Boundaries

A morning digression.

When one makes images on paper with a pencil one is apt to draw outlines. As a beginner, that is likely all that one does. If one is not a beginner, perhaps something like the snap above (from reference 1).

Or if one is making an image on a wood block with a burin. At least, if you are an engraver who follows in the steps of Eric Gill.

But the real world, on the whole, is not like that. If you view an object, there is a point of view and the boundary of the object as seen from that point of view, is unlikely to have a marked boundary. You just have one mass of colour meeting another mass of colour, perhaps in something approximating to a straight line, in the way of the snap above, lifted from reference 2.

But there are exceptions. A picture on the wall, a rather special sort of object, is likely to be framed by a frame, although there is something of a fashion these days for frame-free presentation.

Another, illustrated by the snap at the top of this post, is where the lighting and the object combine to produce more or less black boundaries on white. Where incident light is trapped in some crack or crevice, which thus appears black.

Yet another, my starting point, is where the light is behind some material which does not have a sharply defined surface, say a cotton sheet rather than a slab of smooth but matt stone. In the latter case, one just gets two masses of colour meeting, without a boundary. But in the former case, you may get a white boundary between two darker masses. Somehow, enough light is getting trapped on the surface so that when viewed tangentially, as it is at a boundary, that boundary appears as a white line.

I have not been able to make my own image of this effect, but Holman Hunt clearly knew all about it. As can be seen, for example, on the top boundaries of some of the sheep and in the glow around the cliff dropping down to the left.

Will I be prompted to take a proper look at reference 4, picked up from somewhere years ago, and not much looked at since?

Is this something that the creationists of Epsom get into, or are they too busy with their big power tools being conceptual? I don't suppose that this is a matter on which reference 5 would be helpful.

[The CMS experiment at the Large Hadron Collider. Credit: Piotr Traczyk/CERN]

PS: not relevant here, but interested to read over breakfast, in yesterday's Observer, about the upcoming collider battle, for which see reference 6. And for some old news see reference 7. Is it just the CERN people wanting to build their empire, or is it really worth taking out the particle physics budget for the next half century? Has the large hadron collider (LHC) done well enough for it to be right to throw a lot of money at more of the same? How on earth will Leader Starmer come to decide how to cast his vote, assuming that is, that he has one?

I guess delegation has to be the answer, with the Leader usually just ticking through whatever recommendation eventually emerges. Hopefully the delegates will not have arrived in Downing Street with too many of their own axes to grind.

References

Reference 1: https://psmv4.blogspot.com/search?q=gill.

Reference 2: https://psmv5.blogspot.com/search?q=mondrian.

Reference 3: https://www.tate.org.uk/art/artworks/hunt-our-english-coasts-1852-strayed-sheep-n05665.

Reference 4: The elements of drawing - John Ruskin - 1857.

Reference 5: https://www.uca.ac.uk/campuses/epsom/.

Reference 6: The biggest machine in science: inside the fight to build the next giant particle collider: The European physics laboratory CERN is planning to build a mega collider by 2070. Critics say the plan could lead to its ruin - Davide Castelvecchi, Nature - 2025.

Reference 7: https://psmv4.blogspot.com/2019/03/the-next-supercollider.html.