Wednesday, 15 June 2011

A photographic aid for setting stones in sheet silver

Over the last few days I have been setting some awkward shaped faceted stones, well pear mostly and I have been using sheet silver to set them.  If like me you find it hard to get the cut-out in the back-plate to accommodate the stone exactly right, this might help.

Take your stone and turn it face down on a piece of black card or cloth next to the piece of silver you are going to be using and take a photo with your digital camera. Download the image to your computer and open it in your image editing software. Using the select tool select just the stone, copy it and then paste it into a new layer. Superimpose this new image of the stone over the piece of silver and position it as you want the final place to be. Make a new layer and paste the stone again so it sits directly on top of the stone in place, while it is still selected paint over it in black or some other colour to allow you to see the it. Now using the scale facility reduce this solid coloured layer so it sits comfortably over the stone showing the edges of the stone all the way round, so you know that when you cut the hole the stone will sit in the correct place.

Flatten the image and crop it so that the whole image is exactly the size of the silver you will be using, measure your actual piece of silver top to bottom or side to side and then print this image using the vertical measurement or the horizontal one. The resulting image will be exactly the size of your silver and the stone and the hole you want to cut. Cut out the image with scissors lay it on your silver and stick it with tape so it fits exactly. Make your punch mark drill and cut out the solid coloured part and your stone will be in the right place with the correct size of hole.

The same method can be used for using up scrap, follow all the steps, but instead of reducing the stone image enlarge it, and fit this enlarged image over the image of your scrap so you have a nice clean template for cutting out shapes in your scrap silver which you know will fit the stone you have in mind.


The following is an illustrated guide to the above method including the use of scrap for a specific stone. For the purposes of this "how to" I am going to use this rutilated quartz which although is square it has a deep table to culet profile and this sometimes makes setting difficult.

All pictures will enlarge if clicked on for a better view.

Rutilated quartz of 10.11ct 15.3mm by 11mm by 7.6mm

So as this is a two in one kind of deal, start by taking some scrap silver and melting it down and cast it into an ingot mould or cuttlefish bone or as I am doing here, for those who have neither of those things using an old soldering block which has a dip in it.
Scrap silver, borax powder in the dip of an old soldering block
Melted scrap

Scrap nugget of silver 


Cleaned up ready for hammering out


Once at this stage, pickle it to get rid of the crap and then hammer this nugget out on a steel block, annealing frequently until you have the desired thickness.


Hammered out

Pickle and clean up, and give it a rub over with sandpaper or micromesh, though this is not important at this stage as you will be polishing up properly later, I do it now as it just gives a kind of half way sense of achievement :0)



Rough sheet ready 

So now you have a piece of irregular sheet from which we can cut a nice back-plate for the stone.

Now of course you could measure this all up and scribe lines in the normal way to maximise the use of this small piece of silver, but I find as it is so slippery the ruler tends to move as does the set square blah blah so this is where the photo method comes in very handy.

As described in the text above, lay your piece of silver and your stone face down on a black background or any solid colour, this makes the selection process a lot easier.

Silver and stone side by side on black background
Open this image in your image editing software, I am using Photoshop Elements, but this will work in any programme which supports selections, the copying of selections, colouring and scaling. ( I tried it out on GIMP this morning and it is fine in that programme and it is free).


Now using the selection tool of your choice, select just the stone, in this example I am using the quick select which takes all adjacent pixels of the same or roughly the same colour so stops at the black, which is where the stark background contrast proves essential. In the image below you will just be able to see the dotted line bounding box round the stone.

Select stone
Now while the stone is selected go to edit and hit copy, and then hit paste, this will give you a moveable copy of the stone which you can now superimpose over the silver. Generally the copy will be exactly over the original so you use the MOVE tool which is usually a large arrow with 4 smaller arrows for up down left right. (There are shortcuts to do this and if you know them use them this is for folks who do not.)

Copy stone

Now using the scale tool drag enlarge using only the corners so as to keep the ratio correct, until the stone fits the silver using the maximum available material avoiding any faults on the edge which may have occurred while hammering.



While this larger image of the stone is still selected, take a paint brush tool or pencil tool and choose a colour I have used red so you can see, and colour the whole of the larger stone image. This will be your cutting template once printed.

Template for cutting back-plate

Now to the hole in which the stone will sit which is the part I always find the hardest not using this method. Make another copy of the original stone and paste it again, position it centrally over the red template. Usually you can just hit paste again and it will be in the paste buffer, and you can also turn on grid in the view menu at the top to help you centre the stone.

Stone centred with the aid of Grid ( or near enough for this how to :0)


Then make another copy of the stone and paste it directly over the stone on the backplate, while it is selected use paint brush again and a different colour to colour it in, here shown in blue.

Colour the piercing template

Nearly done! Reduce this selection once again using only the corners, till the underlying stone (coloured black here to be clearer) is showing and you have a sufficient ledge for the stone to sit on once the back-plate is cut.





The final two steps are to measure the silver, from top to bottom in this case.




Measure sheet 
And now crop the whole image exactly to top and bottom of silver,

Cropped




Now print using the measurement you took of the silver in this case 3,5cm tall




The final cutting template for both the back-plate and the piercing.

Silver sheet cutting template and stone

now all you do is cut out the template stick it to your silver and cut as normal using the template to guide you.

It all seems long winded now that it is written out and illustrated but once you get the hang of it this is done in moments, apart from the bashing out of the silver at the beginning :0)

Here is one I did the other day finished with a prong setting but you can just as easily use a bezel setting now you have the stone seated in the sheet.

2cm tall Rose de France amethyst













4 comments:

  1. Wow Cornelius. Great idea. Thanks so much for sharing this. I will definitely give it a try on a couple of stones that I have been wondering how I could get a good seat for the cab to sit on securely.

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  2. Fantastic tutorial! This gives me mots of ideas!

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  3. This is so useful! Thanks so much for taking the time to put it together! Super helpful. :)

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