Should Not Prints Be Buffered?

[dancqu]

If mounting boards and mats are buffered
should not the print itself? Seems only
reasonable. Dan

 

[Donmck]

I'm not a chemist,but I think the baryta layer(barrium sulfate) is dead neutral ---- and is the buffer between the paper and the silver image.
Mat board is usually buffered by the addion of cal.carb.

-Don

 

[Photo Engineer]

FB photo papers are buffered, and the emulsions are buffers in the sense that the gelatin is a buffer. Proper processing will leave them in a good condition for keeping.

PE

 

[Ray Rogers]

If mounting boards and mats are buffered
should not the print itself? Seems only
reasonable. Dan

Yes, but...
One shoe doesn't fit all feet.
I guess you are talking about regular B/W prints...
There are floating lists of which general process types are best buffered and which are best unbuffered... the choice is more complicated than one might at first guess, but the last I looked at it, your conclusion works,
but not because the matt/boards are buffered...
those boards are best buffered for themselves, not for what they will hold.
(which could be practically anything)

Ray

 

[BetterSense]

FB photo papers are buffered,

What of RC papers?

 

[Photo Engineer]

What of RC papers?

No need. There is no contact with the paper base in the sandwich.

PE

 

[AgX]

In the RC papers the PE itself has to be `buffered´ in the meaning of containing anti-oxidants to avoid degradation due to TiO2 photocatalytic action.

 

[papermaker]

The OP asked should not prints be buffered since mount and matt boards are. It seems clear that the use of the word buffered in this case refers to the use of a carbonate (calcium carbonate, for example) in the board to create an alkaline reserve that will absorb acids that might come in contact with a print.

A follow-up post by someone else noted that there exist lists of general types of papers, photo and otherwise, that should not be used with buffered products. A quick survey of some of these lists found that albumen, cyanotype, silver gelatin prints (among others) should not be used with buffered materials. If this is true, then perhaps the appropriate response to the OP is not to worry about the print but don't use buffered boards for mounting. I'm not a photographer nor a paper conservator but this surprised me and seems to beg the question -- is there a definitive position on the use of buffered materials with photo products? Note: I've ignored the overlap with lignin-free, acid free, neutral, neutralized, alkaline, etc for brevity.

In the meantime, a poster commented that baryta is a buffer between the paper and silver image and another poster commented that RC(polyethylene) prevented contact (presumably by the emulsion) with the paper base within the RC sandwich. The reference to buffer in these 2 cases appears to be as a barrier which is different than that in the OP. Actually, neither a baryta nor RC layer is a barrier to the movement of materials throughout the package. Some products have had materials added to the raw fiber base that were intended to migrate into and/or through the baryta or RC layer and in other cases pH adjustment in the raw base affected emulsion characteristics.

 

[Photo Engineer]

Yes, in the case of Baryta, the materials in the Baryta layer appear free to move into the emulsion layers just as emulsion chemicals can move into the Baryta and paper. I have tested this at coting time. After processing and washing though, it is not clear what is left to diffuse either way or how much is left of whatever was there to start with. The buffering ability of gelatin on Baryta is different than on RC. The pH will probably be different.

With RC papers, the buffering components of the emulsion are, for the most part, hydrophylic and don't like that RC barrier. Coming the other way, many organics in the RC do diffuse down into the paper and up into the emulsion, especially if they are even slightly hydrophylic. We detected some of the antioxidants in RC paper and resin in the emulsion after long term keeping, and in one case of an early antioxidant, we even saw some crystal formation on the surface of the print.

But, generally, the gelatin offers a slight buffer in a thin surface of a print. On RC, this is more effective than on the equivalent FB support. Whether it is enough or at the right value is another matter. As for the more esoteric papers, mount boards and etc... or for the more esoteric processes, who knows?

PE

 

[Donmck]

I am under the impression(not a chemist),that all wood pulp based paper will eventually turn acidic,
regardless of what type or how much (chemical) buffer is used.I am also under the impression that the reason they started using a baryta
coating ,is to (physically)buffer the emulsion from the paper after they changed from cotton rag/linen paper to wood pulp.

Oddly, when I googled Ilford baryta photo paper,up pops pages of the new baryta ink jet paper--(who knew) but I assume the usage is the same,although they don't actually say what the archival properties of the baryta coating are----so,who knows.




HARMAN Technology Limited, the pioneering Professional imaging specialists, have introduced the first professional Inkjet media products to use Baryta; an ingredient that has long been credited with providing traditional photographic prints with their high definition, wide tonal range and archival properties. Baryta is a coating that sits above the fibre base of the new Harman inkjet paper, lying underneath the regular active and protective coating layers. The Baryta layer prevents the emulsions from soaking into the fibre base, thus enhancing the detail of images. Added to this, the Baryta allows a much broader tonal range with greater detail in shadows and highlights. Harman is also manufacturing the new media using a heavy paper stock to help recreate the physical attributes of traditional photographic prints. This stock also helps to generate a robust and versatile print, which along with the archival properties of Baryta enhanced products, creates a print that preserves the value of the image.

http://www.jr.com/inkjet-photo-paper/pe/HAT_1149656/

 

[papermaker]

I am under the impression(not a chemist),that all wood pulp based paper will eventually turn acidic,
regardless of what type or how much (chemical) buffer is used.I am also under the impression that the reason they started using a baryta
coating ,is to (physically)buffer the emulsion from the paper after they changed from cotton rag/linen paper to wood pulp.


This is essentially correct, wood pulp based papers will eventually turn acidic. However, the time frame for well-made papers can be on the order of several hundred years. Wikipedia, under Acid-free papers, has a good description of this. The roll of buffered materials for packaging, storage, mounting, matting, etc, is to provide a material which has a reserve of alkalinity which can absorb acids whether there originally or as they form either through decomposition or from environmental factors.

