There are various ways of developing screens for printing. Some of these have been detailed in discussion below. Choose us, we are professional screen printing equipment hot sale Exporters
1. Paper Stencil Screen Preparation- This paper stencil screen is very similar to the stencil preparation though this is an extension of it. It involves the transfer of the finished design onto the paper to be used, while cutting out the positive areas (the image to be printed) of the paper. The prepared stencil is then attached to the stretched screen block with the aid of a masking tape. Enough allowances are left to serve as ink reservoirs. The screen is ready for printing.
2. Candle Wax screen/Shellac Screen /Lacquer screen preparation- The preparatory processes in these
methods of screen preparation are the same. The only difference is the material used in coating the
negative areas of the screen which may either be molten wax, shellac or lacquer. The finished design
is transferred onto the stretched screen block. With the aid of a brush, apply the molten wax or thinned
shellac or lacquer to block the negative areas of the design. Test screen for pinholes by doing a test print.
Block pinholes if there are any. The prepared screen is ready for printing. Lacquered screens are very
durable and more economical in terms of quality and quantity. They are very good for simple, bold
3. Photographic Screen Preparation- The photographic screen preparation involves the use of light in developing or bringing out designs onto the screen. The sources of the light can be natural or artificial. Therefore, there are two main ways of making photographic screens thus the use of the solar energy (sun) during the day and the use of the strong fluorescent bulbs in the exposing or shooting box. In all these two ways, the screens have to be coated in the darkroom with a solution of photo emulsion mixed with a sensitizer. The screen is placed in the dark room to dry.
In the solar energy method, the inside or hollow part of the coated screen is filled with a sack of fine sand on a flat wooden board and turned upside down. The positive part of the paper (where the designs are) is placed on the frontal part of the screen and covered with a piece of cloth. The whole thing is exposed to the solar energy (sun) for some few minutes. The duration is dependent on the intensity of the sun. The screen is then removed and washed under running water. The design areas will be left open with the negative areas blocked.
In using the developing or shooting box in the dark room, after the screen is coated with the photo emulsion and sensitizer solution, it is left to dry. The design is then placed with face up on the glass of the shooting box. The frontal part of the dried coated screen is placed on the design with the inside or hollow part up. A sack filled with fine sand or heavy clothes hinged with stones are placed in the hollow part of the screen just to ensure firm contact between the glass plate, the paper with the design and the screen. The lights in the shooting box are switched on for about five minutes. The duration can be more or less depending on the number and watts of the fluorescent bulbs in the shooting box. The screen is removed and washed under running water. Afterwards, it is dried and ready for printing.