You are here:

Picture Framing and Art Preservation/sandwiching botanical between glass


QUESTION: I have a large fern frond; dried and pressed flat; then hand painted with acrylic artist paint and sealed with Krylon matte finish spray.

I am mounting the frond in between two pieces of museum glass so u can see beauty of both sides of fern. Will condensation between glass be an issue if fern is sandwiched in-between, directly touching both pieces of glass?

If so, how do I mount the fern in place between the glass so as to compensate for this?

If this is not an issue. How do I seal around the outside  edges of glass to seal the glass panes together for framing?

This is a special sentimental piece and would like it preserved for longevity.

Framed glass size 7 1/2 X 25 1/2 inches
with tall frond encased within glass

ANSWER: Hi Shelly,

Yes, I would be concerned about placing the frond directly in contact with the glass. As temperature and humidity fluctuate in the environment moisture will condense on the glass, and the problem is doubled with two lites of glass in contact with the art. One possible solution would be to use acrylic instead of glass, as it is a much better insulator and condensation is not nearly as much of an issue as it would be with glass. Since you are using Museum Glass the equivalent would be Optium. Of course it is much higher in cost so budget might be an issue. A second consideration is the fact that the acrylic glazing and acrylic paint, being chemically similar, might bond to each other.

I would suggest mounting the frond to the rear lite of glass or acrylic with dots of thick, freshly-cooked rice paste starch. Just use a number of small dots on places where the frond touches the glazing. Granted, it does involve using adhesive on the artwork but it is chemically stable, made of the same material as the frond (starch and water) and is easily and completely reversible.

Space the glazing apart enough so that the frond has room without the glazing pressing against it. FrameTek ( has a spacer made for exactly this type of application, FS 1/4" Double, that will hold the two lites apart with 1/4" space.

I hope this is helpful, and it sounds like it will be a lovely piece when it's done.

---------- FOLLOW-UP ----------

QUESTION: this is very helpful..also id like to know how to seal the outside edge of glass panes to keep out pollutants..dust etc...what kind of sealant will work well with museum glass as a long term sealant?..

If you are looking to create an absolutely airtight seal, you should probably leave that idea on the table. Such a sealed package is the type of thing that is done at institutions at the level of the National Gallery of Art, and then only in very specific cases for very specific reasons.

On a practical level though you can achieve a seal that will keep out insects and dust quite well simply using self-adhesive tape. Apply it to the front edge of the glass about 1/8" in, wrap it around the edge and to the backing (which in this case would be another lite of glass)and burnish well. For the project you have in mind Lineco's frame sealing tape would work very well. The adhesive is quite strong and the layer of aluminum will serve as a very good barrier against insects.  

Picture Framing and Art Preservation

All Answers

Answers by Expert:

Ask Experts


David Lantrip, MCPF, GCF


I can answer questions about all aspects of framing, with special emphasis on preservation framing. Categories of artwork include works of art on paper, needlework, textiles, paintings on canvas and three-dimensional objects. Components of framing includes frames, glass/glazing, mats, mounting, their features and how to select them.


I have been a professional picture framer and educator in the field since 1994, including framing education for a major franchisor encompassing three brands and the Professional Picture Framers Association, and writing and teaching for DECOR Magazine.

Professional Picture Framers Association (PPFA) > Board member, PPFA > Member, Certification Board > Member, Chapter relations Committee National Society, Sons of the American Revolution (NSSAR)

DECOR Magazine, 2005 - 2010 PPFA For Members Only newsletter Member of the PPFA Guidelines task force, assisted in writing PPFA Guidelines for Framing Works of Art on Paper and PPFA Guidelines for Framing Works of Art on Canvas, and PPFA Guidelines for Framing Textiles and Needlework. Picture Framing Magazine, 2012

Georgia State University, many classes as a student and educator through the Professional Picture Framers Association and DECOR Magazine. Current member of the PPFA guidelines task force and certification board.

Awards and Honors
Earned Certified Picture Framer (CPF) designation in 1996, Master Certified Picture Framer (MCPF) designation in 2004 and Guild Commended Framer (GCF) status in 2008.

©2017 All rights reserved.