6 ms·

UV light and mildew: why physical objects degrade over time

53 points by Amorymeltzer 5y ago

oleganza 5y ago
Surprised to not find a mention of the second law of thermodynamics in the article.
- throwawaylinux 5y ago
  Seems like it was intended to be a simple and practical list of things that can be avoided or improved to reduce the process, rather than explaining the physics behind it. But now that you mention it, this would be a nice opportunity for you to explain how thermodynamics applies to degradation of these kinds of materials mentioned.
- kadoban 5y ago
  I'm not sure the second law really applies, these aren't closed systems (the Sun shining on them being the most obvious input).
  - oleganza 5y ago
    Yes, that's true. Thanks for correcting me.
ClumsyPilot 5y ago
"But digital photos, while not nearly as high a resolution as a modern pro-quality camera can take, do not age themselves quite so quickly." This is a bit of a side-track, but most families have an archive of physical photos dating back decades, you put them in an album, and 50 years later they will still be there. Meanwhile every family I know has decade of digital photography that was lost to broken hard-drives and corroded CD's. The only way to preserve digital information is to constantly babysit it, making sure you have two/three copies and replacing the broken disks (or outsource the process to Dropbox/Onedrive/whatever). There is no consumer-friendly process of archiving things - you can try burning it to optical, but will there be a drive to read it in 50 years? No-one I know still has an optical drive, and that's if they last.
- stickfigure 5y ago
  I know multiple people whose homes burned down. Physical copies are quite vulnerable to loss.
- cheschire 5y ago
  You just skipped over all the solutions to the digital problems and ignored the vulnerabilities inherent in single physical copies such as damage or loss. I get the feeling you’ve made up your mind already.
  - ClumsyPilot 5y ago
    "You just skipped over all the solutions to the digital problems" I am all ears, please tell me which solution I could recommend to my aging parents except "pay dropbox"?
    - rndmind 5y ago
      You seem like you already have your mind made up, and you already know what people are going to suggest ahead of time! I wish I could predict the future like that . . . As others have pointed out, m-disks will preserve your data hundreds of years, but I personally use a RAID array. Of course in 50 years there will still be dvd readers, don't be overly alarmist.
      - woodruffw 5y ago
        > As others have pointed out, m-disks will preserve your data hundreds of years, but I personally use a RAID array. Maybe it's lack of experience, but I've never actually seen an M-Disc in the wild. I get the impression that you can't use a normal disk burner to write them, so expecting the world's Joe Schmoes to use them (much less maintain a RAID array) feels unrealistic. By contrast, just about everybody knows how to put photo prints in a physical album.
        hypertele-Xii 5y ago
derbOac 5y ago
This is funny to me because I've had discussions surrounding the thesis of the title with my in-laws, about building materials. Vinyl lumber is great for areas prone to excessive shade and moisture, because it's so resistant to rot. Put it in full sun though, and it eventually turns to plastic powder. Some lumber is the opposite, though: it's difficult to maintain in wet shade because it gets destroyed by fungi and moss; put it in the sun, though, and take care of it, and it can last for a long time. It's interesting to me UV light and rot are coming up in a totally different context, as it points to the importance of these two types of decay phenomena. The other, of course, is physical force, in the form of wind or physical impact. But in the absence of that the two great destroyers are microbes and radiation.
- lmm 5y ago
  > Some lumber is the opposite, though: it's difficult to maintain in wet shade because it gets destroyed by fungi and moss; put it in the sun, though, and take care of it, and it can last for a long time. I wonder if that's partly because the same UV that would damage the vinyl is killing off the microbes.
Daniel_sk 5y ago
Most plastics will get brittle over long time, at least the older production ones (modern plastics have better plasticisers) even when kept in good conditions. Exposing it to UV light will make the process faster. But even O2 exposure will oxidise it over time. Rubber will also dissipate over time and get brittle and crumble. All of this is usually fine from a perspective of a humans average lifespan, but a lot of artefacts from this age will not be preserved.
cesaref 5y ago
It's an interesting subject, and i've some experience of photographic preservation having printed in darkrooms for 20 years or so. When considering archiving old photographs, there's quite a bit of difference between colour and B&W prints, and also colour and B&W negatives. The B&W prints and negatives contain silver, which is what makes the dark spots on the print and negatives, and it's presence stops microbes attacking the material. For colour prints and negatives, the silver that was originally present in the material is removed with a bleach stage when processing (with a dye being activated to produce the colours you see) so you need to use some other method to protect the material from microbes. I think modern colour film stock includes a stabilizer, whilst older processing used Formaldehyde.
ggm 5y ago
Life in the sub tropics is this. Modern books crumble. Old books fox. All books are eaten by roaches.
lordnacho 5y ago
What's fascinating is my own sense of time has been somewhat frozen by the advent of digital technology. I'd grown up watching old clips of Pele, Carlos Alberto or Tardelli, then Maradona. They looked a certain way by the time I was 20. Then around the mid-2000s, everything went digital and soon HD as well. You can watch the 2006 World Cup and think it was happening live. The style of shorts has also more or less frozen, so it's not as easy as looking at 80s-style super short shorts to guess the year. Same goes with photos. My parents died and I got the family album. You can tell the different colors diffuse at different rates. Shots from the 70s look a different way to ones from the 80s and 90s. With my kids, everything is digital. I have pics of them from almost every day, and they look just the same. I think the fading process is actually faster than we think, as even those pics of the family from the 80s looked kinda old by the mid 90s.

