QUALITY SCANNING:
Creating high quality scans for raster to vector conversion
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Do not save your scan as a JPEG file
We recommend that you save your scans as TIFF files. If your scans are black and white, save them as TIFF Group 4 files. This will compress your scans without causing any loss in their quality.
Do not save your scans as JPEG.
JPEG uses "lossy compression", which means that it discards data it thinks you can do without. This causes it to decrease the quality of your scans by blurring the details and adding speckle artifacts. This means that JPEG files usually require extra raster cleaning steps before they can be vectorized. Some JPEG files can never be cleaned to the point where they can be successfully vectorized.
The smudging and grey "clouds" surrounding the lines in the images below are typical artifacts caused by saving scans as JPEG.
Smudging and speckles caused by saving scans as JPEG.
Once you have damaged an image by saving it as JPEG, you cannot undo the damage by simply converting the JPEG image to TIFF. You will need to rescan the drawing.
Finally, if you are scanning and saving images as PDF files, use TIFF compression rather than JPEG inside the PDF when saving. For more information about scanning to PDF, click here.
Q&A: ASK AN EXPERT
Q: I'm told that 48-bit colour capture is best. Is this true?
A: No, it's untrue that 48-bit colour capture is best. 36-bit colour capture is as good and if you are buying a scanner for scanning technical drawings it's irrelevant anyway!
While some large format scanners capture colour in 24-bit and output it as 24-bit, most scanners capture colour in 48-bit or 36-bit and output "the best" 24 bits as 24-bit.
To give you some idea of the numbers of colours we're talking about:
* 48-bit - 281475 billion colours
* 36-bit - 68.7 billion colours
* 24-bit - 16.7 million colours
* 8-bit - 256 colours
36-bit colour capture captures the entire range of colours that can be represented on the best quality scannable media (film transparency).
As 36-bit colour is capable of capturing all the colours that can be represented the additional colours captured using 48-bit colour add nothing to the range of colours that can be captured or used - they simply slow down the scanning process by piling in more data and creating bigger files to work with. And that takes time.
So, in conclusion, the statement which we think is most correct is "36-bit colour capture is best". It gives you all the benefits of 48-bit colour capture without the time and hassle involved in processing extra, useless information.
Why has this misconception occurred? Because bigger sounds better!
We're happy to answer questions! Click here to email us.
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