of the alkaline substance that is added.

 

Regarding your second point, your conclusions were that 1.) the coating on a regular backing board wears off over time, and 2.) that this doesn't happen with boards manufactured by E. Gerber or Bill Cole. So, essentially I think you're correct. But, I have a couple of thoughts on this. First, I'm not sure I would use the term "wears off" relative to the coating. I think I would use the term "becomes saturated" in reference to the calcium carbonate. I believe that the boards are all made using a sulfate manufacturing process (it is my understanding that boards manufactured using the sulfite process are not white, they are gray throughout). So, whether or not this ever happens to the E. Gerber or Bill Cole product would depend on whether or not there was enough calcium carbonate to absorb all of the residual acid contained in the E. Gerber or Bill Cole board. If 3% is more than enough to absorb all of the residual acid contained in the board then your right. If there is more residual acid in the board that the buffer can absorb then at some point even the E. Gerber or Bill Cole board would become acidic.

 

In reference to your comment about doing the hot extraction test a couple of months after the board is manufactured, I think we would have to seal a board completely in a material such as polyester to be sure that it didn't react with the pollutants in the air and then do the hot extraction test. That should tell us whether or not the acid from the board itself is being absorbed by the calcium carbonate. Mr. Blackburn suggests that "a stabilized acid base process sheet of paper will not absorb any significant level of alkaline content from the coating" so it would be interesting to see if this is true.

 

And finally, regarding your statement that you still don't see how we can call the board "acid free" I'll refer back to my comments above about the test results and the definitions of alkaline reserve, buffer, and acid free, as stated in the glossary of the Guidelines for Information About Preservation Products. The test results indicate that the pH level of the BCW Comic Board is 8.01, the alkaline reserve is 4.36%, and the glossary of the Guidelines for Information About Preservation Products uses the terms alkaline reserve and buffer interchangeably. Perhaps the definitions in the glossary of the Guidelines for Information About Preservation Products need to revised. One thing is for sure; if Drew worked at the National Information Standards Institution, they would have been worded differently.

[BCW Supplies]

Can you tell me where the numbers 9.0 and 9.5-9.75 came from?

Yes sir, I can. Drew's pH level of 9.5 to 9.75 came from memory, and when I asked him what his reference was during our phone conversation today he couldn't remember where it came from. I mistakenly gave the pKa value as the pH level. Thanks for your help with this. :thumbsup:

[selegue]

Can you tell me where the numbers 9.0 and 9.5-9.75 came from?

Yes sir, I can. Drew's pH level of 9.5 to 9.75 came from memory, and when I asked him what his reference was during our phone conversation today he couldn't remember where it came from. I mistakenly gave the pKa value as the pH level. Thanks for your help with this. :thumbsup:

 

?

 

"Carbonate has two pKa values, 6.4 for carbonic acid <-> bicarbonate and 10.3 for bicarbonate <-> carbonate "

 

Neither pKa = 9.0.

 

JPS

[BCW Supplies]

Molecular formula CaCO3

Exact mass 100.0869 g/mol

Appearance Fine white powder

Density 2.71 g/cm3 (calcite)

2.83 g/cm3 (aragonite)

Melting point

825 °C (aragonite)

1339 °C (calcite)[2]

Boiling point

decomposes

Solubility in water 0.00015 mol/L (25°C)

Solubility product, Ksp 4.8×10−9[1]

Solubility in dilute acids soluble

Acidity (pKa) 9.0

Refractive index (nD) 1.59

 

http://en.wikipedia.org/wiki/Calcium_carbonate

 

I guess that goes to show you can't always rely on wikipedia.

[selegue]

 

Acidity (pKa) 9.0

 

http://en.wikipedia.org/wiki/Calcium_carbonate

 

I guess that goes to show you can't always rely on wikipedia.

 

That's puzzling -- usually the technical wikipedia pages are pretty accurate. I wonder what the writer meant by defining the pKa of CaCO3 that way. It doesn't have a proton, so it doesn't have a pKa.

