On Thursday, March 25, 2004, at 08:25 PM, hogarth wrote: > I've got to ask. Might be a stupid question. What is the point of > buying > a paper that requires this kind of post printing treatment? I don't > want > to be in the paper manufacturing game, I just want to buy and use good > papers. So... why not buy a good archival paper to start with? The "archival" glossy and semigloss papers are relatively expensive and suffer from bronzing and gloss differential artifacts. > What am I > missing here? Beautiful glossy/semigloss prints with high dmax, low price, and in the case of Epson photo paper no bronzing artifacts. > > > > On Thu, 2004-03-25 at 20:09, Paul Roark wrote: > >> Short version: >> >> >> >> We may be able to make any glossy paper - also known as RC or >> "barrier" >> papers - "acid free" and perhaps archival by spraying the back with >> Wei T'o >> deacidification spray. (See http://www.weito.com/intro.htm) >> >> >> >> Long version: >> >> >> >> The Epson premium glossy papers are rated by Wilhelm as having a dark >> storage life of ">200" years, just like the best cotton papers. Most >> glossy papers are not rated so highly. When I test the Epson premium >> papers >> for acidity with my Abbey acid test pen, the difference I see is that >> the >> interior fibers are alkaline - buffered paper. The interior papers >> of all >> other glossy papers I've tested are acidic - not buffered. It is >> typically >> the acids from lignin that limit paper life. That is why EEM is not >> rated >> very highly - the paper doesn't last as long as the image. >> >> >> >> It appears that the Wei T'o deacidification spray penetrates the back >> side >> of these papers and buffers the interior fibers, but is stopped by >> the resin >> (polyethylene) barrier from reaching the surface. >> >> >> >> One of the problems with the deacidification sprays is balancing the >> goal of >> buffering the paper fibers with the conflicting desire to not touch >> the >> surface of the print and pigments. The buffers may lessen the dmax >> and >> might cause the image to yellow faster with light exposure. >> >> >> >> One type of deacidification spray (Bookkeeper by Preservation >> Technologies) >> does not penetrate paper at all. If the paper is sprayed on the >> back, this >> protects the image, but it also does not get the buffer into the >> paper where >> the lignin acid source is. (Bookkeeper just puts little magnesium >> oxide >> particles on the back of the paper as if they were pigments.) The >> theory of >> Bookkeeper is that acids migrate enough to be mopped up by buffers >> that are >> close. However, in my tests on EEM the interior papers never did stop >> testing as acidic. >> >> >> >> Another type of deacidification spray - Wei T'o - has the buffer >> (magnesium >> carbonate) dissolved in a solvent. With this spray the buffer is >> pulled >> into the paper by the solvent (alcohol and some others), where it can >> be >> more effective. Wei T'o makes different versions of the spray with >> different solvents that carry the buffer differing distances into the >> paper. >> I have #12, which carries the buffer into the thickest papers. >> >> >> >> The problem with this approach on matte papers is that the solvent >> carries >> the buffer right up into the inkjet coating and image. In fade >> testing I >> detected more yellowing in the test strip sprayed with Wei T'o than >> in a >> control test strip. The principal of Wei T'o has also warned that the >> coatings could be complex systems where the effects of the buffer >> might be >> unpredictable. We probably just do not want the buffer to get into >> the >> coating and image. >> >> >> >> So, what about glossy, "barrier" papers? Will the Wei T'o penetrate >> the >> back of the paper but be stopped by the RC barrier? >> >> >> >> It appears that many if not most inkjet RC papers have the resin - >> polyethylene - just between the coating and the paper base - unlike >> photographic RC papers that have polyethylene on both sides of the >> paper. I >> noticed with the roll of Glossy Paper Heavyweight I was testing that >> a spray >> of water on the back would take the curl out of it. This would not >> happen >> if the back were polyethylene. Since the barrier is to stop the >> water in >> the ink from reaching the paper base, and these prints are not >> processed in >> a tray of water like photographic RC papers, it does make sense that >> only >> one side would need a barrier. >> >> >> >> I have now tried the Wei T'o spray on the backs of several glossy >> papers, >> including Epson Glossy Photo paper and Ilford Galerie Smooth Pearl. >> These >> are two of my favorite cheap glossy papers, but they have acidic paper >> interiors that will limit their lives. >> >> >> >> The Wei T'o does penetrate the backs of the glossy papers I've tried. >> With >> the 2 papers above, the interior fibers tested as very alkaline after >> spraying, just like the Epson Premium glossy papers. >> >> >> >> But, with the Epson Glossy Photo Paper, I could not tell if the Wei >> T'o had >> also penetrated the barrier and polluted the surface. This is >> because the >> Glossy Photo paper has an alkaline surface to start with. >> >> >> >> The Ilford Pearl, however, like the Epson Premium papers, has an >> acidic >> surface. (This correlates with a higher dmax.) So, if the Wei T'o >> penetrated the barrier, it would turn the surface alkaline - It did >> not. >> Thus, the Ilford paper may have been effectively buffered without the >> coating and image being affected because the polyethylene barrier >> kept the >> Wei T'o in the paper and away from the coating. >> >> >> >> In short, the Wei T'o spray may make the cheap and good looking glossy >> papers acid free. This could extend their lives very significantly >> (many >> times). I'll have to fade test some samples as soon as my current >> test is >> over (which will be more than a month from now). >> >> >> >> This could be rather significant - cheap, acid-free glossy paper. >> The >> Epson Glossy Photo paper is even bronzing free. Now if we could just >> find a >> thicker version of that . >> >> >> >> Paul >> >> www.PaulRoark.com <http://www.paulroark.com/>
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Re: [Digital BW] Acid-free glossy paper
2004-03-26 by Carl Schofield