Presentation is loading. Please wait.

Presentation is loading. Please wait.

WELD LAKE PREPARATION Jo Kirby and Catherine Higgitt National Gallery, London May 2005 Eu-ARTECH organic project.

Similar presentations


Presentation on theme: "WELD LAKE PREPARATION Jo Kirby and Catherine Higgitt National Gallery, London May 2005 Eu-ARTECH organic project."— Presentation transcript:

1 WELD LAKE PREPARATION Jo Kirby and Catherine Higgitt National Gallery, London May 2005 Eu-ARTECH organic project

2 Reseda luteola L. English weld French gaude Dutch wouw German Wau Italian reseda

3 Recipes fell into 3 broad categories 1.Extraction of dyestuff with limewater solution, then alum (+chalk) added to precipitate lake - Use Boltz von Rufach 1549 2.Aqueous extraction of dyestuff, then alum and chalk (or other Ca salt/lead white) added to precipitate lake - Use 15th C Sienese/Bolognese recipe for arzica 3.Alkali added to aqueous solution of dye (or weld boiled in alkali), then alum added to ppte - Use Dossie, 1758 as example of this type

4 Recipes – substrates 1.Boltz von Rufach 1549 (lime water; alum/chalk) - Ca, Al, O: Hydrated alumina/chalk/calcium sulphate 2.15 th C Sienese/Bolognese (alum/chalk) - Ca, (Al): Chalk (trace of hydrated alumina?) 3.Dossie, 1758 (alkali, alum) - Al, O: Hydrated alumina

5 Recipes Most of the examples of yellow lakes we encounter in paintings are pre-1800 so deliberately avoided 19 th C recipes Steps in manufacture –Extraction/boiling –Removal of plant material –Precipitation of lake –Filtration and washing of lake –Drying and grinding of products

6 Dry weld – broken up before use

7 Extraction time

8 Filtering extract

9

10 Filtrate

11 Precipitation – Lake 3 – (i) addition of K 2 CO 3

12 Precipitation – Lake 3 – (ii) addition of potash alum

13 Precipitation – Lake 1 – addition of chalk/alum mix

14 Precipitation – Lake 1

15 Precipitation – Lakes 2 and 3 – settling out

16 Filtering lake

17 Filtering and washing lake eventually

18 Filtering and drying lake

19 Grinding Lake 3

20


Download ppt "WELD LAKE PREPARATION Jo Kirby and Catherine Higgitt National Gallery, London May 2005 Eu-ARTECH organic project."

Similar presentations


Ads by Google