How is it performed?
As a first step should be an adequate textile support to the task, depending on the final resolution of the pattern, for example, to print a poster should be used muslin, with approximately 20 threads, or a tiny picture is desired used synthetic silk screen printing, because it has more than 100 threads and thus be smaller holes.
The preparation of the frame is very similar to the preparation of canvases for oil painting. It muslin or silk screen printing frame wooden or metal frame tense, considering that the textile surface should be tensioned until it creased, but at the time of printing does not tear. Usually staples it is holding the wooden frame of a tuning point at a time and crosswise, this in order that the voltage is flush on all corners.
Can be made from different materials, until recently were made with a sheet of clear acetate which was painted with marker or ink, another method was to copy in clear acetate, currently performed by thermal printers designed exclusively for this purpose and using exclusive high quality film or conventional printers on the common bond paper, 75 grams, which is painted on the reverse with almond oil, this makes the paper becomes transparent and allows the burning of the plate.
There are various emulsions on the market, depending on the ink that is printed, the most common is the emulsion fotoserigame blue color, which is used for printing with water-based inks and benzene-based (mineral spirit) there is also the red emulsion for printing with PVC-based inks, this is not resistant to water-based inks, these emulsions are activated with ammonium dichromate.
To make the printing plates must be done in darkness or twilight, or using safety lamps.
Is added to the emulsion dichromate ammonia in the amount declared by the manufacturer, they are usually a few drops, remember that these materials are sensitive, it is best to store them in a dark or in plastic bags in black site, once prepared the emulsion is spread evenly with a channel or a spatula on the frame with stressed silk and allowed to dry in a dark or with the aid of a hair dryer site, once dried, the emulsion becomes somewhat transparent.
To burn the plates a light source, usually a drawing board for tracing the emulsion reacts depending on the amount of light so it is important to test to determine the exposure time, usually for a drawing board it is used is exposed for no more than one minute, you can also use the focus of a room, it should be exposed for approximately 20 minutes or use lamps drawer built for this purpose, with several fluorescent lamps.
Taking the frame with the fotolito dried emulsion, also called art, made under it is located, the goal is to make the black parts of fotolito not to miss the light to certain parts of the coated silk, therefore, in these parts the emulsion will not be cured and may be subsequently washed, keep in mind that there must be no space between the photolithography and iron, for this book or anything that press on fotolitos silk are used.
After exposure of the plate proceeds to reveal, at this time you can leave the darkroom into a sink, gently silk by hand or with a brush rubs the parties that were not exposed to light is easily diluted leaving the silk white, do not rub a lot because all of the emulsion will fall. Should parts of the iron do not reveal is because the iron was overexposed, otherwise if the entire sheet is blank, it is because it was underexposed and needed more time to react.