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Comment by bane | Hacker News Reader

And without the guards yelling "NO PHOTO!!!" every 10-20 seconds at people who dare to try to get a photo of the chapel that's not nearly as nice as this.

1 - http://mentalfloss.com/article/54641/reason-why-no-photograp...

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That's two reasons, not just copyright, and the millions of flashbulbs discharging there over the course of a short timespan would for sure have an effect on the lifespan of the work.

So that's a good thing for a bad reason and I totally sympathize with the position of the stewards of this amazing work.

I have a super nice story about this but I'm actually somewhat hesitant to tell it in detail in public, but I once discharged about a few 10's MW/m^2 of light concentrated on a very small part of a very famous painting.

How I got away with that will have to remain an untold story, but let's just say that my consultancy endeavours take me to interesting places and allow me to do interesting things.

I wish more places would specify "no flash photography" when that's really what they mean. I suppose some people don't know how to turn it off, but for those who do (or for those who don't bring a flash in the first place), it would be nice.

Most galleries I have been to lately have this policy now (obvious joke: 'but photos taken with rubbish cameras are fine...'), given the invention of cameras in everyone's phone its generally a lost battle to expect people won't take photos.

> I suppose some people don't know how to turn it off

I would argue that a majority of people either wilfully ignore this instruction or don't know how to do it.

Perhaps they should have a shared flikr account so that everybody could download good quality images of what is hanging on the walls

The best way I've seen it implemented was a museum that not only had a lengthy explanation about how to turn off your flash (including examples for Sony point-and-shoots, which were fairly popular), but also had a "test table" with similar light as you'd find inside, so experts could adjust their exposure/ISO accordingly.

Perhaps that's expecting too much from the average tourist, but still, I found it cool.

The table thing is very considerate of them. I wonder how many people use it?

At the Minneapolis Institute of Arts they're very clear about this, as is the Art Institute of Chicago and the Metropolitan Museum of Art, and I'm sure many others. Outside the U.S., I don't know.

Good to know! Sounds like it is in fact increasing as a policy.

That's two reasons, not just copyright, and the millions of flashbulbs discharging there over the course of a short timespan would for sure have an effect on the lifespan of the work.

Has anyone actually done the math on this? Or is it just a social hack used by museum guards to dodge the real reason for the policy, which is to keep the gift shop in business?

The biggest enemy of pigments is ultra-violet and lots of cheap flash kits do not filter that out.

Sunlight is about 1 KW/square meter on a non-cloudy day at noon, directly from above.

4% of that is a typical value for the UV component.

So the UV power hitting a 1 square meter surface at noon is about 40 Watts.

Photographic flash is on the order of a millisecond give or take, and power output of a typical flash during that millisecond is 100 Ws, or 100 KW/ms. Depending on how far away you are from the work of art you're putting for every 10 flashes then the equivalent of about of a second of exposure to the sun on the totality of the work (much more than 1 square meter, so you have to divide by the total surface). In the case of the chapel all the light discharged in the chapel will hit the object somewhere so apart from atmospheric effects (likely small) you can assume all of that light would contribute to the fading.

So every 10,000 tourists passing through and making one picture each with flash on is the equivalent of about 1000 second's worth of exposure to direct sunlight (think of a window of one square meter opening for 1000 seconds once per day), all this assuming that the flash contains an equivalent amount of UV as sunlight which likely is not the case. About 20,000 tourists per day pass through during the peak of the season, so on such days that's the equivalent of 2000 such seconds of the open window.

So at a guess, this is probably not too much of a problem, unless the pigments used break down very easily. (Blue is usually the most stable, with other pigments being more susceptible to fading)

What would be a problem is the fact that if all these people are discharging their flashes all the time that this seriously interferes with the ability of others who do not engage in such annoying reproductive behaviour to appreciate what they are looking at.

edit: fixed some of the math

It's worth mentioning that white LED flash has essentially zero UV.

This shows an LED light spectrum with one cool white LED. The warmer colors have even less of the 450nm peak.

http://saikoled.com/design.html#AAAAAAAAAAAAABAAA

(click on "Actual Brightness" to see the spectrum in mW instead of lumens, I didn't implement that in the URL header yet)

That's really a cool idea, is this your site?

Thank you, yes, it is my first and only foray into javascript. I found that it was consistently difficult to give people good visual ideas of what I'm talking about when I make claims like the one above. Particularly the lumens to watt conversion really helps people grasp better the idea of perceptual brightness, and also why when you're using fluorescent paints it's the power emitted instead of the lumens emitted that are important.

I haven't done the math, but seeing the chapels in Cappadocia, Turkey seems to prove this. Most of the chapels contain frescoes that are significantly color-faded, but Karanlık Kilise ("Dark Church"), which is quite dim and has very little ambient light, contains frescoes with far richer color. [1]

Unfortunately, the guards stationed there like to yell at tourists even if their flashes are off, so I suspect most people don't understand the reasoning.

[1] http://en.wikipedia.org/wiki/Churches_of_G%C3%B6reme

Pro tip: get in line sufficiently before closing time that you are guaranteed entry. Proceed through the first few rooms, then loiter. Move much slower than the horde of crowds flowing through the halls. Spend an hour looking through the early exhibits (I could spend a day in the room of tapestry maps alone), until the entrance is closed and the crowd thins. Make your way to the chapel and enjoy until they kick you out - I was in there for 15 minutes with just a few other people! (Albeit in October, not "peak" season).

I heard rumours they were considering closing the Sistine chapel to the public because people were using flashes when taking photos and it had the potential to damage the artwork.

I don't see why you would bother taking photos anyway. Go in and enjoy it. In a place so crowded your unlikely to get a good photo and there are plenty of photos already online for you to look at.

It's crowded, but you're looking up so the crowds aren't really that big of a problem.

This is what I remember as well. (1) It was very very crowded, and (2) the crowds didn't make a big impression in my memories of being there because I was looking up.

It's also annoying as hell being around a group of people interested in nothing more than documenting the fact that they're at said place, instead of actually just enjoying the moment.

There's hundreds of photos of the crap you're taking photos off. Just enjoy the moment and make it less touristy for everyone around you as well.

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