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Uneven scanning quality

David Rosenthal Jul 10, 2012 12:37PM EDT

This is a follow up question to a prior post. I have included it below.

You had suggested I change the scan to greyscale. In my VB program I added
If ImTwain1.NegotiateCapability(Capabilities.Pixel_Type, 1) Then
and the image improved but the image size went from 15K to 750K. I was hoping for something smaller.

I was able to narrow down the condition that caused the poor scan. I am scanning a yellow page, with printed characters and handwriting. If the document has any handwriting in blue ink, it causes the whole scan to be poor. When I white out the blue writing, the scan is fine.

Any hints as to what to do?

Thanks,
Dave
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I am scanning documents that have both printed and handwritten B/W characters. Some documents scan fine while with others the printed and handwritten characters are very light. I use the following settings and save the file as a tif image.

If ImTwain1.NegotiateCapability(Capabilities.X_Resolution, 120) Then
End If
If ImTwain1.NegotiateCapability(Capabilities.Y_Resolution, 120) Then
End If
If ImTwain1.NegotiateCapability(Capabilities.Pixel_Type, 0) Then
End If

Any suggestions as to what to change?

Thanks.

1 Data Techniques Response

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DTI Support  Data Techniques Employee Jul 10, 2012 03:47PM EDT

Hi,

One option would be to scan as greyscale but then use our ImageMan.Net components to dither the image to black & white ie 1 bit. This may improve the quality in a scanner independent manner. The other option is to experiment with the brightness and contrast capabilities to better scan the blue on yellow.

Blue ink can be an issue particularly on a colored background.

Thanks for your interest in our products and please let us know if you have any questions.

Sincerely,
Sean
Data Techniques Support

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