Egg Tempera Forums

Go Back   Egg Tempera Forums > The Forums > The Forum for Tempera Painting Issues

The Forum for Tempera Painting Issues Sharing the knowledge and experience of fellow tempera painters.

Reply
 
Thread Tools Display Modes
  #11  
Old 07-01-17, 11:48 PM
arbrador arbrador is offline
Member
 
Join Date: Aug 2003
Location: USA
Posts: 57
Default Hardboard- correspondence with National Gallery Conservator

Here is my original message and their initial reply followed by a lengthy response from them to which I've interspersed my responses:

Hello!

Could you please tell me the name of a manufacturer who makes the most archival fiberboard panels suitable for egg tempera painting.

i need very large 4x8 sheets so it's not practical to purchase same from a company such as Ampersand.

Thank you very much,

Lora Arbrador

DCL
12/21/16

to me
Dear Ms. Arbrador:

The product you seek does not exist by the nature of its design and manufacture. Fiberboard, know as MDF in the industry is made of wood scraps pulverized, mixed with a resin and a catalyst and then rolled into sheets of various thicknesses to form a board. The adhesives which are used most often are made of urea-formaldehyde. Their stability may be predicted in multiple decades or more if the panels are treated well and exhibited in stable temperature and humidity environments. No manufacturer will indicate that the board they produce is more long lasting than others because the purpose of the boards are not focused on creating items that are meant to be viable for centuries. Selecting a material made in the commercial world for home building purposes cannot provide either assurance of extended longevity or a process that values long life. Manufacturers make these boards for construction work, inexpensive furniture and many temporary items. They don’t put effort into doing long-term study on the effect of age on their products.

Many artist gravitate toward the use of marine plywood or birch plywood to paint on solid support surfaces. Explore some of them because they provide better quality wood species, at least for the surface of the board and the adhesives are waterproof in the case of marine plywood. Marine plywood is meant to be used in adverse conditions.

A company called Art-Boards is a company that provides a variety of solid supports and may have an MDF product that you would find useful. But again, no assurance can be made to predict the natural lifespan of these types of products.

Thank you for your question.

The Conservation Division
National Gallery of Art

Date: Sunday, December 18, 2016 at 12:22 PM
To: DCL <DCL@NGA.GOV>
Subject: panel painting


arbrador@gmail.com
12/21/16

to DCL
Hello!
Thank you so much for your thoughtful reply.

I have been contacting hardboard manufacturers and many claim that they no longer use a formaldehyde product.

I am familiar with the birch plywood but these are made of several layers of veneer which are subject to separating and blistering.

I've been in touch with Ampersand and they claim to use a hardboard that is appropriate for artists' use. They seem to state that that they have had contact with the NGA Conservation Division who has advised them. I'm wondering who that might be because they seem to differ with what you are saying. They do not give out the information about who manufacturers their board stating it is a proprietary process.

They will sell me one sheet of 4' x 8' hardboard but it would cost $100 to buy and $200 to ship! I am planning a very large egg tempera painting and will use practically an entire sheet.

Thank goodness conservators like you are here to guide us artists ultimately saving future conservators time and effort in restoring our works many years to come.

Thank you so much,

Lora Arbrador
Reply With Quote
  #12  
Old 07-01-17, 11:49 PM
arbrador arbrador is offline
Member
 
Join Date: Aug 2003
Location: USA
Posts: 57
Default More on National Gallery Correspondence about Hardboard

Dear Ms. Arbrador: I believe I may have provided a confusing reply to a part of the question you raised. MDF and hardboard are two different types of engineered wood products. MDF is as I described, a “porridge” made of wood that is compressed and then given a resin impregnated paper covering. The covering allows woodworkers to provide a very smooth surface for paint application or related purposes. Hardboard, is a wood pulp and bark based product that is compressed with rollers and heat along with some oil to create thin sheets of engineered wood for a variety of applications.

