Friday, June 22, 2012

The Importance of archival materials for art and framing

The Importance of Archival Materials:  Part 2
     by Susan Avis Murphy
      Do you know what can ruin your appreciation of an artwork after a few years?    Creeping decomposition…   I have been working in the art and framing business now for about 35 years, and I could tell you some horror stories!  In the last article in this series, I told you about the flowers that faded away completely during just two years in a painting a customer told me his mother once bought!  That was an issue of lightfastness of the pigments (link to article on lightfastness).   This article is going to be about the integrity of the materials the paint is put on and the framing materials that surround the painting.
     “Creeping decomposition” sounds creepy, doesn’t it?  Decay of a painting and its framing can start occurring immediately and become apparent in about five years.  What are the chief culprits and monsters of this decrepit situation?
·      Acid.  Acid found naturally in wood pulp materials, such as cheaper art papers and cheap matboard, will eventually cause those materials to become yellow and brittle.
·      Mold.  Mold present before framing can grow and spot the surfaces if the picture is stored in a humid environment.
·      Insects.  Tiny insects such as spider mites like to creep into narrow spaces and eventually stain the surface of the mat and picture.
·      Pollution.  Especially smoke, such as cigarette smoke will eventually dirty the surface of an exposed oil or acrylic painting
·      Dirt.  Dirt can somehow get under the glass of a painting—hard to believe but true!
·      Humidity.  Humidity is one of the main culprits and can cause warping and buckling of the painted surface and mat.
·      Heat and dryness.  Heat and excessive dryness can cause the glue to fail in the joints of the frame.  Ever see a frame whose corners are coming apart?  The glue has failed and hopefully the frame is hanging together by virtue of its joining hardware!
     Let’s take these monsters one at a time and see how they can be defeated!  In this article we will discuss acid, and in future articles we will tackle the other creeps!
·      Acid
o    Acid found naturally in wood pulp materials, such as cheaper art papers and cheap matboard, will eventually cause those materials to become yellow and brittle.  Works of art done on paper are very vulnerable to this if the paper is made of wood pulp, such as cheap drawing papers (newsprint used for practice, for example) and cheap watercolor paper.  Paintings and drawings done early in an artist’s career are often on these surfaces.  Not much can be done for these papers after the fact.  There is a product called “Archival Mist” that is sold, and purportedly can stop the effects of acid (it contains an alkaline buffer).  It is very expensive and I don’t know how well it works, but am doubtful.  The best paper for art is “rag” paper, made from 100% cotton (I suppose it used to be rags!).  This contains no acid and should last for hundreds of years under good conservation framing.  All the better and best drawing and watercolor papers are rag papers.  I use mostly Arches watercolor paper, which has a 400 year history and is extremely durable.
o    As for matboard, this is another problem in preserving the integrity of the artwork.  Cheap, “decorator” matboard is a hazard to your artwork because acid from the matboard can creep into the edge of the art.  These matboards are made from wood pulp that has been neutralized with a calcium carbonate buffer, but eventally the effect of the buffer wears off.  Better to use either “alpha cellulose” matboard or rag mat board.  Alpha cellulose mat board is made from virgin alpha cellulose wood pulp that has been chemically treated to remove all traces of acid and lignins.  Bainbridge Artcare® and Cresent Select® are two brands of alpha cellulose matboard.
o    Backing board can create even worse problems than matboard!  Plain cardboard or Masonite should never be placed behind an artwork permanently!  These materials are very acidic and acid will leach into the paper artwork, eventually discoloring it and making it so brittle it can crumble.  The best practice is to use acid-free foamcore board behind an artwork.
Here are some photographs of a painting we recently re-framed here at ARThouse.  I show you these as an example of the terrible damage acid can do to framing.  Luckily the painting was done on a decent piece of rag watercolor paper, so it remained intact, although was someone discolored.  The painting and framing was done in 1960.
Figure 1 shows the 50 year old watercolor with its original mat.  The glass was incredibly dirty and had been removed before this photo was taken.  The glass was a heavy window-type glass and had to be discarded.   Here you can see the yellowing and acid burn of the matboard.  The inside edges had turned dark brown (a sure sign of acidity).  The matboard was brittle and crumbling by this time.
Figure 1
 Figure 2  shows the back side with its paper dust cover and brown package tape crumbling away.  The tape flaked off, but the gray paper wasn’t too bad.  Today we would use an acid free backing paper so that it retains its integrity and is less likely to rip or puncture with time. 
Figure 2
 Figure 3  shows the corrugated cardboard backing board that had been used behind the artwork.  Wow, we certainly would never do this today!!  Corrugated cardboard is a terribly acidic material.  Today we would use an acid-free foam core board.  Probably some of the discoloration of the mat and painting was due to this cardboard.
Figure 3
  Figure 4  shows the painting as it is taped into the back of the mat.  Here we see a lot of “no-no’s”.  The painting has been taped all the way around, which is a bad idea because it does not allow for expansion and contraction of the paper artwork due to humidity changes.  It is a better practice to tape it only at the top.  Secondly the tape was extremely brittle and flaked off because, although plastic, it was not acid-free.  Today we would use either linen tape or an archival acid-free plastic framers tape.  
Figure 4
Figure 5 shows the back of the watercolor after it had been taken away from the acidic matboard.  The remaining tape is mainly just the glue part—the black plastic crumbled to dust…  Luckily the painting itself was still in pretty good shape. 
Figure 5
 Figure 6 shows the front of the painting.  You can see the acid burn from the matboard all around the edges.  The painting itself may have darkened with age and the colors may have changed.  It was not protected with UV glass, so the old pigments used in the 1960’s may have been vulnerable to fading or darkening if the color was not lightfast.  Standards in pigments have improved greatly, but artists still need to be careful to choose only lightfast colors. 
Figure 6

