Digital BW, The Print

Encouraging news Paul.  Does spraying the back of the Epson photo paper 
remove the warping from heavy ink load?

Carl

On Thursday, March 25, 2004, at 08:09  PM, 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
>