My response:
I've spoken with two manufacturers of hardboard recently: Stimson out of Portland, OR and Eucatex who makes hardboard from Eucalyptus grande (species) tree farms in Brazil. From what I hear most manufacturers no longer use oil to temper their boards.
Stimson uses only Douglas Fir wood chips mixed with a slurry of wax and resins. The representative told me that bone meal and "natural glues" are used but only trace amounts are left and do not require reporting on the MDS sheet (Material Safety Data Sheet). He said that industry has shifted over past 10 years and gotten away from additives. Their product is formaldehyde free and carbon compliant.

The Eucatex company states that only the natural resin from the tree is used but a light coating of wax is applied to the smooth side of the panel. For this reason I am going to use the Stimson panels. I have also heard some anecdotal reports that Eucatex panels do not accept paint as readily as other panels. In our case that might relate to the adherence of traditional gesso. But this may be due to the wax coating which might be removed with denatured alcohol and a light sanding. I've also heard anecdotally that eucalyptus wood is naturally very oily so that may be another factor against using it.

Both companies said that they call their boards "tempered" due to the pressure and high heat processing- oil is no longer added as a tempering agent as was previously done.

I did not speak to other manufacturers because since I am on the West Coast shipping costs would be prohibitive to.

DCL Comment:
Ampersand claims to use a single species of wood and maintains strict quality controls by an outside manufacturer of the hardboard they use. We do not know the source of the hardboard they purchase and rework to create coated panels for paintings and related artwork. The conservator who advised Ampersand many years ago is since deceased. However, in discussions with Ampersand, he was assured that the quality of their hardboard was far and above the crude industrial grade material found at all big box hardware centers.

My response:
I find it very interesting that Ampersand may have been advised several years back when the hardboard industry was using a lot more additives. Both the companies I spoke with adhere to the standards of the American Hardboard Association. Ampersand claims that their hardboard is made from hardwood fibers so that would be an advantage but Douglas Fir, (used exclusively by Stimson), although technically a soft wood, is known as harder than most other softwoods such as pine. Doug fir is 4 on the scale of 1-5, the same hardness as many hard woods.

DCL Comment:
At the end of the day, the argument boils down to what sort of substrate to use. Wood is wood. In the end it hardly matters how it was produced to some extent. It will behave like all wood behaves. The only time that one might question the type of wood to be used is when a work of art is subject to environment stress such as being exhibited outdoors or in a similar hostile indoor environment. Then, a marine plywood that is meant for adverse weather conditions becomes important. Hardboards and MDF or regular plywood do not do well in outdoor weather conditions. If a adequate environment is maintained for paintings on wood substrates, they can last for an extended period of time. Panel paintings on wood supports have demonstrated this. However, wood, by its nature can crack over time as humidity and temperatures fluctuate.

My response:
This is an interesting point. I doubt that egg tempera artists would hang their paintings in the elements so I agree with your point that "wood is wood."

DCL Comment:
The conservation world has no data on the long-term stability of hardboard, MDF, plywood or marine plywood. It has not been in use for hundreds of years. Those skeptical about wood have been using aluminum, polyethylene, aluminum sandwiched panels that are not influenced by weather conditions. They glue canvas or paper to these supports or paint on them directly with a special primer preparation.

My response:
I'm wondering if there might be a process of accelerated aging as there is for testing the light fastness of pigments? ET artists are experimenting with other surfaces but for my purposes the surfaces you mentioned would be just as heavy as the 1/8" hardboard and would still need bracing at the 4 x 8' size I am attempting. Koo Schadler, egg tempera teacher and artist extraordinaire has experimented with aluminum and does not feel the gesso adheres sufficiently. And adding another variable such as canvas or paper is risky in my opinion with ET.

DCL Comment:
The segment of painters who use traditional egg tempera is small. Many of them are icon painters who use traditional hardwood boards to serve as supports for their work. You might explore that community to see what they recommend.

My comment:
I have indeed explored that route. Traditional icon painters always use planks of hardwood which works fine for small works but as we know from historical works, once you join planks of wood the seam is a very vulnerable point and often separates or shows in the painting. Plus elaborate cradling systems are used to join planks of wood. I think dimensional stability is a huge advantage of engineered wood products!

