Before the advent of the extract, marblers had to use the genuine , dried carregean moss/algae. it looks like a dried seaweed, brown in colour, and smelling somewhat of the sea.
25 grmas of dried carregean moss (NOT the extract, which is in the form of a powder)
1 tablespoon of borax
I litre of water.
1- put the ingredients into a pot , and heat them over a medium gas flame
2- let it boil for about half an hour. the water should thicken and turn brown.If the mix is thickening well, the bubbles in it should be fine and foamy. if it froths up voilently, or thickens to a syrupy consistency, add some water.
3- once it has reached the appopriate consistencey, let it cool down to room temprature for about 12 hours. Always remember, it is better to make a over-thick size, as you can thin it down, than an overly thin one.
If you so happen to have made an overly thin size, the only cure is to add some thicker size to it
The standard marbling size from the begining of marbling to the 19thc. , when carregean was introduced, and still used today in Turkey for ebru , it is a gum extracted form a species of tree.
The size is made thus......
Procure a large earthen pan, glazed on the inside, capable of holding fron 8 to 12 gallons. put therin about 1 pound of gum tragacanth, and pour upon it about 2 gallons of soft water. the next morning, stir it well with a birch broom for about 5 minutes; repeat this at intervals of three or four hours a day, adding more water as it thickens, or absorbs that which was first put to it. in 48 hours, you may first venture to make use of it, though 72 hours would be betterm and I have found some gum which has worked all the better when remainding a week in sollution. [ ......] when your gum is properly dissolved, you must gradgually dilute it with water till it is brought to the proper consistency , whan it must be starined through a hair or muslin sieve.
C. W. Woolnough- the whole art of marbling ( 2nd edition, 1881)
This material, which is more famous as a digestive aid, coame in the form of little seeds, which were placed in hot water to extract the mucilage.
Woolnough tells us that the size was made by taking a quarter of a pound of the seed, and pouring on it a gallon of boiling water, and stirring the result fro 10 minutes. Half an hour later, another gallon of boiling water was added, and stirring the mixture occasionaly. The thus thickened liquid, when cooled, was the size.
Woolnough also recomended that this material be mixed into the gum tragacanth for patterns that did not require to be combed or manupulated. like, the shell, spanish, italian, &c. , in a proportion of 1 quart of 1 quart of the fleaseed, to 2 gallons of the latter.
Another one from the health-food store! . This size is prepared in a similar manner to the fleaseed, but in a proportion of 6 tablesoppons of the seed to about a liter of Hot water, which is then heated in a slow cooker. The arrival of the mucilage is announced when the seeds start sinking, then the water growing cloudy. Once that is done, let it cool
The size has never been in wide use, as the mucliage turns watery after about a day. furtehrmore, the size is very thick, and only very simple patterns may be made on it.