 

JPS

[selegue]

 

 

....In addition, Drew contends that that the SBS board does not absorb any significant level of residual acid from a comic book because most of the calcium carbonate coating has been saturated by the board itself. My response was that, if he were correct, the SBS board would turn yellow while still sealed in the package. To support his position, Drew stated that the pH level of calcium carbonate is 9.5 to 9.75, and that the pH level of the coated surface of the BCW Comic Backing Board was 7.0. His reasoning was that if the calcium carbonate didn't absorb some of the acid from the SBS board then he would expect the coated surface to also be at the 9.5 to 9.75 level. In all fairness, Drew was going from memory and he was fairly close. Upon checking I found that calcium carbonate has a pH level of 9.0. However, during our discussion about the nature of the coating on the SBS board (which I will address in a moment), Drew stated that he didn't believe that the coating was comprised of pure calcium carbonate. If he is correct, that might explain why the pH level of the coated board is 7.0 (as indicated by the data presented in Mike's study) rather than pH 9.0....

 

I truly believe that by the end of the conversation Drew understood that we are not here to mislead anyone. We are here for the same reason that he an Mike are here; to determine, beyond any doubt, the truth about SBS as it relates to comic backing boards. And, that we each believe in the conclusions that we have drawn from the data that Mike has presented. And further, that we need to work together to determine what tests are required to prove one hypothesis or the other for the benefit of everyone concerned.

 

I'm going back and forth about whether storing the boards alone would be a proper test.

 

The problem is that acidic pulp paper autocatalyzes its own decomposition. That is, the volatile acids, especially acetic acid (the "old comic book smell" that some collectors love is mostly acetic acid and mildew) causes further breakdown of cellulose, leading to crumbling and yellowing. If there is no pulp paper present to produce acetic acid and start the cycle, the board alone probably won't break down as quickly as it would with the paper present.

 

There is some good information at the Library of Congress site

 

Index

 

If you want to see actual headspace measurements, see here and here.

 

With those references, I'm sure we've gotten too technical for this forum.

 

Good luck!

 

Jack

 

 

[InvstmntComcSuply]

I did have a conversation with Ken yesterday, although the specifics of the conversation vary somewhat from his description. Some of that variance is normal personal interpretation and some is just Ken being a salesman. To clarify:

 

Ken mentioned a couple of times that I "urged him to address" items. This is couldn't be further from the truth. As, I am sure he will attest, he doesn't need any outside encouragement.

 

Ken minimizes my concerns, which were not product specific. My concerns were that most of his assumptions were flawed, his arguments misleading and his conclusions inaccurate.

 

The following was not part of the conversation

Neither one of us are sure to what degree the E. Gerber Archival Mat Boards absorb the residual acid that migrates from a comic book, but we have agreed that we should work together to determine what testing methods should be used to demonstrate the degree to which E. Gerber Archival Mat Boards absorb acid.

The closest thing to this was my suggestion to have independent testing done on the various manufacturers boards with an emphasis that the boards should be "bought off the shelf at a comic shop" to approximate aging. I have no concerns whatsoever about the Gerber or Cole board. Buffered throughout boards such as Gerbers and Coles are the standard used by conservators everywhere for ephemera. I also specifically declined comment about Cole's extenders, because I have little knowledge about the product. I pointed out that Ken should have done likewise with the entire thread.

 

One of the points that we discussed is my conclusion, based on the data in Mike's study, that the acid from the SBS board does not migrate to the comic book. This conclusion is based on the fact that the pH level of the uncoated side of the new BCW Comic Backing Board was unchanged after two years of use.

 

I explained why the above is not "a fact", this is an inaccurate conclusion.

 

Further, that my conclusion is supported by Mr. Blackburn's statement that "a stabilized acid base process sheet of paper will not absorb any significant level of alkaline content from the coating."

 

The above doesn't agree with the data

 

 

Drew stated that he didn't believe that the coating was comprised of pure calcium carbonate. If he is correct, that might explain why the pH level of the coated board is 7.0 (as indicated by the data presented in Mike's study) rather than pH 9.0.

 

That would not come close to explaining why the pH of the coating was 7

 

 

Regarding Ken's use of the term "buffered" with the BCW "coated" board:

I challenged Ken yesterday to find a reputable manufacturer who claimed their product was "buffered" but had ANY layer which was acidic, let alone at least 95% (Ken's number, I think it is a significantly higher percentage) of the board.

 

I am in a time crunch and will have to address the rest this evening.

 

[Snake Eyes]

Very interesting, although admittedly a little bit over my head with some of the technical jargon. Nonetheless, the information here may affect how I choose to store my comics going forward. That leads to a question...folks asked a number of times who Ken was prior to Drew's call. I am glad that is clear now, as I believe one must consider the source of information. Having taken several graduate classes in statistics, I did learn that numbers can pretty much be manipulated in a way that the same data set can yield very differing conclusions based on the statistician processing it.

