Often large drawings/blueprints require shorter and more scalable versions for references. Hence scanning is needed. But to do the scan, the drawings need to be digitally treated. Photographs are taken in high resolution. Then the large images need to be scaled so that the scan is easier. The photo editor often treats such blueprints if the images are in raster-i.e. if they are not scalable. Converting raster to vector is the first step before the editor takes over the job. He does that by changing the contours of the drawings. If he receives the drawings in the original format then he first needs to check if they are in a condition to be converted from raster to vector. Why does this happen? The drawing may be very faint and thin and may not catch the ink marks. They cannot be scanned to CAD. Hence converting from raster to vector becomes mandatory. Then only the image will be clean. If the sketches contain too much text, or overlapping notes, the clarity is in doubt. Even messy patterns and double sketches can be responsible for a poor scan or even converting it from raster to vector. In this case even if the resolution is high it will not amount to clarity.
To avoid the poor quality of the final prints, several things go into consideration. The original drawing needs to be sent to the editor to make a checklist where it needs improvement. Then the process of conversion is done. Most drawings and sketches are done in black ink or sometimes in blue ink on a white background. Keeping this in mind the editor is able to create the clear background first. This also should be able to remove the wrinkles (often the original drawing is folded or rolled). Once the wrinkles are also ironed out, a proper conversion from raster to vector is possible. When the actual process begins, how the editor saves the work is essential. If the images will eventually be scanned then TIFF files are the best for scanning. They give the maximum clarity.
The right resolution is also important for the conversion. If the resolution is lower, the quality of the scan is very poor. It will be blurred or smudged. The resolution is measured in dpi i.e. dots per inch. A minimum of 300 dpi is ideal for converting raster to vector. Anything less is a patchy job. The resolution gives proper shape to the edges of the drawing. The lines are distinct. When the lines and the curves are distinct then vectorization is easy. Normally less than 300 dpi image cannot be used for converting raster to vector. The details, sharpness will also be missing. The drawing also might look distorted. And this isn’t easy for the scan. Once re-scanning is done, and then there are chances of the drawing getting a better resolution for converting from rector to raster to vector.
Essential Tip for conversion:
Before scanning consult an experienced photo editor before the job execution. It will cut the unnecessary time consuming process of re-scans, if the requirement is urgent.
About Author:
Atiqur Sumon
Chief Executive, DTP & SEO Expert at Outsource Experts Ltd.