Get The Gas Out

During the 2002 Olympics, held here in Salt Lake City, Utah, I was privileged to have an exhibit of my landscape photographs.  I made the requisite prints on my Epson 2200 printer utilizing Epson papers and Ultra Chrome Inks.  For consistency sake I kept the image size the same and in either horizontal or vertical orientation.  Therefore I cut the entire group of over mats, assembled all of the frames and prepared all of the glass before making the prints.  Printing required two full days and then the units were quickly assembled and delivered to the location.

After the exhibit was over I removed the prints from the frames for storage.  I noticed a devastating fog on the inside of the glass of every unit.  I immediately began my queries as to what had happened.  That is when I found out you have to “get the gas out”.

I have found out that out-gassing fog is NOT an Epson specific problem.  It is an inkjet problem, regardless of printer, paper or ink manufacturer.  The out-gassing fog originates with the glycol wetting agent, which is used as one of the liquefiers along with the water and coloring agent in the inks (and pigments).

Most of the current crop of inkjet papers has either a RC (resin coating) barrier layer (usually polyethylene like traditional photographic papers) between the inkjet receptive coating and the paper base or an ink receiving coating over the paper base.  The denser RC barrier creates the bigger problem in gas trapping.  The barrier is used to prevent heavy ink loads from wicking into the paper, thus lowering image resolution, contrast and color saturation.  It also impedes excess moisture from reaching the paper base, which causes paper "cockling" (deforming wrinkles).  However, this same barrier can prevent the ink from drying quickly.  Although the paper may appear to be dry (and is dry to the touch, especially "fast-drying" micro-porous papers like Epson's "Premium" line), there are still plenty of liquid agents trapped under the super-absorbent ink receptor coating, lying against the barrier layer.

It is the trapped glycol and other ink liquids in and under the barrier layer, that may eventually out-gas (evaporate) and condensate (fog) on the inside of the glass, if a print is framed before it has had a chance to sufficiently dry.  Some have noticed that the fog on the glass is "oily" to the touch.  This is from the glycol.

People in the inkjet signage industry have long ago noticed that they must let their RC type photo papers dry for several days before they can heat laminate these papers.  If heat laminated too soon the trapped water and glycol will immediately turn to steam and create bubbles between the laminate and the paper.  The premium (heavy or thick) papers may require up to two weeks to thoroughly dry

Accelerated drying procedures may be needed when framing "Premium" papers (and all other RC type papers) behind glass to avoid out-gassing fog on the glass.  Epson and other companies suggest waiting at least two weeks before framing barrier type photo inkjet papers behind glass or laminating.  Unfortunately, most of us do not have that much time to wait.

Greg McCoy, a representative from Epson, suggests for those needing a quicker drying solution 'cure' the new print with a plain piece of paper in contact with the print for at least twenty-four hours.  After twenty-four to forty-eight hours, you should notice the plain sheet of paper is wavy, indicating that it has absorbed the moisture from the inkjet print.  The absorption receiver sheet may now be discarded and the prints framed, laminated or boxed and stored.

Epson’s Velvet Fine Art paper and other fine matte papers have a very delicate surface, which should be protected with a paper slip-sheet when being transported, boxed and stored.  Since there is a need for paper drying sheets and storage slip-sheets, how do we do this economically?  I found a good quality bleached white Kraft paper roll for around $40.00 at my local paper supply store.  This 24” wide, 1300 foot long roll provides about 600 24”x24” sheets for approximately seven cents a sheet.  I find this a reasonable cost solution.

Another note for storing your inkjet prints is that they should NOT be mixed with traditional photographic prints.  The by-products given off by the different media (black & white, color and inkjet prints) should not be mixed for their best longevity.  It is not overly expensive to utilize a different storage box for each type of print.  You can order your archival storage boxes here:

www.pictureline.com/photographic/storage/slightimpressions/lightimpressions.html

Epson's new pigmented UltraChrome inks nor any of their other ink sets seem to have glycol drying issues on matte and fine art papers.  There does not seem to be any drying problems with their cast coated glossy photo papers, such as the Epson Photo Paper (now called "Glossy Photo Paper") and their Glossy Paper Photo Weight (also called "Professional Glossy Paper") in sheet sizes.

I hope that your framing and storage problems will be prevented from what I have found in my misadventure.  Enjoy your photography and may your prints last. 

Submitted by askRodger@pictureline.com