Final colour and contrast adjustments for the final image.ДЇigure 14: The difference between two stretch functions.

673n (Sulphur) shown in red in the final image), 2. First the individual exposure (taken through three different filters): 1. This is an example of a so-called false-colour image, where the blue was chosen for aesthetic reasons.ДЇigure 13: Sequences in the production of a Hubble Space Telescope image of Messier 17. Here the Hydrogen-alpha filter is coloured blue instead of the red colour it is in nature. and 3.) the resulting image (4.) is a colour composite.ДЇigure 12: An example of an enhanced colour image (not in chromatic order): Sometimes it is necessary to break the вЂrulesвЂ™ for image processing. Since the narrow-band exposures probe individual atomic transitions the result is an image that has very вЂsharpвЂ™ features.ДЇigure 9: A broad-band image of the вЂњHyperactive galaxy NGC 7673вЂќ.ДЇigure 10: An example of an image constructed from 7 broad-band filters all the way from ultraviolet (left) to infrared (right).ДЇigure 11: An example of how a colour image is constructed from four broad-band filters (seen from the side in 1.): blue, green yellow and red. The NвЂ™s and WвЂ™s are short for Narrow and Wide.ДЇigure 8: Example of an image constructed from narrow-band exposures. Column 5 contains the physical property of the radiati on the filter lets through. Filter names are to the left (names include approximate wavelength in nm) in column 1.

Courtesy .ДЇigure 7: Filter list for HubbleвЂ™s WFPC2 camera (Wide Field and Planetary Camera 2). The background is the CIE Chromaticity Diagram (representing the whole gamut of human colour perception). Courtesy of .ДЇigure 6: This illustration clearly shows the different gamuts of the RGB and CMYK colour spaces. In addition, the CMYK gamut is much smaller than the RGB gamut. Courtesy of .ДЇigure 5: The colours created by the subtractive model of CMYK don't look exactly like the colours created in the additive model of RGB Most importantly, CMYK cannot reproduce the brightness of RGB colours. Red, green, and blue are the primary stimuli for human colour perception and are the primary additive colours. Such an image may contain up 16 million different colours.ДЇigure 4: the additive model of RGB. The possible range of the pixel values depend on the colour depth of the image, here 8 bit = 256 tones or greyscales.ДЇigure 3: A true-colour image assembled from three greyscale images coloured red, green and blue. For more inforamation, visit FITS Liberator 4 page at NOIRLab.ДЇigure 1: An image - an array or a matrix of pixels arranged in columns and rows.ДЇigure 2: Each pixel has a value from 0 (black) to 255 (white). The NOIRLab/IPAC/ESA/STScI/CfA FITS Liberator 4 is available.

The Longest Day Colorized Download