This is a
tricky subject but it can't be dodged once bone set
restorations are being discussed.
Let's do a
little history first. Victorian
and Edwardian bone sets
provided an inexpensive alternative to ivory sets. When they were new, the bone sets looked much like ivory sets. Some of them were quite dramatic! Big pieces, flags or pennants "waving" from the rooks, elaborate details, bold colours.
Be they dramatic or modest, the Victorian English-made bone sets were undyed on the white side and usually dyed with cochineal (an expensive insect-sourced dye) on the red side. The Indian sets of the same era were also undyed on the white side and often dyed a green for the opposition--the source of this green in unknown, although verdigris from copper oxidation has been suggested. By the latter part of the Victorian era, the chemical composition of the dyes often shifted to less expensive sources such as aniline. This pattern of colour choices and dyes was similar throughout the Western world.
Over the years, some of these sets have suffered grievously. Bone yellows with age but, unlike wood, it does not truly take on a patina because it does not absorb oils and other contact- and air-borne substances readily. Bone instead gets dirty and/or faded and/or rubbed off.
Dirt is especially noticeable on the white pieces because accumulations and stainings of various foreign materials in the openings of the osseous (bone) structures on the surface of the bone contrast strongly against the white. Reasonably, fading and rubbing are most noticeable on the dyed pieces. Whether or not you like these effects is subjective. Some people do and others do not.
Ineradicable staining is often seen on one side of the solid-body chess pieces, because they were cut from sections of the large marrow bones and usually included a bit of the softer trabecular structure of the marrow side of the bone. These gathered dirt and other staining materials over the long years and the cumulative effects are permanent.
As a restorer, I have to decide what I am willing to do to a chess set or other antique. Whether or not to "fix" the dirtiness and dyes of any given set has to be decided for that set. Generally speaking, I am always willing to lightly clean a set, especially the white side, as this removes no more than surface grime. It is more like housecleaning than anything, and does nothing to the structure of the bone. Instead, the cleaned white pieces retain the creamy colour that is the result of decades (if not centuries) while shedding some (not usually all) of the blackness that has accumulated in various bone structural openings on the surface of the piece.
If you are thinking of cleaning the white side yourself, please write first! I will tell you the solution I use, as well as what to expect. You may not realize it, but most chess sets have been glued together here and there over the years, and the cleaning often will dissolve the glue joins. You have to brace yourself! It can all be fixed (and usually better, using pegs rather than glue) but the first glance can be pretty shocking.
if you wash the red side, it will fade. Cochineal and the later dyes are not
colour-fast in water. Please think hard before putting red antique chess set
pieces in water. The verdigris green of the Indian pieces is more stable,
but you still must be careful. Try wiping the bottom of a chess piece with
a dampened tissue and see what happens.
Okay. Back to the dye manifesto. I am not willing to re-colour the red or green or whatever side of a bone set except in certain circumstances. These circumstances are common, however.
1. Often a replacement piece or pieces must be made to complete the set, and the colour is impossible to match. To make the set usable again, I will bleach and re-dye the coloured side. Such was the case with this Edwardian folding travel set: I made the needed replacement pieces and the old red pieces were bleached and then the whole lot re-dyed.
2. The other case for re-colouring is when the dyed side has faded and discoloured to the point that my client & I agree that it is aesthetically horrible. (I did say this judgement was subjective!) Such was the case with this (probably) American version of the German Uhlig sets, which had faded and worn badly.
After serious discussion with the client, we agreed that I would bleach and re-dye the red pieces. I actually had to do this process twice as the first results, with a slowly set cold dye bath, were terribly uneven. Thus I had to bleach out that colour and re-dye with a quickly set hot dye bath then surface treat for irregularities then heat set the colour. The final result was satisfactory and the pieces were then polished. I also lightly cleaned and polished the white side.
If the second re-dyeing of the red side had been unsatisfactory, that would have been the end result regardless. I enter into this caustic bleaching/colouring process as a last resort only anyway, and will not continue to subject the pieces to it.
However, as you can see, the end result can be very gratifying.
So all of this is because I have been on a kick lately about restoring bone sets. They get broken easily and so can seem more of a disaster than they truly are. Many, many people simply have not realized that bone sets CAN be restored, and for a reasonable price.
With bone sets it is inevitable that the topic will arise of re-dyeing the coloured side, and so I thought I would go on and address it. It is a draconian solution, but sometimes is the only answer to sets that otherwise are ruined.
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