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Wednesday, 12 February 2014


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The next time someone proclaims that it's only the pictures that matter, we can use the success (i am assuming) of this sale as a great counterpoint. Process matters!

There certainly are matching-related optimization problems that are NP-complete. Usually it involves adding some kind of weighting or cost to the matches and then requiring that you minimize this cost.

The matching of medical residents to residencies is one example of this if I recall correctly.

The images on ctein's website aren't appearing. Is there anywhere else I could see the images to choose from?

The pathological extremes

Which TOP readers did you have in mind ?


I find the optimization aspect of this whole thing fascinating. (Of course, I would.) It reminds me very much of a simpler version the inheritance optimization procedure from Neal Stephenson's "Cryptonomicon." Given Ctein's known genre affections, I have some small suspicion that the resemblance isn't entirely coincidental.

I'm guessing Jim Marshall's John Coltrane images aren't part of this deal...

The problem you're trying to solve is not NP-complete; it's called the "Stable Marriage Problem": http://en.wikipedia.org/wiki/Stable_marriage_problem

Dear Nick,

Do the usual: clear your browser cache and reload this TOP page. The link should direct you to http://ctein.com/topmatrix.htm and you should see the images of the photographs just fine.

If your difficulties persist, this is beyond my expertise to resolve; all I can tell you then is that it's a problem with your system, not with the webpage.


Dear Nigel,

Since all readers are above average at Lake Waukesha, the pathological individuals are probably the normal ones.


Dear Nicholas,

I have not read Cryptonomicon, so any resemblance is entirely coincidental.


Dear k...,

I don't own the rights to any photographs that I've printed for other people. I have lots of matrix sets for photographs I've printed for other photographers, but those are not mine to sell, because I don't have authorization to do so. Those photographers get to establish their own markets for their work.

I would have no interest in even making such an inquiry. By the time I got done splitting the money between them, me, and Mike, it wouldn't be worth my time or effort.

pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
-- Ctein's Online Gallery http://ctein.com 
-- Digital Restorations http://photo-repair.com 

I don't think this is the stable marriage (as the preferences only go in one direction -- the prints don't care about the buyer but the buyer cares about the prints) or the hospital/residents problem (you don't care about the residents specialty i.e. the buyers preference. IRL those end up in the "Scramble") but rather a simpler assignment problem as N people have to get N items.


As the weights are all binary on three things you might apply the Hugarian Algorithm which is polynomial (P not NP :-) ).



What are your plans for the unsold matrices?

"Some are no-brainers to me, but there are a few real surprises, including one photograph that gets no traction in my portfolio but has four requests already for the matrix set. What this says is that TOP readers have broad and eclectic tastes."

After sorting through your portfolio, the photos I selected are probably not my overall favorite photographs in your portfolio. Instead, I selected photographs which I thought might be most interesting when presented with the matrices, each as a piece of art itself (though I admit, my limited knowledge of the details of dye transfer may negate these efforts). Had I been shopping for prints, only 1 of my selections would have been in my top choices.

Dear John,

About half the sets are unsold, and those I'll offer on my website. The selection page is up already:


but I haven't coded in the explanatory or ordering information.

Customers will be able to pick and choose among those as they like, but they'll be paying a considerably higher price (probably $275 plus shipping), in keeping with the philosophy of sales on Mike's site. If educational institutions or museums contact me about acquiring sets, I'll cut them a much better deal. Or individuals buying in bulk––prior to last week's sale, one conservator bought 30 sets to use in his classes.


Dear Scotto,

People will take more “risks” when they're looking at a price in three figures instead of four, so I expected a considerably broader range of selections than what people usually buy. But still, “Smiley Seal,” which isn't remotely typical of my work and never gets any interest in my portfolio, got five requests. That's way, way above average; in fact, only 15 sets got more requests than that.

pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
-- Ctein's Online Gallery http://ctein.com 
-- Digital Restorations http://photo-repair.com 

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