53 points by Amorymeltzer 5y ago

oleganza 5y ago

Surprised to not find a mention of the second law of thermodynamics in the article.

throwawaylinux 5y ago
Seems like it was intended to be a simple and practical list of things that can be avoided or improved to reduce the process, rather than explaining the physics behind it. But now that you mention it, this would be a nice opportunity for you to explain how thermodynamics applies to degradation of these kinds of materials mentioned.
kadoban 5y ago
I'm not sure the second law really applies, these aren't closed systems (the Sun shining on them being the most obvious input).
- oleganza 5y ago
  Yes, that's true. Thanks for correcting me.

ClumsyPilot 5y ago

"But digital photos, while not nearly as high a resolution as a modern pro-quality camera can take, do not age themselves quite so quickly." This is a bit of a side-track, but most families have an archive of physical photos dating back decades, you put them in an album, and 50 years later they will still be there. Meanwhile every family I know has decade of digital photography that was lost to broken hard-drives and corroded CD's. The only way to preserve digital information is to constantly babysit it, making sure you have two/three copies and replacing the broken disks (or outsource the process to Dropbox/Onedrive/whatever). There is no consumer-friendly process of archiving things - you can try burning it to optical, but will there be a drive to read it in 50 years? No-one I know still has an optical drive, and that's if they last.

stickfigure 5y ago
I know multiple people whose homes burned down. Physical copies are quite vulnerable to loss.
cheschire 5y ago
You just skipped over all the solutions to the digital problems and ignored the vulnerabilities inherent in single physical copies such as damage or loss. I get the feeling you’ve made up your mind already.
- ClumsyPilot 5y ago
  "You just skipped over all the solutions to the digital problems" I am all ears, please tell me which solution I could recommend to my aging parents except "pay dropbox"?
  - rndmind 5y ago
    You seem like you already have your mind made up, and you already know what people are going to suggest ahead of time! I wish I could predict the future like that . . . As others have pointed out, m-disks will preserve your data hundreds of years, but I personally use a RAID array. Of course in 50 years there will still be dvd readers, don't be overly alarmist.
    - woodruffw 5y ago
      > As others have pointed out, m-disks will preserve your data hundreds of years, but I personally use a RAID array. Maybe it's lack of experience, but I've never actually seen an M-Disc in the wild. I get the impression that you can't use a normal disk burner to write them, so expecting the world's Joe Schmoes to use them (much less maintain a RAID array) feels unrealistic. By contrast, just about everybody knows how to put photo prints in a physical album.
      - hypertele-Xii 5y ago

derbOac 5y ago

This is funny to me because I've had discussions surrounding the thesis of the title with my in-laws, about building materials. Vinyl lumber is great for areas prone to excessive shade and moisture, because it's so resistant to rot. Put it in full sun though, and it eventually turns to plastic powder. Some lumber is the opposite, though: it's difficult to maintain in wet shade because it gets destroyed by fungi and moss; put it in the sun, though, and take care of it, and it can last for a long time. It's interesting to me UV light and rot are coming up in a totally different context, as it points to the importance of these two types of decay phenomena. The other, of course, is physical force, in the form of wind or physical impact. But in the absence of that the two great destroyers are microbes and radiation.

lmm 5y ago
> Some lumber is the opposite, though: it's difficult to maintain in wet shade because it gets destroyed by fungi and moss; put it in the sun, though, and take care of it, and it can last for a long time. I wonder if that's partly because the same UV that would damage the vinyl is killing off the microbes.

Daniel_sk 5y ago

Most plastics will get brittle over long time, at least the older production ones (modern plastics have better plasticisers) even when kept in good conditions. Exposing it to UV light will make the process faster. But even O2 exposure will oxidise it over time. Rubber will also dissipate over time and get brittle and crumble. All of this is usually fine from a perspective of a humans average lifespan, but a lot of artefacts from this age will not be preserved.

cesaref 5y ago

It's an interesting subject, and i've some experience of photographic preservation having printed in darkrooms for 20 years or so. When considering archiving old photographs, there's quite a bit of difference between colour and B&W prints, and also colour and B&W negatives. The B&W prints and negatives contain silver, which is what makes the dark spots on the print and negatives, and it's presence stops microbes attacking the material. For colour prints and negatives, the silver that was originally present in the material is removed with a bleach stage when processing (with a dye being activated to produce the colours you see) so you need to use some other method to protect the material from microbes. I think modern colour film stock includes a stabilizer, whilst older processing used Formaldehyde.

ggm 5y ago

Life in the sub tropics is this. Modern books crumble. Old books fox. All books are eaten by roaches.

lordnacho 5y ago

What's fascinating is my own sense of time has been somewhat frozen by the advent of digital technology. I'd grown up watching old clips of Pele, Carlos Alberto or Tardelli, then Maradona. They looked a certain way by the time I was 20. Then around the mid-2000s, everything went digital and soon HD as well. You can watch the 2006 World Cup and think it was happening live. The style of shorts has also more or less frozen, so it's not as easy as looking at 80s-style super short shorts to guess the year. Same goes with photos. My parents died and I got the family album. You can tell the different colors diffuse at different rates. Shots from the 70s look a different way to ones from the 80s and 90s. With my kids, everything is digital. I have pics of them from almost every day, and they look just the same. I think the fading process is actually faster than we think, as even those pics of the family from the 80s looked kinda old by the mid 90s.