Figure 7 shows the final re-framed painting.  We cut a new double mat using Bainbridge Artcare alpha cellulose matboard and an acid-free foam core backing board.  Also, the frame was reused because it was a unique hand-made frame still in good condition.  However the corners were coming apart because the glue had failed after 50 years, so we re-glued it and joined it with v-nails.  It should now last for at least 100 years, I would say. 
Figure 7
      The painting has not been put under glass yet, but I would recommend Museum glass for this historical original artwork because it is valued by the owner.  Museum Glass® by TruVue is both a UV-protective glass and an anti-reflective glass, and would enhance the painting tremendously.
     The owner was extremely pleased with these improvements!  Thank you, Carl, for allowing me to show these pictures.
     I am pleased to help make you aware of these issues, and would be happy to answer any questions you have.  Please send me an email at  Meanwhile, here's hoping your paintings never undergo creeping decomposition!  And that your children and heirs will be always be able to enjoy the paintings you bought or created when you were younger...

      Susan Murphy, ARThouse, June 13, 2012 

      [article copyrighted, contact author for permission to reproduce]

Tuesday, June 12, 2012

What you don't know might hurt you!   
by Susan Avis Murphy
     Do you know what is one of the main things to think about when buying a work of art?    Longevity....

     By longevity, I mean the durability of the entire artwork over time.  Whether the pigments are lightfast, whether the support of canvas or paper is acid-free, and whether the framing is archival.  An original watercolor can remain fresh and safe for hundreds of years as long as these criteria are met.  A watercolor can last without damage as long or longer than most oil paintings if it is created and kept under the right conditions.  Let me explain.
     Standards in the art materials and framing industry have improved dramatically in the last 20 years.  Today's best pigments are thoroughly labeled as to their lightfastness (resistance to fading) and durability (resistance to other changes with time).  The best paint manufacturers, such as the English company Winsor & Newton, for example, carry lightfast pigments in most of their line.  But not all.  And that is where the problem can arise. 
     Some paints are not as lightfast as others.  For example, a very commonly used pigment in watercolor is Rose Madder Genuine.  This pigment, however, is considered somewhat "fugitive", ie it will "flee" or fade over time.   
     There is a national organization called the ASTM, or American Society for Testing and Materials.  The ASTM conducts lightfastness ratings for artist pigments, and Rose Madder Genuine only gets a rating of III.  Professional artists should only be using pigments with an ASTM rating or I or II.  For my own artwork, I only use totally permanent pigments. Also I always instruct my students to do the same and put a big emphasis on this...
     Take a look at this interesting little chart I created 20 years ago.  This is a segment of a much larger chart I made to test the lightfastness of all the pigments I currently owned.  Strips were painted, labeled, and then half covered with matboard and placed in a bright window for two years (about 3 hours sunlight daily).  Look what happened to Purple Lake, Rose Madder, and especially Scarlet Lake!  Can you believe it?!!  After this, I threw those tubes of paint away!
     Once I had a customer tell me about a painting his mother had bought, with red flowers in it.  After two years, the red flowers had disappeared!  Perhaps the artist had used Scarlet Lake!!
     Nowadays I continue to test my pigments just to be safe, and also as way to convince my students of the necessity to pay careful attention to the lightfastness of their pigments.  I have devised (and sell here at ARThouse) a special "Watercolor Test Sheet" that can be filled in with all the pigments an artist owns in order to determine their various properties, including lightfastness.  Here is what the sheet looks like before the artist has painted in the colors:

Watercolor Test Sheet -- unpainted
Here is an example of the sheet after the blues have been painted:
Watercolor Test Sheet with blues painted in
Here is one row of the sheet enlarged:

        Let me explain how the chart works.  Each pigment is used for one row, and painted on with water at a medium value.  The first circle is meant to show the general characteristics of the pigment, especially granularity (cobalt blue does not granulate very much).  The second circle is used to show the staining vs. lifting characteristics of the pigment: the circle is painted and then dried, and then the left half is covered with drafting tape while the right half is scrubbed off (using a stencil brush) with a fixed amount of water and pressure; this shows how easily the paint can be removed and whether it is a staining color.  The third circle is sprinkled with table salt while it is still wet, to show the degree of salt effect achievable.  The fourth circle contains a little black image so that we can see the degree of transparency vs. opacity of the paint.  And last but not least, the rectangle is used to test the lightfastness of the paint.  One half of this square is covered with dark paper and the sheet is hung in a bright window for about three months to two years.
Here is what the larger version looks like with colors painted in and black strips stapled over the rectangular square for the lightfastness test:
Large size Watercolor Test Sheet -- finished
       I have found these Watercolor Test Sheets to be extremely useful while I paint.  I use them mainly for choosing colors that I know will be liftable and not stain the paper, one of my main criteria for desirability of a watercolor pigment!  I also use them to remind myself of colors I seldom use.  And most importantly, I use them to ensure that my pigments are lightfast.  Any color that fades is banished from my palette forever!
       You can order a copy of my Watercolor Test Sheet from by going here: Watercolor Test Sheet
       There are several commonly used pigments that I would be wary of, if I were you.  In the Winsor & Newton line, be careful of Rose Madder Genuine and Alizarin Crimson, which get a "B" grade using the company's own rating system, equivalent to a III in ASTM terms.  These colors will change with time.  In the Holbein line, be wary of their four colors beginning with the words "Bright" or "Brilliant": Bright Violet, Bright Rose,  Brlliant Pink, and Brilliant Orange.  The company admits that these colors contain a flourescent dye, which glows upon exposure to light and makes the pigment look brighter.  The problem with this is that the flourescence involves a chemical reaction which decays over time, rendering the pigment much less bright than it was originally!
     As an artist or also an art collector, I would be very wary of collage materials whose sources are questionable.  For example, magazine paper used as collage, photographs, colored tissue paper, or rice papers from unreliable sources could all be extremely fugitive.  The colors you love in that painting when you buy it may not be there two years later!  Also many of these materials are not acid-free and will become brittle and decay with time.  Additionally, the glue used may yellow and suddenly show up like a sore thumb!  Ask the artist if they are confident in the longevity of their materials before buying.  I hate to say this, but hopefully it will make them more aware and more responsible...
     Is there anything you can do to preserve the artwork's colors if you are not sure about their lightfastness?  Yes, you can frame the picture under "UV glass" or Museum Glass (made by TruVue).  Visit the picture framing section of my website for a discussion of these types of glass: info about picture framing glass.  Museum Glass is a wonderful product, because not only will it protect the picture from ultraviolet radiation, but also this glass has an anti-reflective coating (an optical coating like the type put on lenses) that makes the glass seem almost invisible. 
     The bottom line is that artists need to be very careful about the pigments they use, and art buyers need to be careful that the artists they buy from are using lightfast paints!  Here I can say with absolute confidence that the pigments I have been using for the last 20 years are truly lightfast and will stand the test of time...  I thank my lucky stars that I can say this!
     For artists reading this, there is an excellent book on the subject, The Michael Wilcox Guide to the Finest Watercolor Paints by Michael Wilcox (latest version is around c2002).  Buy this book and consider it your Bible.  See the link in the sidebar at right to order this book from Amazon.
     One last comment.  Oil paintings are not necessarily more lightfast than watercolors.  Oil pigments can suffer from the same lightfastness problems, although the oil binder helps make them a little more resistant to fading.  The same is true for acrylics.
     I am pleased to help make you aware of this issue, and would be happy to answer any questions you have.  Please leave your comments here and I will gladly respond.  Meanwhile, here's hoping your paintings never flee!  And that your children and heirs will be always be able to enjoy the paintings you bought when you were younger...

Susan Murphy, ARThouse, June 11, 2012