 

So that leads to my question on the other side of the equation. I notice in Drew's signature line is a link to a sales thread selling Gerber products. So to keep the argument fair, I was curious if you could discuss what relationship you have, if any with that company (direct employ, resale, nothing, etc., etc.). Anyway, appreciate all the information you guys are providing and it certainly has given me food for thought (thumbs u

[BCW Supplies]

I did have a conversation with Ken yesterday, although the specifics of the conversation vary somewhat from his description. Some of that variance is normal personal interpretation and some is just Ken being a salesman.

I have to agree with this. I did the best I could to detail the conversation, but it was an hour and a half and there was a lot of information exchanged. Also, several hours elapsed before I was able to post.

 

Ken mentioned a couple of times that I "urged him to address" items. This is couldn't be further from the truth. As, I am sure he will attest, he doesn't need any outside encouragement.

This may be a result of the variance of interpretation Drew mentions. Perhaps "suggested" would be a better word. But, I don't think it matters much to the point of the conversation.

 

Ken minimizes my concerns, which were not product specific. My concerns were that most of his assumptions were flawed, his arguments misleading and his conclusions inaccurate.

From what I took away from the conversation, it was all of these. Again, I'm not sure it matters much to the point of the discussion, but I'm glad that Drew stated his position just the same.

 

The following was not part of the conversation

Neither one of us are sure to what degree the E. Gerber Archival Mat Boards absorb the residual acid that migrates from a comic book, but we have agreed that we should work together to determine what testing methods should be used to demonstrate the degree to which E. Gerber Archival Mat Boards absorb acid.

The closest thing to this was my suggestion to have independent testing done on the various manufacturers boards with an emphasis that the boards should be "bought off the shelf at a comic shop" to approximate aging. I have no concerns whatsoever about the Gerber or Cole board. Buffered throughout boards such as Gerbers and Coles are the standard used by conservators everywhere for ephemera. I also specifically declined comment about Cole's extenders, because I have little knowledge about the product. I pointed out that Ken should have done likewise with the entire thread.

These items were part of the conversation from my side of it. But again, there was a lot of information discussed. And, as Drew pointed out, there will be some variance in the interpretation. I certainly agree that I should not have commented on the Bill Cole product. And, I do hope that Drew is not implying that we can't work together to determine which testing methods will help us determine which conclusions are correct.

 

One of the points that we discussed is my conclusion, based on the data in Mike's study, that the acid from the SBS board does not migrate to the comic book. This conclusion is based on the fact that the pH level of the uncoated side of the new BCW Comic Backing Board was unchanged after two years of use.

I explained why the above is not "a fact", this is an inaccurate conclusion.

Good point. It is not a fact, but rather, one of the main points where we differ in our opinion about the conclusion. Further, it is one of those things that we should test to determine which conclusion is correct.

 

Further, that my conclusion is supported by Mr. Blackburn's statement that "a stabilized acid base process sheet of paper will not absorb any significant level of alkaline content from the coating."

 

The above doesn't agree with the data.

Again, I believe this is one of the main points that we disagree on. That is, whether the calcium carbonate absorbs any significant amount of acid from the board itself. And, we should find a way to test to see which hypothesis is correct. This test is what I was referring to about sealing a board in polyester for some period of time before doing the hot extraction test when I was responding to Mike.

 

Drew stated that he didn't believe that the coating was comprised of pure calcium carbonate. If he is correct, that might explain why the pH level of the coated board is 7.0 (as indicated by the data presented in Mike's study) rather than pH 9.0.

 

That would not come close to explaining why the pH of the coating was 7

I think that would depend greatly on how stable the core board is, how much of the coating is actually calcium carbonate, and what else the coating is comprised of. Jack has stated that the coating can't all be calcium carbonate or it would flake off. I'm sure he's right about that.

 

Regarding Ken's use of the term "buffered" with the BCW "coated" board:

I challenged Ken yesterday to find a reputable manufacturer who claimed their product was "buffered" but had ANY layer which was acidic, let alone at least 95% (Ken's number, I think it is a significantly higher percentage) of the board.

What another manufacturer claims or doesn't claim about their product is not relative to ours. What is pertinent in this case is whether or not our board meets the description of "acid free" as defined by the National Information Standards Institution in the Guidelines for Information About Preservation Products.

[thunderstick]

...So that leads to my question on the other side of the equation. I notice in Drew's signature line is a link to a sales thread selling Gerber products. So to keep the argument fair, I was curious if you could discuss what relationship you have, if any with that company (direct employ, resale, nothing, etc., etc.)...

