I got vaguely fascinated by the documentary Tim's Vermeer a few years back, where Tim Jennison makes the argument that Vermeer used something not unlike a couple of these to project his scenes onto a canvas so he could effectively paint-by-numbers. Whether that's true or not, I found the idea fascinating, I just don't have a good enough understanding of optics to understand how the system of lenses and mirrors works to be able to know how to replicate it.
It's not really controversial or a secret IMO, a lot of historic ateliers taught students utilizing a camera obscura. Indeed basic education is still largely based around literal copying using grids, even today.
Yeah, it's the specific combination of a camera lucida, a concave mirror, and a long-focal-length lens that I just have a bit of difficulty figuring out. Like, I can put all the components together on the table, but knowing what the distances and angles need to be to get rid of parallax is not obvious to me.
It's kinda weird that the understanding of the word "spectrograph" seems to have changed a lot in not that long a time. My understanding is that work on observing the spectra of stars and understanding their composition went on in the 1920s. Not only did the 'spectro-' part acquire a relatively specific meaning, but it seems like the term flipped from naming a device to an image produced by a device in not that long a period.
I think, in this case, we are seeing semantic a relation between spectra of light (in terms of overlapping sets of frequencies) and producing a 'graph' of the spectrum of rotational frequencies in ink. Anyone know with any more certainty?
Traditionally, “X-graph” refers to the device which produces an “X-gram,” a physical record of some sort (e.g. telegraph/-gram, electrocardiograph/-gram, etc.)
I agree :) It seems like the artist/inventor may have at some point missed that finer linguistic point and attached instead to an alternative meaning of the word 'graph' :)
I didn't see mentioned the planimeter: "A planimeter, also known as a platometer, is a measuring instrument used to determine the area of an arbitrary two-dimensional shape." ~ https://en.wikipedia.org/wiki/Planimeter
> “The applications of the integraph are very numerous. With it we calculate areas, divide areas, determine centres of gravity, calculate moments of stability, load and resistance, solve algebraical equations, draw parabolas, etc.”
[0] http://blender3d.org.ua/book/BlenderArt1/img/g3.jpg
[1] https://developer.blender.org/p/zsoltst/
[2] http://web.archive.org/web/20060329091150/http://www.blender...
[3] http://web.archive.org/web/20070927020908/http://www.blender...