The Framers Forum

I've been asked to deal with a picture that's had a bad attack of mould. Mostly it's the mount that's been affected - a large patch in one corner which has black mould and also furry mould - no problem, the mount can be replaced. There's a little furry patch on the bottom of the print but again no problem - fortunately there's a lot of white space at the bottom of the image which can be cut off. The backing tape was a bit manky but the mould doesn't appear to have penetrated the wood.

However, I'm aware that there may be invisible spores in the wood* so should I treat it with some fungicide? If so, any recommendations?

Also, the print (which is printed on a glossy-faced card) feels a bit damp, and that too may have some invisible spores. Any idea how long I should leave it to dry out before re-framing it? And will drying it out kill any residual spores?


* The picture is one of a series of pictures so the customer doesn't want to have a new frame.


I would welcome your thoughts on this.

Consevrators can kill mould and mould spares with thymus, unfortunately thymus is also deadly to human beings and treatment with thymus requires particular equipment so this can be done without potenially leathal risk to the human operator. Such equipment is not available, even to many conservators, as a result it is not likely to be available to, or for that matter affordable for those of us who are primarily working as framers. So, if we are going to deal with this problem our selves, we have to follow a totally different approach, which does not necessarily kill any remaining mould spores, which we were unsucessful in removing, but does not allow them the conditions where they can grow at a later date. Obviously this is not a completely perfect solution as it only prevents the conditions for mould growth, while not killing the mould spores if any remain.

So, what conditions are necessary for mould growth? Mould prospers in humid conditions, an acid (not alkaline) environment and in the dark with little airflow. Mould is not killed by bleach, even though bleach kills almost all other life forms, including most bacteria, so don't bother cleaning the old glass and re-using it, even if you clean it with bleach. If you are re-using the original frame, it will be necessary to clean the frame on all internal and external surfaces back to as pristine a condition as possible. As I have already indicated, there is nothing that you can use which is going to kill any remaining mould spores, but most surface mould can be removed from the surface using a detergent and water.

I apply the deterent and water with a stiff 1/2 inch glue brush and at regular intervals, I wash the brush clean under a running tap and I soak up any remaining dampness with kitchen tissue and leave the frame in a warm, but not hot place to dry. After the frame has had more than adequate time to fully dry out, I apply one coat of dilute PVA, which I allow to fully dry and then follow that with one coat of full strength PVA. Depending on the formulation of the PVA and the degree of any later subjection to a damp atmosphere, we must anticipate the possibility the PVA may be even if it is to a limited extent potentially hydroscopic. Which means I don't regard the PVA as a perfectly waterproof medium, it's not bad, but if we are smart we don't make too many assumptions. So since I like a secondary barrier to be extre sure, I would line the internal surfaces of the rebate with Linco aluminium barrier tape.

The artwork needs to be examined before under taking any cheaning can commence, I'm sorry to say this, not everyone is going to be able to do this, or conduct any other procedures necessary to clean and conserve the artwork. You don't learn this stuff by just reading the right books it takes training, practice and exerience. As many of us will already know, practicing on a customer own artwork is a fast track to getting a upest customer and damaging your own reputation. Having said that the artwork needs to be examed to determine the artworks condition. Cleaning an artwork which is in a fragile condition is a risky business and may dictate actions to stabilise the condition of the artwork, so if you are out of your depth, it's a job for someone who has the necessary training, equipment and experience.

An experienced conservator will know how to clean and deacify the artwork and then then artwork can be mounted using an alkaline buffered conservation window mount, an alkaline buffered undermount and preferably a waterproof backing board and maybe a suitable imperious acid barrier between the backing board and the frames contents. Those who study the F.A.C.T.S. framing standards will understand that a layer off mount board does not according to them constitute an acid barrier in the longer term and in their standards is only defined as a filter. These days some of us are installing a sheet of mylar to provide a better long term barrier.

A cleaned and deacified artwork which has been restored to an alkaline condition, together with alkaline buffered window and under mounts in sealed enviroment will deny any surviving mould spores the conditions to grow. It is still necessary to mention that if the picture is going to be displayed anywhere in a damp environment then the whole sandwich to be framed needs to to sealed to prevent any possibility of entry of any moisure whatsoever.

Brilliant reply, Mark

Thanks for sharing that insight - very interesting.

I didn't know how indestructible those spores are....they sound like Japanese Knotweed!

I asked a similar question on another framers group a few months ago.
The almost consensus was that it was a job for a conservator, except the one person who insisted that Thymol was the way, but there was much head shaking towards his comment.
Another point made was to store the work in a sealed bag while in the workshop, to prevent the spores spreading to other works.
The general view was that if the piece was important enough to the customer, then they would pay for the conservator and that it was not in the remit/skillset of a framer to attempt to fix the mould issue.
Hope this helps.

There are mold spores all over the place. Trying to kill them is mostly futile.
They do no harm while dormant, they are waiting for the right conditions in which to thrive.
Trying to 'mold-proof' something with aggressive chemicals might do more harm than good.
The best way is to make sure the print is kept in a stable environment.

It's probably a good idea to open the other matching frames to inspect these and ensure that there is no hidden mould leracking inside any of those. If one has been affected with mould, it would be reasonable to assume that they're all come from the same place and the others may have faced the same conditions and environment.

Mark, thank you so much for taking the time to write that very detailed reply, and many thanks for the other replies which have each given a new perspective. They've all been very helpful