Wednesday, 29 April 2015

Day 13 and 14 Sidetracked by Vellum

I was sidetracked on day 13 and didn't paint or draw anything for the challenge! Instead I attended to a job that has been perplexing me since I returned home from London....the slight warping in my larger works on vellum! Although Kelmscott vellum sits reasonably flat at smaller sizes, when it's larger it can easily buckle and any exposure to humidity over time can cause this warping in small works too. Natural and manuscript vellum are thinner than Kelmscott and even more prone to warping. So on day 13 instead of painting I spent time trying to mount some pieces of vellum. For day 14,  I painted on the vellum.
On day 13 I mounted the natural vellum and day 14 I started this painting of a magnolia leaf skeleton but didn't have time to finish it.
Recently I've being doing some research for a new website I'm building which is all about vellum painting. I discovered that years ago miniatures were glued to playing cards to keep them flat, so I decided that it might not be too difficult to do it myself! I purchased rabbit skin glue and a variety of archival artist panels. Some are thin, about  1/8th inch and others are deep and cradled. I'd seen a few works on vellum at the Park Walk gallery last week, Carol Woodin's work was beautifully mounted on a deep panel whereas Kate Nessler's was not mounted. Both looked amazing but it's nice to have the option of presenting work in different ways and I want to be able to give my students the right recipe for mounting their work successfully if they wish. At the moment it's experimental but so far the results seem pretty encouraging.....but lets see how these first trials hold up over time.
The rabbit skin glue can be purchased in granules or sheets. The granules need to be soaked in water for about two hours, stir regularly to prevent it from solidifying at the bottom of the jar. I used an old jam jar. I used 20grams of glue: 250ml of water. The ratio of glue to water can be adjusted according to the job.
 I was expecting the glue to smell pretty bad but actually it has very little odour but you should be careful not to inhale any dust and to work in a well ventilated room.

I used an off--cut of natural vellum which was cut to be slightly larger than the 6 x 8 inch panel, I chose a panel with a primed slightly porous surface  I wanted it to be light behind the vellum to keep the brightness and I  needed the surface to absorb the glue in order to make a good bond, I could have applied the gesso coating myself  but decided to try a ready primed one first. This one is suitable for mounting canvas and other materials so it should be fine for velum too.

The glue should be heated to around 60 degrees, it should not be boiled. If the temperature rises above 70 degrees the bonding capacity is broken down. I placed the jar in a heavy bottomed saucepan which was filled with of water ( that's a double boiler or bain marie). I places a piece of folded cloth underneath the jar to ensure even heating. I placed a thermometer in the jar and stirred continually. I took about 15 minuted to dissolve all of  the granules. Never use a wooden spoon to stir if it has previously been used with any salt, this destroys the glue. 
After the glue had cooled for a few minutes I painted the panel with it. It has to be used warm and solidifies quite quickly ( but can be reheated a couple of times ). Once glued I positioned the vellum on top of the panel and smoothed it out. Tracing paper was over the vellum and heavy books on top of the panel. I checked it after 10 minutes and changed the tracing paper because it had rippled. I replaced the books and left it for 24hrs. I then trimmed the edges off the vellum, if it had been a little larger I could have folded it around the edges, this could then be float mounted. I'll try that once 've mastered this method.

Finally, I treat the vellum in the normal way by rubbing over it with a mix of 240 mesh pumice and French chalk, this removes any grease or marks.

The panel turned out very well, it's beautifully smooth and feels better to paint on. For day 14 I painted part of a a delicate magnolia leaf skeleton on the mounted vellum but will have to try something with more depth of colour to check that it doesn't lift. It certainly seems well secured, and rabbit skin glue is very tough! It's alos reversible so the vellum can be taken of f the support in need be. This whole process didn't take very long, maybe an hour and cost in the region of £7. This is only small panel though and with larger pieces it's definitely trickier. I have some larger ones currently being pressed and have also completed my first bevelled edge.  
I'm planning on painting 3 much larger magnolia leaves on vellum for next years SBA show so I'd like to make sure that the vellum is well prepared.... I'm starting early!


  1. i am now starting to get interested in vellum...... oye
    i wonder if it could be just edge mounted, and preserve the bounce of light behind the painting itself

    ('s me duck)

  2. Hi Duck, as well as this method it can be stretch on a frame, I've done that before once ages ago. Just like a canvas, drum or banjo skin! :) it looks nice float mounted