50 Mr Laurie, On Vehicles used by [Feb. 24, 



When I began I imagined that the old masters made use of a 

 few absolutely unalterable pigments and in this way ensured the 

 permanence of their pictures. I soon found this view to be 

 erroneous. Many colours were described which were so fugitive 

 that no modern artist would use them. Red, yellow, blue, and 

 green lakes, for instance, prepared from vegetable dyes, some of a 

 most fugitive character under the action of air, moisture, and 

 daylight. Many of these colours may have been only used for 

 illuminating parchment, where, kept from light and moisture, they 

 might doubtless be permanent ; but there seems to be no reason 

 to doubt that many were used in the oil painting of pictures. 

 How then did these men succeed in using in oil painting colours 

 known to be very fugitive and therefore avoided by modern 

 artists ? 



In order to understand how this might be successfully done we 

 must turn to the recent experiments of Captain Abney and Prof. 

 Russell on the permanency of water colours, published in July, 

 1888 (Government report). They have tested the action of sunlight 

 on water colours, and they find that in dry air many pigments are 

 permanent that fade in moist air, and that in vacuo hardly any 

 colours are altered. If then we could ensure the absence of 

 moisture and air, many of these colours now regarded as fugitive 

 would doubtless be permanent. Turning again to Eastlake, we 

 find that evidently the old masters quite understood this, and that 

 they took especial pains to lock up fugitive colours by the intro- 

 duction of some varnish ; but before going further let us put down 

 briefly what vehicles were used by them for painting. They made 

 use of a fine size prepared from parchment, gum arabic, white of 

 egg, yolk of egg mixed with fig-tree juice and so on, but the use of 

 oil was long difficult on account of its slowness in drying. It was 

 soon found, however, that certain oils, such as walnut oil, poppy 

 oil, and linseed oil, had the property of becoming converted into 

 hard resins in time, the process technically called drying, and that 

 this process could be hastened by exposing the oil before use for 

 some time to the sun or by boiling it, boiled oil drying quicker 

 than raw oil. It was next found that by boiling the oil with 

 litharge or white lead it would dry still quicker, and was therefore 

 more suitable as a vehicle for colours. It was also known that by 

 dissolving in oil certain resins, such as amber, sandarac, Venice 

 turpentine, and perhaps copal, and later mastic, that varnishes 

 could be prepared. These facts were known before Van Eyck, and 

 he had these materials from which to develope his method of 

 painting in oils. There can also be no doubt that boiled oil did 

 not afford a sufficient protection for fugitive colours, and that 

 therefore a varnish must be ground with the colour to coat each 

 particle, and so protect it from the action of air and moisture. So 



