impregnated paper.pps

Replacing varnishes on architectural drawings on impregnated paper

Rita UdinaPaper & book restorer. Barcelona (SPAIN)

Symposium Technical drawings and their Reproductions The Hague 6-7 October 2014

Replacing varnishes on architectural drawings on impregnated paper www.ritaudina.com

Shellac Transparency


Shellac Oxidation (yellowing)

Oxidation Fragility Cuts



Bends Cuts …. Scotch tape

Fragility


Cracks, tears


Goals to achieve with the restoration treatment:

• Stop oxidation, or even revert some of its consequent acidification.

• Retrieve lost flexibility.More flexible Less consolidation (layers) needed


Being aware of:• Importance of transparency

main purpose from the addition of shellac).

• Strict maintenance of scale(plans/maps).

Less important:

• YellowingConsequence with no damage by itself.


Shellac

• Transparency,• Oxidation• Brittleness

Other varnish

• Transparency,• RedOx stable• Flexibility

Maintenance of scale:Avoid aqueous treatments?


Treatment case 1

• Impregnated laid paper

• 1918

• Ink, watercolour.

• Several fragments (40 x 60 cm aprox.)

• 90 µ thick


Treatment case 1


Treatment case 1. After varnish removal (ethanol)

Loss of transparency (watercolour seen only on the back)

Flattening,Adding missing areas


Washi paper + paste

Lining

Apply varnish

Watercolour shows again Paraloid B72, 50gr/L

Tainted washi paper+ Beva Film(+ Klucel )

Treatment case 1


Treatment case 1

cracks

tears


Results


Characteristics Before After

Innocuous

Transparency Good, though not excellent when lining.

Intense colour tone OK

ScaleGuaranteed even with aqueous treatments

Detrim

ental

Ongoing oxidationDue to shellac

--- Significantly reduced

Acidity pH=5,0 pH=7,0Significantly reduced when aqueous tretament is possible

BrittlenessUnsafe

handlingSafe

handlingExcellent improvement

Yellowing A lot Still a lot Insignificant improvement



Innocuous


Intense colour tone OK


Detrim

ental




BrittlenessUnsafe

handlingSafe



TRANSPARENCY

Good though limited when lining.

Slightlier opaque

Improvement suggested

Use of Gampi paper instead (more homogeneous appearance, wouldn’t intefer that much on transparency)



Innocuous


Intense colour tone

OK


Detrim

ental




BrittlenessUnsafe

handlingSafe





Innocuous

Transparency Not bad, though not excellent when lining.

Intense colour tone

OK


Detrim

ental




BrittlenessUnsafe

handlingSafe





Innocuous

Transparency Not bad, though not excellent when lining.

Intense colour tone

OK


Detrim

ental



Acidity pH = 5,0 pH = 7,0Significantly reduced when aqueous tretament is possible

BrittlenessUnsafe

handlingSafe





Innocuous


Intense colour tone

OK


Detrim

ental




BrittlenessUnsafe

handlingSafe





Innocuous


Intense colour tone

OK


Detrim

ental




BrittlenessUnsafe

handlingSafe



Diminishing yellowing depends on varnish remnants and oxidation degree


Other aspects

Applicability Presence of stamps, scotch tape, techniques (ink, watercolur, graphite), papers (diferent thicks…).

Reversibility

Toxicity

Ethanol bath

Ethanol + Toluene bath


Contact details:

Rita [email protected]

Further information soon at my blog:http://ritaudina.com(subscribe by email)

Thank you!

impregnated paper.pps

Documents

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