Those of us in the printing industry like to think of a triple beam balance as “an ink scale.” In reality, the primary use of a triple beam balance is in the scientific community. As a result, the biggest demand for triple beam balances is in metric graduations and this has caused the discontinuation of the English (or, ounces) version of the Ohaus triple beam balance. Printers – do not despair! They did us a favor. Weighing ink in grams (using the percentage formulas) is far easier than ounces and the parts formulas. Just give me the chance to show you.
The English System
The basic unit of weight (more correctly, mass) in the English system is the avoirdupois pound (sounds French to me). The pound is divided into 16 ounces. The early ink mixing formulas were in “Parts” and the total number of parts was 8, 16, 24 or 32, all numbers that formed easy fractions with the 16 ounces. All was happy in Litho Land. Then came ink formulas with “unfriendly parts”, such as PANTONE 525 (12 and 1/2 parts PANTONE Purple, 3 and 1/2 parts PANTONE Green and 4 parts PANTONE Black). This was 20 parts and every part was now 1and 1/4 ounces. Instead of mixing one pound of ink, as the parts formula tended to do (whether or not you needed this much), you were now mixing 20 ounces or 1 and 1/4 pounds.
PANTONE 530 totals to 64 parts (3 and 1/8 parts PANTONE Purple, 7/8 part PANTONE Green and 60 parts PANTONE Transparent White). Use the premise that one part equals one ounce and you are mixing four pounds of ink! What if you only need an estimated one-quarter pound of ink for the job? What do you weigh for the PANTONE Green that is listed as 7/8 part? (Answer = 7/32 of an ounce. Good luck!)
The Metric System
Everything in the metric system is based on units of 10. For example, 10 grams equals a decigram; 100 grams equals a centigram (10 x 10 = 100); 1000 grams equals a kilogram (10 x 10 x 10 = 1000). Let’s look at mixing the PANTONE 530 using the metric triple beam balance instead of ounces.
We had determined that we needed about 1/4 of a pound of ink. This is roughly 115 grams. For simplicity, I am going to weigh out one hundred grams. The PERCENTAGE FORMULA in the current PANTONE formula guide lists the formula as 4.9% PANTONE Purple, 1.4% PANTONE Green and 93.7% PANTONE Transparent White. This is a piece of cake! Just weigh out 4.9 grams of Purple, 1.4 grams of Green and 93.7 grams of Transparent White! What could be more straightforward? And you wanted ounces on your scale! Why?
The Convenience of 100 grams of Ink
To be more precise, one pound equals 453.59 grams. One hundred grams is 0.22 pounds, or about half way between 1/4 and 1/5 of a pound. This is the amount of ink used by a duplicator press for an average job. So just weigh out the components for 100 grams of ink and you will have the right amount of ink for your job with a minimal amount of waste.
What about the long run? Simple! Instead of thinking about mixing a pound of ink, think about mixing 500 grams of ink. Taking the above formula, just multiply each component by 5 for the amount needed. You would get 24.5 grams of Purple, 7 grams of Green and 468.5 grams of Transparent White. Need a half-pound of ink? Multiply by 2.5 for the amount.
Just think that 1/4 pound is approximately equal to 100 grams and one pound is approximately equal to 500 grams and you have simplified your ink mixing.
The Ohaus Triple Beam Balance is shown above with the optional weight set. The front beam is used for measuring grams in 0.1 gram increments (total of 10), the back beam for increments of 10 grams (total of 100) and the center beam measures increments of 100 grams (total of 500). This gives the scale a total capacity of 610 grams without the optional weight set. This allows it to be used to weigh out approximately 1 and 1/4 pounds. The optional weight set increases the scale’s capacity to 2,610 grams.
The screw, visible under the pan at the 8 o’clock position, is used to zero out the tare (what you are weighing the ink on, such as a sheet of paper or plastic).