Is color SEM (Scanning electron microscopy) possible?

SEM is only capable of producing black and white images. The color you see in the image above, and any image that purports to be a “color SEM” is a fake. The color is artificial, and was added later as a result of a program or simply adobe photoshop. SEM works by simply firing electrons onto an object, and then detecting the secondary electrons that are ejected from the object. Future SEM may possibly have color through taking energy distributions of ejected electrons from known materials into account.

Another fact that is not well known among the public at large is that the insects you see in SEM pictures are not alive. They have to be carefully prepared by adding a conductive layer of metal through sputtering, and removing all moisture. Sometimes the insects are even frozen in preparation for SEM.

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3 Responses to Is color SEM (Scanning electron microscopy) possible?

  1. Amber Lauer says:

    Due to the necessary vacuum conditions, no specimen in SEM is alive, insect or otherwise. It is not true, however, that all samples are coated. Coating reduces ghostly effects in imaging and destruction of a sample, but sometimes better images are collected without coating.

  2. Frank says:

    the image above, and any image that purports to be a “color SEM” is a fake.

    This statement is true regard this image. But not in general. Additionally to the electron signal (electron images) X-rays come from specimen. These X-rays contain element information. Therefore the basic idea of ColorSEM is colorizing the b/w electron images with these real additional information. This is same es with visual light, the color contains something from chemistry of the object.

    That’s why ‘any image that purports to be a “color SEM” is a fake’ is definitely wrong.

  3. GAlcidesS says:

    As far as I know, SEM images are colorless. The definition of color as a wave within a spectrum (the visible light spectrum) depends on the wave characteristics. Since SEM images are obtained from information gathered of electron beans and not light, this electron wavelength has no color information at all, that’s why all SEM images with color had to be post-modified with a software for color addition.

    An additional comment: not all the samples for SEM are necessary dead or gold coated. LVSEM, LTSEM (Low Vacum SEM and Low Temperature SEM, respectively) are available and the samples do not need any coating. There is also a ESEM (Environmental SEM) which requires no or little sample preparation. Living samples could be also analyzed in some SEM models.

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