Irrelevant.

 

Please read the entire thread.

[Snake Eyes]

...So that leads to my question on the other side of the equation. I notice in Drew's signature line is a link to a sales thread selling Gerber products. So to keep the argument fair, I was curious if you could discuss what relationship you have, if any with that company (direct employ, resale, nothing, etc., etc.)...

Irrelevant.

 

Please read the entire thread.

 

To you perhaps...I did read the entire thread over the last several days so perhaps I missed something. Quite simply it is relevant to how I will process the information, so I still would prefer to know.

 

I do appreciate your trying to decide what may or may not be useful information for me to consider though

[ComicDoc]

Wow, what a great and insightful if not "inciting" discussion!!

 

First let me say that I have been using the BCW products for years (I was using mylar and acid free boards and boxes in the late 70's and 80's with my original collection too one of only a handful back then.). I have to first state that the service and responsiveness from the company has been great and shipping more reasonable than others. I did a comparison of all the large suppliers back when I restarted collecting over 10 years ago and must say that I prefer BCW to the others for most supplies but I use EGerber’s Mylite2 and FB which I get directly from them.

 

Not a fan of the poly bags and the SBS boards but do use them for poor or "modern" books as neither require or warrant the amount of attention my SA and BA/CA books do. I think that Hotflips makes a better resealing bag because it is thicker and holds its shape better. I did get a set of discontinued bags from BCW that were great but were discontinued!!

 

Reference the boards I have been using the extenders and love the support that they confer to the books which prevents spine creases. I have been concerned about staple damage and addressed this by using one size smaller than recommended and only up to two per book. After years of use I have not had any appreciable changes in staple integrity. Also no creases or signs of wear on the covers from the boards have become apparent but I am watching.

 

I have changed my usage as of late; before I would use two extenders and one microchamber sheet per book. Now I have reversed this to two microchamber sheets and one extender in the middle of the book. My reasoning, although not as erudite as the discussion above, was based on Mike's testing and Drew's ability to provide microchamber sheets at a reasonable cost. I have a very large collection > 20K books and vast majority are stored as such: Two extenders (front and back) and one microchamber in the center enclosed in a Mylite2 with EGerber Full back. I even store my treasury books and magazines this way (yup had Mylar bags made for my treasury books - bagsunlimited). As I go through my collection I am changing this to MCs front and back cover and extender in the middle of the book.

 

My thinking as a quasi scientist (the PhDs in the group tend to look down on us physicians when call ourselves scientists!! I use to be the Medical Director at a research lab and the sanitation engineer was treated better!!) after reviewing all the data I do not feel that the "danger" from the extenders in the middle of the book is very great. Essentially, if it absorbs even a little but does not release anything I am happy. I think the benefit of having increased the sturdiness of the book and prevention of spine creases out weighs any theoretical risk. I think that my new arrangement is the perfect set up balancing all my concerns. I guess if I could afford the BCE Xtenders I would use them in lieu of the BCW extenders but I cannot and therefore am satisfied with my cost – risk – benefit analysis. I have always thought that the EGerber boards were essentially inert which was fine but do remember being told that they do absorb the contaminants from the enclosed environment of the Mylar sleeve if sealed. That is why I have always sealed all my bags with acid free removable tape and after >10 years of storage my books do not have any browning of the top, yellowing of pages etc.

 

In reference to Mr. Kellem's email, I did infer that he was speaking as a technical expert and that the information provided was specifically about the BCW product and not industry speak! So lesson learned, not to be so trusting although it is my nature when it comes from what I thought was a reputable source.

 

I think Mr. O'Brien has done a very good job of explaining the BCW position and that their boards are not for long term storage.

 

I do have to ask how they can state that the extenders: "Prevents yellowing, Prevents acids, mold, & mildew and reacts to corrosive gases" As none of the information present heretofore addresses a test that proves these claims. Now I understand that one can extrapolate to a certain degree but these are specific claims about the boards. I would like to know how they were derived.

 

I think it would be useful to do these tests and present the data to be reviewed by all. It is possible to adjust the atmosphere (not my expertise but know that we can artificially alter the environment to give us an equivalent of ten years of storage and or exposures) and to see under these conditions how much of certain acid is absorbed by the boards; exactly what is the active process by which yellowing is prevented; mold and mildew are prevented or eliminated etc.

 

I do want to thank you all for attention to this matter; as I and others do rely on your expertise to preserve our collections for future generations to enjoy!

