(2624) Recipe for Chrome Ink.

The Manufacturer and Builder 6, 1881

There are a number of recipes given for making chrome ink, or Runge's ink, as it is sometimes called, from the name of the chemist who first proposed it. Boettger, a well known chemicl technologist, givest the following directions:
Take of extract of logwood, 15 parts;
water, 1,000 parts;
crystallized carbonate of sodium (common washing soda), 11 parts;
neutral chromate of potassium, 1 part.
Dissolve logwood extract in 900 parts of water, allow it to deposit, heat by boiling, and add the soda. Lastly add, drop by drop, with constant stirring, the chromate of potassium, dissolved in the residual 100 parts of water.

The following recipes are recommended by Krüger:
(1) Dissolve 1 pound of extract of logwood in 15 pounds of water, add 1 ounce of alum, and ½ ounce of yellow chromate of potassium.
(2) Boil 10 pounds of beet rasped logwood with 100 pounds of water down to 80 pounds. Whend cold, add 1½ ounces of yellow chromate of potassium on logwood almost instantly produces a deep blue-black liquid (or dye), suitable for writing purposes. But it is found that on exposure to the air, the liquid frequently decomposes and deposits its colorin matter in the form of large black flakes, leaving the supernatant liquid almost colorless. This peculiar behavior, which doubtless has been observed by all who have made or used this ink, is its great fault, though in other respects it has all the qualities requisite for a good writing fluid. It is cheap, readily prepared, does not corrode steel pens, and makes a permanent stain on paper which can only be removed with great difficulty. To avoid the clotting or gelatinizing of this ink, is the object to the addition of soda or alum in two of the above recipes; but from our own experience they are not always effective. It is probable that the quality of the logwood may have much to do with the rapidity with which clotting occurs, and on this account it will be found best to use logwood chips instead of the extract, which varies greatly in quality. Again, it will be best to make only a little of the ink at a time. By following these directions, the trouble above named will be generally avoided.