Silver Point has been used for a very long time. Today, you can use a clutch pencil with a fine lead - of the order of 0.5mm - to draw fine, well positioned lines on various surfaces and with what today, we call pencil lead - a kiln-fired graphite and clay compound used for drawing - not undergoing development until the later part of the 15th century, metal point of some description was all there was to draw lines on paintings or even to produce drawings in their own right.
Silver, like gold, lead and copper is very soft and with a suitable, abrasive surface, dragging a metal point across it will leave small quantities of the metal behind. With the exception of gold, the others will oxidise and react with chemicals in the air. Lead leaves what is effectively lead white and so, in effect becomes very difficult to see, copper turns to malachite and when the silver reacts, it reacts with sulphide in the air to make sepia - the dark brown colour of older black and white photographs. All you need for the ground is something that is hard and abrasive enough to take the surface off the metalpoint - this is usually chalk but it can include marble flour or lead white. Personally, I would avoid using lead white in a ground - whether as the sole ingredient or as part of a mixture - because interaction with hydrogen sulphide is what makes silverpoint darken and lead white will react with that and darken as well.
The image on the right is of a lead 'plummet' used to draw an outline on a piece of quarter sawn oak covered with chalk in acacia gum.
Pure silver can be obtained reasonably easily - search online jewelry suppliers for bullion silver wire - and for drawing fine lines, wire with a width of 0.5 and 0.7mm are mounted in a clutch pencil. For doing broad shading, something wider is necessary and although a silver spoon might sound a good idea, they are made from sterling silver - pure silver is not strong enough on its own so sterling silver is only 92.5% by weight - the rest usually being copper. Bullion coins are 999 fine, that is to say 99.9% silver and you can pick up a troy ounce (31.1g) fairly cheaply - for example, a 1ozt silver Britannia has around £17 worth of metal in it but when you add an overhead for being a coin, VAT and postage, you can add £20 to that.
It clearly goes without saying that you should purchase your bullion metals from reputable sources - I once bought some 24ct gold leaf online through a general retailer which soon turned green with copper salts and since then, I have only gone to specialist gold/silver sites and with good results. In the UK, the Royal Mint is good because unless you are going to use a gratuitous quantity of silver, you only need to buy one or two coins over your entire career.
As an aside, when you go on the Royal Mint website (as already mentioned, a reputable source of bullion silver with regard to its purity) you might find the idea of buying into silver as an investment interesting. However, unlike gold, sliver attracts VAT (Value Added Tax) at 20 per cent and yet it talks about 'investing' in silver bullion. With a sixth of your investment being taken from the value of your purchase before you have even got your hands on the metal, it is clearly not an investment and the word 'Value' in VAT should really be replaced with the word 'Price' or 'Cost' because all it does is remove value from your purchase. If you are going to invest in bullion, go for a metal that doesn't get taxed. Throwing away a sixth of your investment means that you are going to have to wait for the spot price to increase by a fifth before you get the value of your tax 'investment' back, let alone make any money out of it.
The gold that you can buy for metal point from various art dealers has a lot of copper and other elements in it and is not pure by any stretch of the imagination - sometimes even as low as only 9ct (honestly advertised as 9ct). It also is quite pricey, especially when you compare it against the obvious alternative.
The world of the art shop is populated by customers who are going to wear away the metal over a long period of time and as long as it looks sort of like gold, all is well. This means that less scrupulous suppliers can pass off less expensive variants (14ct advertised as 22ct and so on) and make a bigger profit on them.
However, the world of jewelry suppliers is populated by customers who are going to use the materials that they purchase in artworks that are then going to send away to an assay office where they will be tested and anything that is substandard will be ritually destroyed. The jewelry supplier therefore has to supply what it advertises so if you buy 24ct gold, it has to be 24ct gold otherwise you are talking about police investigations and accusations of fraud from those who have received that gold ring that they spent weeks making being returned to them back from the assay office in a rather two-dimensional form.
I found that I could source pure gold wire (bullion gold - 24ct - 999 fine) from online jewelry suppliers. You can buy a couple of inches for not much more than the price of gold itself. The copper in the art shop gold wire will go green after a while whereas pure gold does not.
If you are going to buy a gold coin, I would suggest one of the smaller ones as gold is rather expensive with the current price being around £1,300 per troy ounce (as a comparison, silver is around £17 per troy ounce). If you are going to sell it, you might need to explain why half of it has been worn away ;-)
Gold does not produce as dark a line as silver but it does not change with time. Another artefact with gold is that when it is on the ground, looking at light reflected in its mirror surface shows that it is actually gold - unlike silver which, although it starts off as silver, eventually turns black then dark brown, gold retains its colour.
You can see in the image on the right that the silver wire in the clutch pencils performs like pencil leads but rubbing the coin on the surface produces a gentle shading.
When you first buy the silver wire, it will have simply been cut, with either shears or scissors, which can leave irregular ends with odd angles, burrs that can cut into your ground and so on.