DCL Comment
Last, noting the size of what you intend to paint, I would be concerned with the support that needs to be constructed behind your nearly 4 x 8 foot panel. As you know, a sheet of hardboard is very flexible at the size you wish to use for your painting. A substantial cradle needs to be made provide the rigidity you need to assure that the board does not flex. I think your issue is more of an engineering problem rather than a support problem. You also have to consider the overall weight of your finished piece. Even, canvas on a well made strainer would weigh substantially if it were 4 feet by 8 feet. A wood substrate with a proper back support system could weigh a considerable amount, making it difficult to transport and require a well designed mounting system.

My response:
Yes, I totally agree. I have painted large before although not this large. I always brace my 1/8" hardboard with strips of 1 x 2" moulding glued on with clamps approximately every 16", using triangulation of course. My last piece was 54" x 48" and I was easily able to lift it but required help in hanging if for an exhibition. I doubt I'll be able to lift this one myself but that will not dissuade me.

Good luck with your project.

Thanks so so much for taking the time to answer my questions. I'm hoping that the more thought we put into our materials as artists the less work you'll need to do in restoration one day!

Lora Arbrador
Reply With Quote
  #13  
Old 08-01-17, 03:39 PM
Koo Schadler's Avatar
Koo Schadler Koo Schadler is offline
Tempera Painter
 
Join Date: Dec 2003
Location: Alstead, NH & Zirahuen, Mexico
Posts: 299
Default

Hi Lora,

I know it takes time to do research and communication, so thanks for looking into this subject. Here are a few thoughts on the latest round of comments.

1. In the first paragraph the conservator tries to clarify the difference between MDF and hardboard, but I believe she was more accurate in her first reply to you, and that her current terms are incorrect. Yes, MDF and hardboard are two types of engineered wood products - but MDF, as far as I know, is NOT generally faced with a resin impregnated paper. I think, in fact, she is referring to MDO (these acronyms do get confusing...) Here are the differences:

MDF = Medium Density Fiberboard. A FIBERBOARD made from a mix of wood fibers, synthetic resins, and a small bit of wax.

MDO = Medium Density Overlay. A PLYWOOD (thin veneers or "plies" of wood glued together), with a paper and resin impregnated overlay bonded to the face of the wood.

As she notes, the MDO surface is made for painting (MDO is commonly used by sign makers). MDO is generally considered a good product for artists (for example, Golden Paint, a company that does a lot of testing, recommends MDO for artists use). However, as the conservator notes, engineered wood products have not been extensively tested for longevity. Doesn't mean they are necessarily bad, just haven't been tested.

2. I think the conservator's description of hardboard isn't quite precise, since I do believe there are still hardboards (wood fibers pressed together under heat and pressure) made from 100% wood, bond together solely with heat, pressure and natural lignans (no added oils or resins), although admittedly this product is increasingly difficult to find. When a hardboard is strengthened by the addition of resins WITHIN the wood (not on top), then it is no longer called "tempered hardboard" but either MDF or HDF. Well, at least that was the terminology at one point. It is admittedly confusing since the industry is always changing and not consistent in terminology. For example, I find it a bit confusing that Eucatix and Simpson both call their boards "tempered" by heat and pressure alone, when for decades "tempered" meant the addition of something (either an oil coating on the exterior of the panel, or resins within the panel). So, sigh, I guess the definition of "tempered" has changed... Admittedly a muddle.

3. I tend to believe Ampersand uses high quality wood content in their panel - the claim is at the heart of their product, and it would be most dishonest, as well as incriminating, if they did otherwise. And I sympathize with Ampersand's reluctance to publicize their source, as artists and other companies might bypass Ampersand (for whom it was undoubtedly expensive and time consuming to develop their product) and go straight to the manufacturer. On the other hand, it's hard to verify the quality of Ampersand panels without knowing exactly how or where they are made. Still, I tend to trust their claim.

