by alanfgag » Tue May 06, 2014 6:00 pm
Greetings and thanks for the discussion of my image featured in today's APOD. The "normal" tonality image linked above is a good illustration of two possible variations in processing the same data - but it is an APOD dating from 2011.
http://www.avertedimagination.com/img_p ... rvana.html
The full resolution version of today's APOD can be seen here:
http://www.avertedimagination.com/img_p ... ersun.html
The hues in this image are not inverted, but subjectively colorized. All the details are captured in the hydrogen alpha wavelength. This could be portrayed by colorizing the image completely in the deep red, but the result would be flat as the eyes are not very sensitive to perceiving subtle detail in red. The tonality of the disk is inverted, which makes the sunspots light, the hot active regions dark and gives enhance contrast to the filaments and certain other structures of the chromosphere. Having the limb brighten towards the edge rather than darken provides, to my eye, a smoother transition to the edge prominences. To me, this portrayal is closer to what I experience with my eyes - which are amazing in their ability to perceive a much larger dynamic range than an image can display on a computer screen. I realize that some do not like the inverted details. In the end, it is an aesthetic decision of the photographer to show the sun in this context. With many cameras pointed at our star, including SDO and SOHO, we have an amazing library of solar images at our fingertips. I appreciate Robert and Jerry sharing mine with you and also hearing your comments.
Greetings and thanks for the discussion of my image featured in today's APOD. The "normal" tonality image linked above is a good illustration of two possible variations in processing the same data - but it is an APOD dating from 2011. [url]http://www.avertedimagination.com/img_pages/solar_nirvana.html[/url]
The full resolution version of today's APOD can be seen here: http://www.avertedimagination.com/img_pages/eastersun.html
The hues in this image are not inverted, but subjectively colorized. All the details are captured in the hydrogen alpha wavelength. This could be portrayed by colorizing the image completely in the deep red, but the result would be flat as the eyes are not very sensitive to perceiving subtle detail in red. The tonality of the disk is inverted, which makes the sunspots light, the hot active regions dark and gives enhance contrast to the filaments and certain other structures of the chromosphere. Having the limb brighten towards the edge rather than darken provides, to my eye, a smoother transition to the edge prominences. To me, this portrayal is closer to what I experience with my eyes - which are amazing in their ability to perceive a much larger dynamic range than an image can display on a computer screen. I realize that some do not like the inverted details. In the end, it is an aesthetic decision of the photographer to show the sun in this context. With many cameras pointed at our star, including SDO and SOHO, we have an amazing library of solar images at our fingertips. I appreciate Robert and Jerry sharing mine with you and also hearing your comments.