On the right is a 1,000 grit diamond grinding 'stone' that will very quickly take off any irregularities but remember to bevel the sides of the end because 1,000 grit will make it sharp. Instead of using diamonds, you can use a spare bit of paper with the ground on it but it takes a while to get it just right. In normal use, you will tend to wear flats on them anyway but the initial irregularities need removing the first time.
In addition, you also need to fix the abrasive to the support and this can be dependent upon the support used - specifically how flexible the support was. On the right, you can see metal point - lead, in this case - used to mark out the lines for a painting on oak panel using acacia gum as the glue - this, I have already covered here. Silver point was used by Jan Van Eyck in the painting 'Saint Barbara of Nicodema' which was on oak panel. Here, I'll go through the options with using paper as the support.
Oak is sufficiently stiff to be able to use acacia gum as the glue. However, using that on paper might cause problems with cracking, de-lamination and so on, so something more flexible is needed. Animal glue - gelatin - is flexible enough and that is what we'll be using here. You can either buy so-called 'rabbit skin glue' or you can buy gelatin that is intended for cooking.
First, the paper. We need something that is stiff enough and strong enough and also, preferably not have a Fluorescent Brightening Agent (FBA) or, more commonly nowadays, Optical Brightning Agents (OBA) in them as these are all recent developments and if you want to make something that looks authentic, it is something to avoid. Cellulose, which is in cotton and wood, naturally has a slight yellow colour and this is because it absorbs light at the blue end of the spectrum. We don't see ultraviolet light so we can use chemicals that absorb the UV and then re-emit it at blue wavelengths, ie fluoresce. Get the right amounts and the paper looks white in normal light. If you look at it in UV light, it will fluoresce blue. Finding heavy, FBA-free, acid-free, cotton papers is fairly difficult but there is one that I found that is a reasonable price and is reasonably available: Fabriano Artistico watercolour paper and this is the paper that I use for all paper-based non-paper-tests that I have done on this site.
The paper is 300gsm, 100% cotton and so is nice and thick and strong. It is also externally and internally sized so I don't need to pre-treat it.
However, around half the sheets do have a great big advert running across it in the form of a watermark which, because of the way that watermarks are made and the fact that we are going to coat all of the sheet with a uniform layer rather than paint bits of it, it would mess up the picture. Cutting that off shrinks the sheet by 30mm or so.
Silverpoint artworks by Van Eyck, Da Vinci and so on are fairly small - 130mm x 180mm is about the size the tend to be. The watercolour paper is a lot bigger than that so now, you have a choice - cut the paper down to around finished size before we coat it or after. The choice is yours.
Making the Ground
There are a number of ingredients for grounds - ideally, you want something that is fairly light and neutral. Some examples are: marble dust; chalk; lead white; and, if you want more modern materials, you can use titanium dioxide and zinc oxide powders. We are going to try two here: a 2:1 mixture of chalk and marble dust; and, chalk on its own. The gelatin is, for the sake of convenience leaf gelatin which comes in 8 sheet packs weighing 13g. and the claim on the pack is that 4 leaves will gel a pint of water so one sheet in 70mls of water should be enough.
Weigh into the porringer 760g of water and heat up above the water - doesn't take long. Next, add the Gelatin and stir it in. It can take a while for it to disperse/dissolve (depending upon who you talk to about whether gelatin actually dissolves or not - we just need it to form a uniform liquid. Then, if you are using rabbit skin glue, you need to filter it through muslin. Finally, add the powder(s) and stir to disperse them which doesn't take long at all.
Mix the ground mixture well and dip in the brush. Use quick strokes in a horizontal pattern to produce an even coat. Let this dry out and then apply a second coat vertically. If you are going to apply further coats, keep on alternating the direction like this but make sire that the paper dries out properly in between applications. If you get a brush hair on the paper, pick it out using the end of the brush.
Finally, leave it somewhere horizontal to dry.
Marble Dust Paper
This is the ground with marble dust. You can see that there are some larger bits of grit in there but it is quite abrasive and will take silver quite well.
This is with two applied layers.
Here, you can see how well it takes the silver with the 0.5mm wire, 0.7mm wire and the bullion coin.
You can get an idea from the size of the tip of the wires what the scale of the markings is like and this might be a bit too coarse for some situations.
Acacia Gum size
As was said right at the very beginning, acacia gum is all right for solid surfaces such as quarter sawn oak but for paper, it is a bit too brittle.
Here, we use the recipe above and as an experiment, I coated a piece of paper one side with a single coat and the other side with three coats.
This is the chalk based metalpoint paper with silver on it and you can see that it holds the metal well.
This is some artwork for a book. It is silver point on chalk ground in the style of those odd machines that Leonardo Da Vinci used to draw.
This is a close-up. You can see how
the silverpoint can produce sharp lines. Note that traditionally, halftones in silverpoint have been don in the manner of an engraving where you produce shading by using parallel lines that can vary in thickness.
Here it is finally, in the form of a book cover with the title and other information added using an image processor.
You can get a copy the book from Amazon by clicking here.
Silverpoint does eventually react with the sulphur in the air to turn into sepia which is a dark brown.
All images and original artwork Copyright ©2019 - 2020 Paul Alan Grosse.