Pre-Treatment Assessment - Visual assessment

Birgit Reissland, Karin Scheper and Sabine Fleischer (2007)

 

Day light

 

> Large areas covered with ink? Areas with a high quantity of ink (washes, wide quill strokes) are of risk, since the water uptake in those areas is different from the surrounding non-inked paper. Formation of fine paper cracks or even losses within the ink area are likely to occur during aqueous treatment, especially if the areas are already degraded by ink corrosion and the verso shows dark brown discolouration.

Risk: (further) mechanical decay, formation of cracks in the paper of inked areas.

References: (Reissland 2001)

 

left: areas with a high amount of ink are of risk

right: thick ink lines, especially intersections, form a risk

 

> Dissolved ink in areas of previous water damages? Inks that once dissolved in a liquid (e.g. water), might still be soluble! This test gives an essential indication, but it should be taken into account that the solubility parameters of the ink might have changed over the years. Always check the verso and recto for old water damages.

Risk: loss of ink, bleeding

 

left: Recto with old water damage

right: Verso with old water damage

 

> Ink-transfer technique? Ink-transfer techniques are historical techniques used to create a direct copy from an original. These techniques are widely used throughout the 19th and beginning of the 20th century. Originals and copies produced with these techniques pose a challenge to the conservator for several reasons. In order to create an easy to copy original, particular writing inks were used containing hydrophilic additives like glycerin or sugar to enhance the inks ‘open time’. Often, these inks remain quite water soluble. Furthermore, the location of the ink is crucial. While on the original, the inks are applied on the recto side, they are always located on the verso (!) side of a copy created with an ink-transfer technique. A homogeneous “blurring” effect over the entire written area, with uniform halos around the ink lines, is characteristic for both the copied original and the copy. Thin, transparent papers with a blurry ink appearance are likely to be a copy.

Risk: loss of ink, ink bleeding
References: (Cleveland 2001, Rhodes and Streeter 1999, Dobrusskin 1999)

 

left: typical homogeneous halo-effect around the ink on a copied original

right: no copy, since the halos around the ink are not homogeneously distributed.

 

Microscope / raking light

> Thick ink layer? Thick layers of ink on top of the surface size of a paper support tend to be sensitive during aqueous treatments. Dissolution of the binding media of the ink, the ink components or the paper surface size cause thick ink layers to change appearance or to disappear. Leaf casting techniques or close contact between paper surfaces during treatment are of great risk for thick ink layers.

Risk: loss of ink, ink bleeding, change of layer morphology, change of ink appearance and gloss

 

left: thick ink layer before treatment

right: ink layer lost after treatment

 

> Drying material present? Blotting sand and blotting paper were applied to wet ink for centuries with the intention of speeding up the drying time of writing inks. Blotting sand consists of little particles and can be made of a variety of materials (minerals, bio-minerals, glass, metal and others). Blotting sand particles, or fibres of blotting paper, are part of the authentic original. Deliberate removal of these materials means acceptance of the loss of potentially relevant information.

Risk: loss of authentic material, containing potentially relevant information
Reference: Reissland et al. 2006, Milke et al. 2003

 

left: Blotting sand on ink

right: Ink layer after complete removal of the blotting sand particles

 

> Deposits on ink? Either deposits dissolve or they are formed during treatment. Some deposits even “survive” the treatment. Deposits on inks change the ink appearance. To distinguish if deposits appeared or disappeared during treatment, it is crucial to document if deposits were present already before treatment.

Risk: change of ink appearance, formation of deposits
Reference: la Camera 2004, Reißland 2001, Fuchs et al. 2000, Reissland 1999

 

left: ink line covered with a deposit consisting of a yellow and a white component

right: ink with a deposit

UV-lamp

>Ink appears darker? Halos under UV? If an ink appears darker under UV, it is an indication that it might be iron-gall ink. However, this information provides no absolute evidence. Often, areas of risk become visible under UV which are not recognizable in day light. For instance, around ink lines, halos can appear either fluorescing or darker coloured. These indicate either the presence of (degraded) ink components which have migrated out of the ink lines into paper areas in close vicinity to the ink lines, or degradation of the paper area around ink lines caused by such components.

Risk: some fluorescing compounds are soluble in water and might spread over the paper
Reference: Reißland 2001

 

left: Water damage more visible in UV

right: Fluorescing halos around ink lines

 

Transmitted light

> Cracks in inked area? Areas of risk (cracks) that are not recognizable in incident light become visible in transmitted light. Transmitted light examination can be carried out either on a light table or, depending on the objects condition, by carefully holding it against a light source, if necessary on a transparent support like Plexiglas. Always include one or more pre-treatment photo(s) in transmitted light into your documentation! Especially close-up photo’s will aid to distinguish which cracks resulted from treatment.

Risk: further mechanical decay

 

left: Detail before treatment

right: Detail after treatment, cracks and losses are noticeable on the close up