Printing what is underexposed
correct exposure of the screen can be faithful to the original, avoiding color pattern lines clear, dot printing drift. Overexposure may cause "diffraction" phenomenon that affects screen edge acuity reconciliation; lack of exposure is often, if not found in time, the machine printed, not only poor printing quality, waste materials, and the screen was difficult to recycle. Underexposed in several performances.
1. damage and pinholes in the process of developing
underexposed to the screen, appearing when water pressure, will cause the edges of irregular, film has a pinhole, photosensitive plastic flowing along the adhesive surface of the screen, or from mesh drips down. After discovering the problem to pass the test to determine the exposure time, and print again. Addition, exposure insufficient will effect to network version in press Shang of using life, for short version live didn't problem, if printing volume for thousands of printing or tens of thousands of printing, due to photographic rubber not full curing, network version image has may appeared pinhole or damaged, or due to strong corrosion solvent and ink of dip corrosion caused version film off, so, exposure insufficient of network version cannot Shang machine printing.
2. underexposed image incomplete
easily emulsion through holes into graphics and text that is not cured, after drying easy to form a transparent film on the screen through the mesh, resulting in incomplete printing images affect product quality.
it was suggested that by reducing the exposure time to improve the clarity of the pattern, it is actually wrong, because of insufficient exposure does not increase the clarity, clarity is in the negative contrast after you meet the requirements, with lines of resolution or dot the accuracy of printing edge quality. Improve clarity and cannot rely on reduced exposure time to improve, especially when printing a large quantity.
3. screen difficult to recycle
will appear underexposed consequences in the printing process, because the ink and solvent continuously into a poorly exposed photographic film of cross-linking, in conjunction with the screen so when dealing with difficult to take off plastic screen, causing screen scrap.