VWR Gel Documentation Imager2 Instruction Manual page 43

The Histogram button
again cancels the Histogram function.
The histogram is a graph showing the number of pixels in the image at each different intensity value found
in that image. For a 16-bit image there are a possible 65535 different intensities so the histogram will
graphically display 256 numbers showing the distribution of pixels amongst those grayscale values. If the
graph is bunched up to the left it indicates that not many grayscale levels have been captured and the red
lines on the histogram graph may need to be adjusted to see bands. If the graph reaches to the far right
(65535 grayscales) this indicates that the image may be saturated.
IMAGE SLIDER CONTROLS
The following controls are available to adjust the way a captured image looks.
Digital Zoom slider
Image Inversion button
The Digital Zoom slider allows you to zoom in or out of the displayed image. Dragging the slider towards
the + sign zooms in, dragging the slider towards the - sign zooms out.
The Gamma slider changes the tone of the overall image. With reference to the histogram mentioned
previously, the Gamma function changes the relative brightness of the recorded midrange tones by shifting
them either towards the dark end or the white end of the graph, without changing the extreme dark or
extreme white values. This gives the recorded image an overall darker or lighter appearance.
Contrast is a measure of how bright highlights are in an image. Brightness is a measure of how bright
shadows are in an image. Use the Contrast slider to control how bright the lightest objects in an image are
displayed. Use the Brightness slider to control how bright dark objects in an image are displayed.
If you make changes using the sliders you can undo the changes by selecting the Reset icon.
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HISTOGRAM DISPLAY
turns red to indicate that the function has been selected. Selecting the button
Reset button
IMAGE SLIDER CONTROLS
Instruction manual VWR
Gamma slider
Contrast / Brightness
sliders
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Imager2