Preparing for Pigment Consolidation part 2

Consolidation doesn’t attempt to restore the losses in the illumination, but instead focuses on finding areas where the pigment is actively deteriorating and then readhering the loose pigment to the surface of the parchment. Successful consolidation requires accurate identification of active damage and loss to the pigment.

Using magnification, in this case a Leica M80 microscope, it is possible to look at the paint layers very closely. The three-dimensional and high resolution quality of this magnification, which is not fully represented in the photos produced, makes identifying pigment problems much more accurate.

Under extreme magnification, everything can look problematic, but in many cases it can be a product of factors that are not damaging the fragments. Examples of this can be seen in the image below.

The orange arrow points to an area where the white paint was thickly applied, causing it not to adhere evenly. The smooth edges show that it isn’t cracking or flaking, and that the unevenness is original.

The red arrow points to an area of cracking paint. This can be from when the pigment dried after application and separated slightly. It is not actively moving, however, and so is not a problem.

The yellow arrow shows a spot of loss. This could be from particularly heavy application of paint that came off at some point, or if the fragment was mechanically damaged at some point in its past. However, since it doesn’t show signs of deterioration around the edge of the loss it is of lower concern.

There are several identifiers for active cracking and flaking. The pigment will often suffer from fragmentation of the surface, there may be shadows under cracks and crevasses between cracks, or cracks may appear very wide.

When I notice these indicators I zoom in to look more closely at the damage. The shadow the arrow points to indicates that the edge of the pigment is lifting, and when tested carefully the pigment did not appear to be firmly attached.

The other area of damage I look for under magnification is powdering. Powdering is the active crumbling or thinning of pigment leading to loss. Powdering of pigments is not as simple to identify without testing; however, there are visual indicators that point to potentially active loss of the pigment.

Two different examples of powdering pigment are presented in the photos below.

 Loss of the surface layer of blue in the blue initial is clearly evident. Enough pigment has been lost so the parchment underneath is clearly visible.

On the other hand, this yellow area didn’t appear to have any problems until viewed under strong magnification, where you can see how the pigment is thinning and how it’s surface is very pitted, indicating that loss may still be occurring.

Once I have identified problematic or active deterioration of pigment I will move on to consolidation, which I will explore in the next post.