Scales are designed to register a weight in an optimum window of weight i.e. bathroom scales measure from 50 to 100 kilograms with a 1 kg accuracy. General purpose kitchen scales weigh 10 grams to 1000 grams in 1-gram increments. Likewise laboratory scales that weigh accurately in small amounts (0.1/ 0.01-gram increments) cannot weigh very heavy amounts.

All scales have a minimum and maximum weight range and the optimum accuracy peaks in the middle and tapers to both sides. You would not use a 10-kilogram scale to weigh out a 0.1gram of pigment, as it is not designed to weigh such small quantities at the bottom end of its range. It would however, accurately weigh to 0.1g in the middle area of its weighing range i.e. at 5000.0g. Only a scale that is very expensive and has a split functionality, which is that the load cells can be programmed electronically, can weigh minute amounts of pigment at the beginning of the weighing.

So it is very important in colour matching and recording when making sample colours that the right scale is used to register small quantities, and not a production scale that weighs 10 kilograms and over. (See section on Choosing a Scale)

This requires that your sampling scale be used to weigh out the small additions required to make up the production colours e.g.

 
 
     
  Colour 1
4800.0g
  Colour 2
3200.0g
  Colour 3
150.0g
  Colour 4
25.0g
 
     
  Colour 1 and 2 could be weighed out on your production scale, while colours 3 and 4 would be weighed out on your sample scale. Note that colours 3 and 4 would be weighed out into your clean and empty container on your sampling scale. The other colours would then be added to the container on the production scale.

A CLEAN SCALE IS AN ACCURATE SCALE

All too often ink is dropped onto and down the side of the weighing pan. This ink will harden and form a stalagmite type restrictor - like a minute shock absorber. This and any other type of physical interference with the movement of the weighing pan on the pan cells, will cause inaccurate weighing. Ink that has seeped underneath the weighing pan edge and dried is one of the most common sources of inaccurate weighing.

Often a piece of plastic is taped to the pan to protect the surface from ink being messed while weighing. Although this is generally a good practice, too often the tape is attached in such a way that it restricts the movement of the pan especially when weighing towards the limit of the scales upper weight.

It is very important that the scale is switched off when cleaning and that the weighing pan is removed and cleaned separately. If the pan cannot be removed, then it must be cleaned very carefully.

 
     
 
 
 
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