Digital BW, The Print

George,


> <paul.roark@v...> wrote:

>> I like the looks of a sprayed Ilford Galerie Smooth Pearl even better --
>> great dmax.  However, it is a 30 year paper, probably due to its acidity.

>> A spray on the back with Wei T'o will make it "acid free," but I'm not 
>>sure how long it will stay that way.
> 

>None of the art stores around here sell Premier PrintShield. 
>Is there a source online?

See http://www.premierimagingproducts.com/dealerinfo/


>Also, what is Wei T'o. I haven't heard of this before.

It's a magnesium-based buffer that is dissolved in a solvent and put into an
aerosol can.  When it is sprayed onto a paper the solvent carries the buffer
into the paper, leaving it behind as the solvent evaporates.  This puts the
buffer where it is needed -- right into the paper.  The buffer mops up the
acids made by the breakdown of lignin, which is the main problem with
wood-based papers.

See http://www.weito.com/ 


Lignin (the acid reserve) is not in cotton, which is why the best papers are
made from cotton or some other fiber that is lignin free.  The problem with
even buffered wood-based papers is that even if they test as "acid free" now
(that is, the buffer is now mopping up the acids), we often don't know
whether there is enough buffer to continue to mop up the acids for however
long we want the paper to last.  Less than 1% lignin and more than 2%
calcium carbonate buffer is sometimes said to be the standard for "archival"
wood-based paper, but finding those numbers has not been very easy with
inkjet papers.  

Also, lignin itself, even if buffered, is photosensitive and will yellow the
paper in proportion to how much is there.  Lignin, which is what makes trees
stiff enough to grow tall, is one of the main ingredients of the biosphere
and probably can never be 100% removed from wood-based paper.

> You say to spray it [Wei T'o] the back of the print?

What I've found is that "glossy" or "barrier" papers made for inkjets have
only one polyethylene barrier, and that is between the coating and the
paper.  It's there to stop the water in the ink from getting to the paper
and causing it to get wavy.  Fortunately, the barrier also stops the Wei T'o
solution from getting to the image.  My tests of Wei T'o on non-barrier
(matte) papers suggests that the solution will yellow the image.

>On the glossy papers, even the Ilform pearl, do you the photo black ink 
>exclusively (talking C84,EZ).

Yes, for glossy papers you need the Photo K.  Actually the OEM black is a
hybrid that is not bad for short term snapshots -- on glossy or matte paper.
Don't use Eboni, however, on glossy papers.

Good luck.

Paul
www.PaulRoark.com