However, this is not the reason for the original use of baryta coatings which started prior to 1900. The conversion from rag to wood pulp began in the mid-1920's and, for Kodak (the only one I'm qualified to speak on) was completed for most papers in the early 1930s.

You can find more about baryta and issues with conversion from rag to wood pulp at:

www.notesonphotographs.org

 

[Ray Rogers]

I think "...the reason they started using a baryta coating , is to (physically) buffer the emulsion from the paper after they changed from cotton rag/linen paper to wood pulp." is incorrect.

Most likely, it's first use was aesthetic, but of course uses may have overlapped.

Ray

 

[Photo Engineer]

Baryta was used, among other things, to give whiter whites and to reduce the interference of paper fibres in sharpness. Coatings on Baryta are sharper than coatings on bare paper. But, both have their own artistic beauty depending on subject matter.

PE

 

[Donmck]

---yeah,but what is the magical quality that makes baryta paper so archival?

Lots of interesting stuff in the link papermaker posted ,but I didn't find and answer to the archival question.(though I do understand there is difference between science and marketing)

One interesting blurb-


In 1968, the number of distinctive raw base papers had increased to 72 which were turned into 150 different baryta coated papers. The increase in number of papers since 1930 was due to new sensitized paper products being added, such as instrumentation, graphic arts, document copying, and industrial papers. In addition, the numbers also included color products that were still produced on baryta coated papers. In fact, the new papers mentioned above had outpaced in volume the more traditional fiber base B&W papers commonly used in what came to be known as the commercial and professional markets. In addition, the rapidly increasing demand for color products outpaced all of the products and the growth of resin coated papers for many products meant that by the early 1970s about 70% of the products were resin coated rather than baryta coated.

 

[Ray Rogers]

What's Knot

---yeah,but what is the magical quality that makes baryta paper so archival?

Perhaps it is not so much what is there as it is what's not.

 

[Photo Engineer]

Many prints made on non-baryta paper supports still exist from over 100 years ago. There is nothing magical about the life expectancy of a baryta paper over a non-barayta paper. The fact that more care has been given to photographic supports may extend this life, but any good book from the 1800s or so could have paper in it that could have been used for a photograph, as long as the wet strength was such that it survived the photographic process.

PE

 

[BetterSense]

What is the current MTBF of properly-processed RC papers compared to properly-processed FB papers? Everyone seems to agree that FB lasts longer but I'm looking for an answer like (50 years compared to 500 years).

 

[Ray Rogers]

MTBF?

Mean Time Before Failure?

 

[Ray Rogers]

I haven't seen recent data, and the data I do have is asleep right now, but... there are those who claim that gulf has been reduced or even that it doesn't exist anymore... at the same time, some have adopted the concept of "good enough is OK" and frankly, that bothers me. The message it sends is not one many artists want to hear.

 

[BetterSense]

Well, there IS such a thing as good enough...practically every step of the photographic process is a value judgment over what is "good enough". That's why having some actual data would be nice, so that everyone could make the "good enough" judgment an informed one.

 

[Anscojohn]

Years ago, when I did copy work and restoration, I told customers that I printed their repros on fiber-based papers, processed archivally. I told them we had the reasonable expectation the prints would last at least as long as the originals had hitherto--some of them were paper-based prints made as far back as the 1880s. I do not propose to wait around to see if RC (or inkjet) prints last that long!

 

[Ray Rogers]

There is a lot of interpretation involved in making those projections and idealy, they need to be backed up with real time tests as well... but even then how accurately they represent how the products will fare is IMHO kind of iffy... there are just too many variables to control for the average photgrapher... institutions have more hope. Anyway, the data is around, I think someone will find something and post it, if not I will look up the most recent data I have. There is probably recent data that I have not seen, at least from the last 10 years.

There is a new book on conservation that just came out if I recall, by a Frenchman who's name I can't spell. I haven't seen it yet.

 

[Ray Rogers]

Another problem I forgot to mention is that different manufacturers products are not similar enough for the results of experiments with one brand/formulation to be extended to others.

With the loss of so many manufacturers and products, my comment may already be less accurate, but for example, there was a difference between Kodak and Ilford RC papers with ID present IIRC, due to different formulations... I think Simon has stated here that ID is no longer present, I don't recall if that was for all Ilford papers or a select few, but on the otherhand, I have also heard that in some cases the amount was merely much reduced. With Kodak out of the paper game, and the passage of time, who knows what sort of lifespan
the current products being made will exhibit. That is why I suggest we look for the most recent data and not that from the 80's.

Ray

 

[dancqu]

But We Do Have "some actual data"

Well, there IS such a thing as good enough...practically
every step of the photographic process is a value judgment
over what is "good enough". That's why having some actual
data would be nice, so that everyone could make the "good
enough" judgment an informed one.

We don't have any data on whether or not a print looks
good. Only taste will decide that. But we do have empirical
data on whether or not a print has been processed for
great Life Expectancy.

Simple tests we can conduct in our own darkrooms can
confirm the achievement of certain established standards.
Meeting those standards is good enough. Dan

 

[papermaker]

The web site of the Image Permanence Institute (IPI) is worth a look for all things archival: www.imagepermanenceinstitute.org. Copied in here is their definition of archival found in a glossary at their web site: A term often used to imply that a material will be stable over time. The term has neither a recognized standard definition nor a quantifiable method for verification.

The earlier request for mean time before failure is a good example of one of the issues -- what is the failure -- image fading, dmin growth, support yellowing, loss of physical strength, cracking, silver mirroring, etc, etc. Any of these could occur at different times depending on test conditions. And a product made to the best standards of the day can have a premature death if not properly stored and handled.