4. I get that "wood is wood" - to some extent that is true. On the other hand, I think an argument can be made that there are meaningful differences between (in order of preference): (1) a cheap ¼" MDF filled with phenolic resins and who-knows-what-else, produced overseas with no regulations (2) a Eucatex panel - well made, but your're correct that both the wax coating and natural oils in the wood could decrease adhesion of traditional gesso, (3) Ampersand's panels, made specifically for artists use, or (4) a ¾" Steel Rule Die Board (the most stable, consistent plywood available) covered with a fine linen, then gessoed. It's true that wood responds to humidity, and all wood products move to greater or lesser extents. Still, the last item has a much better shot at stability than the first.

(I understand that the last item is heavy and not relevant to your large project. I just want to make the point that for smaller work, a high quality plywood with linen is arguably a better option than a poorly made MDF panel - so it's perhaps an oversimplification to say "wood is wood".)

5. The conservator says that if "an adequate environment is maintained for painting on wood substrates, they can last for an extended period of time". The only long-term, adequate environment for a painting is the controlled humidity, temp and light of a museum (along with a few, exclusive home art collections that have environmental controls). Very few paintings live in stable environments. Moisture, specifically Relative Humidity (RH) is one of the greatest challenges to art, especially anything that is hygroscopic or attracts moisture (like the panels and gesso we paint on!). The museum standard for RH is 50%, +/- 3%. Keeping RH at 45 to 55% is acceptable, but even that lesser standard is completely unrealistic for most homes (particularly with central heating and air conditioning, which can change RH by 20% or more within an hour. The faster RH changes, the faster wood moves, the more detrimental such movement is to paint layers). I could tell several stories of well-made paintings damaged by sudden, unexpected changes in RH within a home environment.

If I am painting (so to speak!) a dire picture, well, in some ways it is. Artwork in general, but specifically egg tempera (with it's moisture loving support and ground, and thin brittle paint) is actually fairly vulnerable. Paint long enough and you'll probably see some of your work damaged or destroyed for various reasons outside your control (it may take a few decades, but that isn't much time given the expectation, realistic or not, that a fine art painting should last for generations). This is what keeps conservators in business. Some might say, but what about all the paintings that have survived from the Renaissance? In fact MANY more paintings from the past have been destroyed than are still in existence; and the ones still in existence have been for the most part conserved. So, why bother to make a painting durable since it will probably run into problems at some point? The answer is, you make a painting durable to give it its best chance. (That is, if durability is important to you. It's also fine to not care about durability, as long as you aren't selling work. If you sell poorly made work and it falls apart, you can be subject to damages, according to the implied warranty of "merchantability". The painter Odds Nerdrum's story is a famous example).

6. Finally, a slight clarification on my thoughts on ET on aluminum. I don't merely "feel" that gesso doesn't adhere well to aluminum, I've tested it! (Sorry, I don't mean to be annoyingly fussy, but there is a current tendency to prioritize feeling over fact, so I want to be clear that my conclusion is more than a hunch, there was actual testing involved). As you say, adding another variable such as fabric over aluminum complicates the structure, but I'm not sure how much more risky it is than fabric over wood, which has proven beneficial. If a good adhesive can be affirmed for attaching fabric to aluminum (such as BEVA in liquid form, perhaps - more testing needs to be done), than I think traditional gesso might adhere well to fabric on top of aluminum. I have a separate concern with aluminum; how a water-rich tempera paint behaves on top. It might behave okay, perhaps even very well, but the jury is still out, more testing needs to be done. Please chime in (specifics, please!) if any painters out there have worked with ET over aluminum!

So, does any of this help you with your grand project, Lora?! Not sure, but good for you for figuring out the best possible option relative to your circumstance, budget, etc. Really, all we can do as painters is our best, and hope for the best. The final step is to label the back of your painting with everything that went into its creation, so if problems ever occur and need attention, a conservator will have a better chance of knowing what to do.

