EDINOL (Fr. and Ger., Edinol) A developer, known also as " Paramol," under which name it was originally introduced in iooi, but the two agents are stated by some not to be exactly the same. It occurs in a faint yellowish crystalline powder, having the formula OH and it is soluble in twelve times its weight of water. Its factor number is zo, and it therefore stands midway between the slow-working developers, such as pyro, hydroquinone, and adurol, and the quick working developers, metol, amidol, etc. It can be used as a single-solution or a two-solution developer, and works well when combined with hydroquinone. Edinol is extremely sensitive to the action of bromide as a restrainer, so much so that from io to 3o per cent. of a saturated solution of sodium bicarbonate instead of bromide has been recommended in cases of over-exposure. It is clean-working and is par ticularly suitable for bromide and gaslight papers and transparencies. The formulae for
one-solution and two-solution developers are as follow : Sodium sulphite . . 2 OZ. zoo g.
Water 5 „ soo ccs.
Dissolve and add Edinol . oz. 5o g.
Sodium carbonate . 21 „ 250 CCS.
and then add water to make to oz. This forms a concentrated developer, and for use is diluted with from five to ten times its volume of water.
Two-solution A. Sodium sulphite . 2 oz. roo g.
Edinol . . . 96 grs. ro „ Water to . • zo oz. r,000 ccs.
B. Sodium carbonate . . ro % sol.; or Potassium carbonate . 5 % sol.
Use equal parts of A and B. Sodium carbonate works slowly, and for quicker working potas sium carbonate may be substituted for it. (For use combined with hydroquinone, see "Devel opers, Mixed.")