"Frank Lee" Blog

We are screen-printers so screens are the most important part of the process. A poorly made screen means bad printing and "production down-time". Remember my motto "time is money". Screen-printers buy everything they say they need, but many do not own a proper screen drying cabinet, making their own devices which frankly speaking are "junk", creating more trouble than they are worth.

Here it is, when dying a screen you must dry the screen with the "print side" facing the floor and the "squeegee side" facing the ceiling. Exactly as it is when you print with it.

Many questions are asked about the method and amount of passes when applying emulsion. Frankly, do what you need to do to get an even smooth coating making sure your last "cleaning" pass is made on the "squeegee side" forcing the heavier coating to the "print side" as discussed previously under "Screen Drying".

Humidity is not a good thing. The idea is to remove water from the process not to introduce more. If it has never been explained before then let me tell you, most "de-humidifiers" don't work, in fact, most introduce "more" humidity than they remove.

The small de-humidifiers that you buy at the local appliance store have such small fan motors that are over worked and they heat up. That heat causes the coil on the back of the unit to sweat. That sweat drips into the pan that you empty every day. Put your hand to the unit and tell me if you feel warm or cool air blowing out the back?

Epson and other printers setup these devices to have a "zero tolerance" when it comes to ink. If one ink is out then the printer stops working. If one computer chip on a cartridge goes bad then the printer stops printing. If you get a new set of inks and one cartridge is damaged then the printer will not print.

Color mesh reduces the amount of light that "bounces" around during exposure which is most important when exposing films with fine halftone spots. I recommend the use of colored mesh such as yellow.

There are multiple light source units and single point light sources. Obviously, single point light sources control the light better and are advised to be used for more detailed film exposure. Multiple units scatter light and attack the films from multiple angles creating "undercutting" that reduce screen accuracy.

A tight seal between the screen, film and the exposure unit glass it critical to prevent "under-cutting". Under-cutting is when light creeps around the dark areas of the film positive and exposes the emulsion beneath it to light.

The tighter your screens are the brighter your prints will be. The tighter your screens are the less squeegee pressure is required to print properly. How much pressure do you think it takes to push ink through a screen anyway?

Roller frames allow you greater control and the ability to re-tension. Aluminum frames are good and hold tension for as long as the mesh does not stretch but it eventually will and requires a stripping and re-gluing process.

There are many shapes and sizes and all are designed to "sheer" the ink from the mesh and transfer the ink to the garment. I'm not going to get too deep here as there is so much to cover and the manufacturers will send me tons of letters defending each size, shape durometer and such.