The development and creation of paint most often happens in a laboratory far away from paint stores and job sites. Chemists and scientists spend hours upon hours formulating the exact right combination of materials to make a paint that performs exactly as they intend. From holding color, to protecting the substrate, to adhering to the surface and not cracking for years on end, formulating a paint that can be utilized in a production environment is a rigorous and detail-oriented process.

In the laboratory, these scientists and engineers count on a number of tools to help them make sure that what they are making can be repeated on a large scale and utilized by professional painters on paint jobs all over the world. And while tools like spectrophotometers, adhesion testers, and gloss meters provide a wealth of information about a paint’s true chemical characteristics, this represents only half of the test equation.

An automatic film applicator.
Image courtesy of BYK.

A big part of paint testing and evaluation is comparative analysis. But as with any sort of comparison, the characteristics not being tested or evaluated must be controlled. Otherwise, how can the scientist know that the data being gathered applies to the variable being tested? For example, when evaluating the gloss of one paint compared to another, the same light source should be used when evaluating both, or else the test results reflect the differing properties of the different light sources and not the paint itself.

One of the most important variables to control when evaluating paint in a laboratory setting is the thickness with which the paint is applied to the substrate. Applying paint to a draw down card or test surface with a uniform (and known) thickness means the technician, chemist, or engineer can accurately test the following paint properties:

• Color
• Gloss
• Haze
• Adhesion
• Drying / Curing Time
• Conductivity
• Transparency
• Hardness and resistance

Luckily, technicians have access to automatic film applicators to ensure consistency when testing. Automatic film applicators are most often small machines that provide uniform speed and pressure when performing a draw down with a rod or bar. Most automatic film applicators can accommodate a variety of draw down cards or test card sizes as well as paints and inks of varying viscosities. As a result, draw downs performed with the same automatic film applicator can be counted on to be of the same thickness. By comparison, manual draw downs will be less consistent.

Setting up an automatic film applicator.
Image source: Digplanet.com

Consequently, testing a paint without knowing the exact thickness of the test sample is largely useless. How will professional painters know how thick the paint should be applied to produce the intended result? It’s one thing for a weekend painter refinishing a rocking chair to add an extra coat or two to ensure proper coverage. It’s another matter entirely for a commercial paint company to lack accurate thickness measurements and application guidelines when putting together a bid to repaint an entire office complex. In order for painters to do their jobs well, they have to have complete confidence that the product they’re using has been properly and accurately tested.

Paint chemistry is a complex science with ever-changing rules and regulations in a market of constantly shifting demands and needs. Creating new paint products and coatings requires a full battery of tests to make sure each characteristic and trait of the paint meets the desired specifications of painters everywhere. Thankfully for the scientists responsible for this work, automatic film applicators are available to help the testing process run more smoothly. Click here to learn more about how other draw down cards factor in to your work as a professional painter!