Koo

Last edited by Koo Schadler; 08-01-17 at 03:44 PM.
Reply With Quote
  #14  
Old 08-01-17, 09:26 PM
Koo Schadler's Avatar
Koo Schadler Koo Schadler is offline
Tempera Painter
 
Join Date: Dec 2003
Location: Alstead, NH & Zirahuen, Mexico
Posts: 299
Default

Good point about the labeling! And you're not worried about putting alkyd paint over gesso on the back? And I assume by labeling you mean stating what surface you are using to paint on. And your cloth must be linen? Lora

Hi Lora,

1. Alkyd house paint can be applied over gesso on the back, no problem. I use a colored paint (to differentiate it from white gesso) and apply two coats, and along the edges of the panel too (being careful not to get any alkyd paint on the front of the panel while doing so; it would interfere with adhesion of tempera paint). A solvent based alkyd house paint is preferable to a water based, but either would work.

2. By labeling I mean describe everything - your support, ground, paint layers, and varnish (if applicable). Also the date of completion, and your signature (to affirm it is you, the artist, describing the contents of the painting). I have Avery labels that I made on the computer, ready to go, that I stick on the back and then coat with shellac, with a space for signing and dating the label.

3. No, the cloth need not be linen, although linen is an especially strong fabric. You could also use muslin or a cotton canvas. I'll paste a handout on the subject in the next post.

All good questions.

Koo

Last edited by Koo Schadler; 08-01-17 at 09:37 PM.
Reply With Quote
  #15  
Old 08-01-17, 09:36 PM
Koo Schadler's Avatar
Koo Schadler Koo Schadler is offline
Tempera Painter
 
Join Date: Dec 2003
Location: Alstead, NH & Zirahuen, Mexico
Posts: 299
Default

APPLYING CLOTH TO A PANEL BEFORE GESSOING

When you apply true gesso over a surface with grain – a solid wood panel or plywood – you should first cover the surface with cloth. Otherwise, over time the grain may telegraph through the gesso, which can lead eventually to hairline cracks in the panting. Cloth is also a good way to stabilize a panel, even one without any grain (such as hardboard).

MATERIALS
Rabbit Skin Glue (RSG) or Polyvinyl Acetate Glue (PVA)
Use good quality glue (pale in color; not rancid smelling when warmed).

Wood Panel (solid, plywood or fiberboard)
Solid wood panels must be well made and properly aged. If using plywood, use high quality, cabinet grade, birch plywood with an irregular number of plies, the more plies the better. Use ¼” thick for small panels; 3/8’ up to ½” for larger panels. Another very good plywood option is Shina plywood, used in woodblock printing, which is very fine-grained and stable.

Cloth
Use muslin, cotton or linen. For artists’ purposes, linen is the best choice. You can buy whichever cloth you prefer from either an art store or a fabric store. Consider the weave, which can range from fine to coarse. A fine weave is easier to fill in if you want a perfectly smooth gesso surface. Avoid cloth that has knots or bumps in. Wash in cold water and line dry before use. You do not need to iron the material after it has been washed.

You will also need: oven top, double boiler, water (distilled is preferred but not requisite), 1 ½” bristle brush, sand paper (around 220 grit), newspaper (wax paper is useful but not requisite), squeegee or wide plastic scraper, scissors, small wooden blocks (to raise panel above tabletop).

DAY ONE
If you opt to work with Rabbit Skin Glue, combine 1 part RSG to 20 parts water. Distilled water is preferred. Stir, then let soak 4 to 8 hours until glue absorbs water.

Cut panel to desired size. Sand the back, front and sides to smooth splinters and rough edges.

DAY TWO
Cover work surface with newspaper. Slightly elevate panel above work area by placing small wooden slats or blocks underneath it (otherwise panel will stick to work surface as it dries). You may put wax paper on wooden blocks to prevent panel from sticking to them.

If you opt for PVA, follow the instructions given below, substituting PVA for RSG. Omit the step of soaking cloth in glue beforehand, and do not put a final coat of PVA on top of the cloth (it would coat and possibly seal the porous surface of the cloth, which might interfere with gesso adhesion).

