Talk:Shadowgraph

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The image on the right of the page features 4 different example of shadowgraphs. Only in a recent NYT article they use 2 of those examples as examples of Schlieren photography. Idk enough about the methods so I can't say if wikipedia or the NYT are wrong or not.

 —Preceding unsigned comment added by 94.194.61.166 (talk) 00:43, 13 August 2009 (UTC)[reply]

Is there someone in the know to distinguish between shadowgraph and Absorption imaging? It seems to me it is the same, but I would like to know for sure.

I try: The main difference is that the shadowgraph image comes out because of coherent superposition of the main undisturbed beam together with the tiny diffracted ones. In this sense the image is rather different from a simple shadow of the sample. The shadowgraph is sensitive to refractive index differences within the sample, while absorption is sensitive to absorption differences within it. If you have a slab of water, divided by a membrane, and half of the water is salted, the shadowgraph can show you the difference, while the absorption imaging is not. If, on the contrary half of the water is filled with a little bit of ink, the shadowgraph is not able to detect differences, while the absorption imaging is. —Preceding unsigned comment added by 193.55.218.109 (talk) 14:35, 4 March 2010 (UTC)[reply]

Sorry, but I find it totally appalling that there is not even a reference to the "Shadowgraph" optical comparator on this page. I understand that this is a listing for physics - however the Shadowgraph is a common tool in many machine shops (even University Physics Department machine shops). Simply Google "used shadowgraph". At the least there should be a "see also" to optical comparator. I venture to guess that more people understand a "shadowgraph" to be a shop tool rather than a graphical representation. —Preceding unsigned comment added by 68.20.4.127 (talk) 14:03, 27 March 2011 (UTC)[reply]