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It is possible for a single-color stamp to be inverted relative to watermark, but this is called an "inverted watermark" rather than an "inverted stamp". Depending on the positioning of stamps within their sheet, the invert may be perfectly centered (as with the Inverted Jenny), or offset. Inverted overprint on a 1919 stamp of Siberia
The Crown CA watermark found on many British Commonwealth stamps (seen from the reverse) A US postal stationery envelope from 1883 showing a clear watermark on laid paper In philately , the watermark is a key feature of a stamp, and often constitutes the difference between a common and a rare stamp.
A digital watermark is called imperceptible if the watermarked content is perceptually equivalent to the original, unwatermarked content. [7] In general, it is easy to create either robust watermarks or imperceptible watermarks, but the creation of both robust and imperceptible watermarks has proven to be quite challenging. [2]
If the data file to be retrieved is an image, the provider can embed a watermark for protection purposes. The process allows tolerance to some change, while still maintaining an association with the original image file. Researchers have also developed techniques that embed components of the image within the image.
True watermark. A true watermark is a recognizable image or pattern in paper that appears lighter or darker than surrounding paper when viewed with a light from behind the paper, due to paper density variations. A watermark is made by impressing a water coated metal stamp or dandy roll onto the paper during manufacturing.
Normal – When the watermark coincides with the design of the stamp when viewed from the front of the stamp. The watermark will be mirrored when viewed from the back of the stamp. Inverted – When the watermark is upside down when viewed from the front of the stamp. That is, when the stamp's printed design is right side up and the watermark ...
Caution: Before removing a watermark from a copyrighted image, please read the WMF's analysis of the legal ramifications of doing so. Requesting work .
Microsoft Excel 4/5/95 XLS, XLW, XLT Spreadsheet Yes Up to 3.6 [77] Microsoft Excel 97–2003 XLS, XLW, XLT Spreadsheet Yes Yes Microsoft Excel 2007-2021 XLSX Spreadsheet Yes Yes Microsoft Excel Web Query File IQY Data sources, text From 5.4 [78] No Microsoft Office 2007-2021 Office Open XML: DOCX, XLSX, PPTX Multiple formats Yes Yes Microsoft ...