If you choose to work with RSG, first heat the water in the double boiler (DB). Remove DB from heat source; then put glue pot into DB bath. RSG should never sit directly on heat source. Warm RSG until it is fully dissolved (5 – 10 minutes). Brush glue on back, front and sides of panel until well coated. Place panel carefully on drying blocks so that the panel mostly doesn’t touch and can dry all around. Let dry minimum 4 hours or overnight. Store glue in refrigerator when not in use. When cooled it will harden into a gelatinous mass but will re-liquefy upon reheating.


DAY THREE
Cut cloth to desired size (either just slightly larger than panel or large enough to wrap all the way around to back of panel – for options on how to wrap cloth, see below).

Reheat RSG as described above, in double boiler off heat source. With a brush apply fresh layer of RSG to front of panel. Submerge cloth in heated RSG until cloth is fully saturated with glue. Lay cloth on top of panel. Line up weave parallel with sides of panel. Gently rub with fingers to remove air bubbles and flatten cloth; then use a plastic scraper or squeegee to fully flatten cloth – but don’t press too hard (or you will squeeze out too much glue). Be careful not to tear or distort the weave of the fabric. Leave extra cloth hanging over edges (don’t worry yet about laying cloth flat on sides of panel). Let dry overnight. Put glue in refrigerator when not in use.

DAY FOUR
Flip panel over. You can either
- cut the cloth flush to the edge of the panel’s front using a metal ruler and sharp mat knife, or
- wrap the cloth around the sides and/or back of the panel.

Warping Cloth Around
There are different ways to wrap the cloth around the panel - some involve cutting the edges and/or corners of the cloth, others not cutting the cloth (think of wrapping a present, or bed corners). There is not one correct way to do it; select whatever works best for you.

Reheat RSG as above, in double boiler off heat source. Flip the panel over so that the dry, front side (now covered with cloth) faces downward. Once again raise the panel off the tabletop on small blocks or slats, preferably covered with wax paper. Brush fresh RSG glue on the sides and back of panel, as well as on the unattached portions of the cloth, until everything is fully saturated with glue again. Wrap cloth around sides and back as desired. Press and smooth the cloth until all air bubbled are gone and cloth lies flat. Let dry overnight.

Once the panel has dried overnight, you can then reheat the glue once more, and coat the entire panel with another coat of RSG, although this is not requisite if you soaked the linen in RSG before applying. If you applied the linen with PVA, apply a layer of RSG over the linen on front.

Cloth covered panel is now ready for application of gesso.

Last edited by Koo Schadler; 08-01-17 at 09:40 PM.
Reply With Quote
  #16  
Old 15-01-17, 04:24 AM
arbrador arbrador is offline
Member
 
Join Date: Aug 2003
Location: USA
Posts: 57
Default Info on cloth layer

Thanks Koo! As always you are a wealth of information and so articulate and detailed in explaining everything. I'm excited to get the latest version of your book when it comes out. I still use my two older versions but each time there is so much new info.
You are a total treasure to all ET artists!!
Lora
Reply With Quote
  #17  
Old 15-01-17, 08:41 PM
Koo Schadler's Avatar
Koo Schadler Koo Schadler is offline
Tempera Painter
 
Join Date: Dec 2003
Location: Alstead, NH & Zirahuen, Mexico
Posts: 299
Default

Thanks, Lora. I sometimes fret that I am a bit too much of a presence on this forum, and want to assure others that my intent isn't to dominate the discussion - I'm just very interested in tempera, and have a lot to say! I'm always eager to hear other voices.

Although a few conservator, historians and painters specialize in tempera, compared to most other mediums it is little studied or understood. You, me, and others on this forum who love tempera and have worked with it for years can pool our knowledge to create a greater understanding and appreciation for the medium, which deserves a presence in the 21st century.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 11:40 AM.
Design modifications, graphics and CSS by RobM
June 2010



Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.