File talk:Mars Viking 21i093.png

Why should other wiki editors trust that your own color-correction scheme, which you explain here, is more accurate than the color-correction done by NASA experts, which result in a more pinkish-looking sky as shown in the which you intend your image to be a replacement for? This seems like original research. I think that articles needing a picture of Mars should include the NASA version, not this blue-sky one, especially considering that your image might be seen as lending support to conspiracy theories (see here and here) which say that NASA is trying to cover up the true color of the Martian sky. Hypnosifl (talk) 17:17, 28 September 2012 (UTC)


 * Thanks for your comments.
 * I didn't make up the color scheme I used. There are several sources on the Internet that write how to get a the color scheme. I think I used: http://www.astrosurf.com/nunes/explor/explor_vik.htm. Maybe I should have mentioned the original source on the filters page in the first place, but I added it now, so future visitors don't get confused.
 * I'm not saying my scheme is "better" than NASAs, nor am I saying their scheme is incorrect. But on the other hand, their version isn't "better" than the ones I produced either. The "best" versions are, of course, the original source files, which I clearly listed in the Information section. So everyone can see the original source files and use them for whatever they see fit. I also clearly wrote that the image is "Own work based on images in the NASA Viking image archive". So the information I gave is fully transparent; I even wrote the process down of how to create the same file. It is just that both NASA and I used the same source files to create an image suitable for the web. That's all.
 * Let me state that I don't believe in any of those conspiracy theories. I notice that http://www.hiddenmars.com/Marsarchive/tabid/851/EntryId/7/Color-of-mars-2.aspx even uses my name, but I never knew they did. It's kind of sad.
 * So concluding why it is not original research: 1. I added the source to the filter page; I didn't make it up. 2. The source files are the original images, not the JPEG version of NASA, not the version I created.
 * Does this satisfy your question? Or do you have other concerns? Cheers, Van der Hoorn (talk • contribs) 18:26, 28 September 2012 (UTC)


 * Their scheme is presumably "better" if the objective is to produce something close to a true-color image that accurately represents the colors an astronaut would see if they were standing at the same location, looking through a clear helmet. You do mention in the description that yours is a false-color image, so I don't have an objection to the image + description itself, but in ordinary wiki articles wouldn't it make more sense to use true-color images when available, unless false-color ones specifically bring out interesting features that wouldn't be as apparent in a true-color image? Also, I think your description of the channel mixing process at User:Van_der_Hoorn/Viking/Filters (linked to on the page for the image) confuses the issue somewhat, because it makes the point that the original filters don't match the peak of human visions and then presents the process as "correcting" for that, saying at the end "Now your image should have the peak wavelengths in the last column of the table above, which matches the peak wavelengths of human vision quite closely." I think it would be good to add a disclaimer that this wouldn't be recognized by scientists as a very reliable way of producing something close to a true-color image--if you read the Discover letters page here, there's a letter titled "In Living Color" in which someone makes conspiratorial suggestions about how NASA processed the colors in Mars image, followed by a response from a scientist involved in NASA's image processing which indicates that you can't just apply uniform corrections to each of the three filtered images, instead you have to take into account the different properties of different surfaces (and air, presumably) to infer how each would radiate at peak human visual frequencies, given how they are observed to radiate at the three frequencies of the filters used. This scientist goes on to say "This work has been peer-reviewed and published in the Journal of Geophysical Research (Friedrich Huck and colleagues, 1977). Our approach and results have not been quantitatively challenged in the 27 years since." So, this would suggest that no photoshop technique based on uniform transformations to each of the three images can produce anything very close to what scientists would consider the best approximation to a true-color image. Hypnosifl (talk) 20:17, 28 September 2012 (UTC)


 * Also, this seems to be the 1977 paper the scientist above was referring to: Spectrophotometric and Color Estimates of the Viking Lander Sites. Hypnosifl (talk) 20:37, 1 October 2012 (UTC)