 

Sincerely,

 

Bernard

 

 

 

 

[mschmidt]

I have changed my usage as of late; before I would use two extenders and one microchamber sheet per book. Now I have reversed this to two microchamber sheets and one extender in the middle of the book. My reasoning, although not as erudite as the discussion above, was based on Mike's testing and Drew's ability to provide microchamber sheets at a reasonable cost. I have a very large collection > 20K books and vast majority are stored as such: Two extenders (front and back) and one microchamber in the center enclosed in a Mylite2 with EGerber Full back. I even store my treasury books and magazines this way (yup had Mylar bags made for my treasury books - bagsunlimited). As I go through my collection I am changing this to MCs front and back cover and extender in the middle of the book.

 

Bernard: there's absolutely no reason for you to be using the BCW Extender in this configuration.

 

As a matter of fact, you're actually making the conservation environment worse by introducing the Extender into this, seeing that the Extender is no more than a thin SBS backing board with a coating on both sides which will, in fact, become acidic over time.

 

You're already doing everything else correctly - a Mylites2 with a Gerber full-back and a piece (or two) of micro-chamber paper is pretty much the optimal storage solution barring any outside influences (temperature/humidity variations, exposure to direct light, etc). Seeing that neither the full-back nor the micro-chamber paper will ever become acidic, you really don't want to introduce another element into this environment that will.

[ComicDoc]

did not think about the board becoming acidic back to the drawing board! How long before the board becomes acidic??

 

Now what to do with all these boards???

Edited June 22, 2011 by ComicDoc

[BCW Supplies]

Hello Bernard,

 

The BCW Comic Extenders are not intended for long term storage. They should be changed every 3 to 5 years. They are intended to be a cost effective alternative to Bill Cole's product, but as Mike points out, it is not the same thing. As I stated way back in this thread, we believe that MCP and polyester (Mylar and Mellinex are brand names of polyester) are the way to go. So, as Mike said, for long term storage you're already doing the right thing, but the BCW Comic Extenders are not a long term solution.

 

Did I understand you correctly? You got the impression from Dana Kellum that a BCW Comic Extender prevents mold and mildew? I guess I need to go back through the thread where you asked about using them as I did not read the entire thing. One thing is interesting, though. The anecdotal evidence that you provide seems to contradict the theory that BCW Comic Extenders "are certain to cause undue strain on the staples which can lead to the staples popping through the paper."

[ComicDoc]

Yes, it is stated in the email he sent me on November 13, 2006:

 

Hi Buddy

 

Our product

 

. Prevents yellowing

. Prevents acids, mold, & mildew

. Reacts to corrosive gases ......

 

Dana Kellum

Manager Internet Sales

 

BCW Diversified, Inc.

 

(765) 644-2033 ext 13

(800) 433-4229

 

He (Mr. Kellum) had also stated in a different email that he had put one in between each page of a book and corrected a mold / mildew problem!

 

I have not noted a stress or strain to my staples as of yet, but do use the smaller size and only two per book. Also I am not talking about the strain that would be scrutinized at the 9.0 and above level which is where this concern would be most destructive. I am talking about my average level which is 6 (Fine) to 8 (Very Fine) and lower than 6.0 even less concern. As I will be removing these boards over the coming year I will not be able to give you a long term evaluation.

[Aman619]

as Lou Costello famously said in a similar conversation:

 

THOID BASE!

[BCW Supplies]

Now that you mention it, I did see that. I was responding to Drew regarding the comparison that Dana was making for you when he was quoting the Royal Art Salon and I did not read that part very closely. I apologize, and I just checked our web site to make sure the same claim wasn't being made there. I will be speaking to Mr. Kellum about that very quote tomorrow morning.

 

As for a long term evaluation, there's no need. I wouldn't want you leaving the Extenders in your books for more than 3 to 5 years. Since both sides are coated and the alkaline reserve is approximately 10% the books will be fine for a while. But, you're better off with MCP. And, while we're on the topic, in my research I found that MCP has 200 times more buffer capacity than regular comic boards.

[InvstmntComcSuply]

We specialize in archival storage products and are a distributor for Gerber. The Gerber Mylites2 are a great complement to our pre-cut comic sized Microchamber interleaving paper (the .0025" thick, cotton version that CGC uses, rather than the thicker pulp based).

 

Halfbacks and Fullbacks make up less than 2% of our sales as we are handicapped by having to ship them twice, since Gerber doesn't drop ship. We regularly recommend customers buy larger board quantities direct from the factory, although we are not compensated for those sales.