Reproduction scale - the ratio of the linear dimensions of the copy to the original . In turn, the linear size depends on the sweep speed and its duration. Therefore, the scale can be interpreted as the ratio of the products of the sweep speed and copy time to the original . In practice, either the ratio of the times is fixed, then the scale of reproduction is determined by the ratio of the speeds (the scan speed of the copy to the scanning speed of the original), or the ratio of the speeds is fixed, then the scale of the reproduction is determined by the ratio of time (the scan time of the copy to the scan time of the original). [one]
Mechanical scaling
The mechanical scaling is based on fixing the ratio of times, while ensuring a change in the ratio of speeds. In systems with a scan to the cylinder, the speed of the recording head is usually constant, and scaling occurs due to a change in the speed of the reading head. However, zooming in the horizontal direction (row direction around the circumference of the cylinder) is a big technical problem.
Electronic Scaling
The basis of electronic scaling is fixing the ratio of speeds. In ethical systems, the read speed is equal to the write speed. After reading the line, its analog-to-digital conversion takes place, after which it is sent to a temporary storage device. At the next revolution of the cylinder, the signal is output from the temporary storage. This signal controls the light source that exposes the film. Thus, the variable frequency was the clock frequency of the analog-to-digital converter . At the same time, the signal extraction rate did not change. But initially, this speed could be set taking into account the sensitivity of the photographic material , the power of the light source, sweep speed, lineature of the raster and other important parameters. [2]
Notes
- ↑ Chechug O.v., Ageeva A.I. Determination of the optimal parameters of images intended for direct printing on textiles // Bulletin of Tula State University. Technical science. - 2013. - Issue. 3 . - ISSN 2071-6168 .
- ↑ Technology for processing visual information: CHAPTER X. Format transformations of reproductions . www.hi-edu.ru. Date of treatment March 1, 2019.