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  2. Physiognotrace - Wikipedia

    en.wikipedia.org/wiki/Physiognotrace

    A pantograph connected to a pencil produced within a few minutes a "grand trait", a contour line on a piece of paper. With the help of a second scaling-down pantograph, the basic features of the portrait were transferred from the sheet in the form of dotted lines to a copper plate, which had previously been prepared with a ground for etching.

  3. Void pantograph - Wikipedia

    en.wikipedia.org/wiki/Void_pantograph

    Void pantographs work by exploiting the limitations and features of copying equipment. A scanner or photocopier will act as a low-pass filter on the original image, blurring edges slightly. It will also not be perfectly aligned with the directions of the document, causing aliasing. Features smaller than the resolution will also not be reproduced.

  4. Pantograph - Wikipedia

    en.wikipedia.org/wiki/Pantograph

    Drafting pantograph in use Pantograph used for scaling a picture. The red shape is traced and enlarged. Pantograph 3d rendering. A pantograph (from Greek παντ- 'all, every' and γραφ- 'to write', from their original use for copying writing) is a mechanical linkage connected in a manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical ...

  5. Non-photo blue - Wikipedia

    en.wikipedia.org/wiki/Non-photo_blue

    The difference between the non-photo blue and black ink is great enough that digital image manipulation can separate the two easily. If a black-and-white bitmap setting is scanned in, the exposure or threshold number can be set high enough to detect the black ink or dark images being scanned, but low enough to leave out the non-photo blue.

  6. Defective pixel - Wikipedia

    en.wikipedia.org/wiki/Defective_pixel

    Close-up of an LCD, showing a dead green subpixel as a black rectangle A defective pixel or a dead pixel is a pixel on a liquid crystal display (LCD) that is not functioning properly. The ISO standard ISO 13406-2 distinguishes between three different types of defective pixels, [ 1 ] while hardware companies tend to have further distinguishing ...

  7. Negative (photography) - Wikipedia

    en.wikipedia.org/wiki/Negative_(photography)

    A positive image is a normal image. A negative image is a total inversion, in which light areas appear dark and vice versa. A negative color image is additionally color-reversed, [6] with red areas appearing cyan, greens appearing magenta, and blues appearing yellow, and vice versa.

  8. Microprinting - Wikipedia

    en.wikipedia.org/wiki/Microprinting

    Close-up of microprint incorporated on US$100 paper currency. Microprinting is the production of recognizable patterns or characters in a printed medium at a scale that typically requires magnification to read with the naked eye.

  9. Security printing - Wikipedia

    en.wikipedia.org/wiki/Security_printing

    Carefully created images can be hidden in the background or in a picture on a document. These images cannot be seen without the help of an inexpensive lens of a specific line screening. When placed over the location of the image and rotated the image becomes visible. If the document is photocopied the Halo image is lost.