inside the Reach

There is an old saying, out of sight, out of mind. Sometimes there isn't wisdom in this...

I live in an area which is often rainy and humid (I think much of humanity does) and so mold and algae grows where it can (often where you don't want it). I often wonder about what grows inside things which are out of sight.

I have for some time seen small dark areas inside my reach tooth brush head when I bother to look in the small holes at the back. I don't like what I see ....

Today I broke open the toothbrush head to have a good look.

Here it is

As you can see there is quite an amount of stuff which is essentially green in there.

That is most likely mold, but it could be a kind of algae.

I often rinse it in mouthwash just to prevent it from having a perfect environment to live in, but perhaps molds are not effected by mouthwash? If its an algae these things can quickly form biofilms (which resist attacks from nasty chemicals that may kill the organism) so I wonder just how effective that is. Clearly it isn't very effective is it.

I also pathologically dry my toothbrush after use by spin drying it using a tool I made (don't ask). Yet still it harbors this within a month of use.

So while it may be out of sight, its not out of your mouth ;-)

I'm now wondering about leaving it immersed in a mouthwash solution when not in use ...

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PS: I am now going back to dropping my toothbrush head into alcohol. I'm using Gin at the moment, but OP Vodka could also do the trick. Metho will work but taste bad.

fungus and mold on CD's and lenses

for at least 3 of the last decades I've been aware of the issue of mold attacking the optical surface of things like lenses and CD's. I have been in the past involved with a few discussions, as well as published a little information about the topic on my blog (here).

The other night I pulled out a CD from my collection to play which had remained untouched there for some years (probably at least 10). While it was in its case, it had not been opened (although had been moved and even packed away in boxes while I was in Finland for a few years) and was in generally good condition.

The fungus I spotted (perhaps many would not have even spotted it) was so good a sample I just had to take this series of images to show you just what can grow on your lenses (and CD's) and why you should take seriously

You may just be able to see it as a small speck to the right of the pen cap clip.



getting in closer you can see it more clearly ... and what a classic specimine it is.



lastly a crop from the center of that image above showing the fungi "mycelium", and the fruiting body in the middle.


Aside from the fact that it's a speck on your lens you really should do something about this as they do actually etch into the glass surface (or plastic).

An excellent image of this can be found here and here where great examples of photographing the after effects of the mold on the surface of glass.



so my advice to you is that if you live in a humid climate (near the sea for instance) then to keep your valuable lenses in a dry container and perferably one which has been made humidity free.

As you will see (reading my above reference to my 2008 post) using silica gel is only patting yourself on the head and has no effect. Here is (reproduced) the graph of how the humidity went in a sealed container with some high grade indicating silica gel in the jar.


Figure 1: humidity measurements

Lastly don't leave your camera in its case; that is a sure fire way to get the best possible fungus infection you can (short of leaving it in the bathroom or in a damp room in the basment).

If you are interested in some more information on this subject, try reading this article of mine.

humidity and mold

By and large people in Northern Europe (and many parts of the USA) have totally no knowledge of how humidity and mold effects life in tropical and sub tropical areas. Of course for these people probably won't benefit much from this article but the point is that the views and understandings of things in the world is often shaped by these peoples. Queensland is an excellent example of why this is a problem. Here we have a population that acts and thinks as if its in Central Europe when it comes to many (if not most) things. Humidity is the cause of mold (or mould for the GB spelling), you can't blame the spoors because they're everywhere anywhere. So if you're trying to store or keep in good condition:

• paintings
• stamps
• prints
• camera equipment
• lenses and optical equipment
• down products

then you need to think about the humidity you store things in or you just have to accept that mold is going to get to it and destroy it sooner or later. Mold spores start to grow when the humidity goes over 60% and love it when it goes over 70% ... the more the happier it is in growing. You need to go below 40% to kill it. Beware that I extended storage at below 50% can begin to damage papers and oil based paint dyes (as well as oils in lubrication of camera parts which is my main concern). I can not recall my source of information on this, but other sources such as this one support my thoughts.

MOLD PREVENTION TIPS

• Keep the humidity level in your home between 40% and 60%. Use an air conditioner or a dehumidifier during humid months and in damp spaces, like basements.

In this part of the world in summer we seldom get that low. For example if you look at the BOM site for the Brisbane humidity: The graphs below come from this site earlier today. If you look at the Humidity graph you'll see it goes up and down daily: Perhaps you'll notice from the times (on the X axis) you'll that its at the driest time after lunch till nightfall. Actually it drops all day from dawn, especially on sunny days (like today was). There is a relationship between the significance of relative humidity and temperature .. the actual amounts of water in the air do not suddenly change (this is why its relative humidity not absolute humidity). So as the temperature of the air drops the amount of water which the air can hold reduces. This means that its closer to falling out of the air and becoming moisture. Paper (as well as dust collected on surfaces and wood) is a sponge for this sucking it up this now more available moisture. The way to see when things are likely to get dry and when they'll stay moist and damp can be seen when comparing the dew point (the point where water falls out of the air and starts forming on things) to the temperature. The closer the ambient temperature is to the dew point the the more things will start to feel 'damp'. You can see that as the temperature drops during the day that the dew point becomes closer in this graph: Temperature and Dew Point I've marked the worst point and the best point (for keeping things dry and mold free), its the wors time because the dew point is just 2 degrees C away from the ambient temperature. So the slightest cooling will start condensation forming. Unlike forming on a gold glass (if you live here you know what I mean) this is subtle, less obvious and not pooling on the table. Today the dew point is around 18 degrees C, while the ambient temp is 26 ... great for drying things outside (as your gut feeling would tell you anyway). Now we overlay the graphs upon each other we'll see that when the relative humidity (the blue line) is at its lowest which was (about 50%) we were at the point where the ambient air temp was higher. This is important because we try to keep our homes and rooms cooler ... note that the dew point has actually gone up a little ... so this means that if your stuff is kept in a cool place it will become more damp than the warmer sunny places. There are no cool dry places in our environment. How do you deal with this? People can delude themselves to the worth of desiccants like Silica Gel but the only real way to deal with this is to use a dehumidifier system or an Air Conditioner. Why won't desiccants work? Well for instance in my cabinet for my lenses (which is about 1000mm x 400mm x 400mm I'll pull 500ml of water out on a humid day. Yes that's right half a liter out of a sealed cabinet. I built a lens cabinet incorporating a dehumidifier for just my camera gear, but if you have more stuff I suggest putting it into a room that has a small window mounted AC unit. In fact this works out better in some ways as the benefit you'll get increases as the scale increases. The old "surface area to volume ratio" comes in to effect working in your favor. If you operate and AC or a dehumidifier it will consume energy. If you're interested in tuning the system so its not consuming energy (money) then your going to get your best effect turning it on just on dusk as the ambient air temperature starts to drop. You will suck out more of the moisture as the air temperature starts to cool with the least energy because its getting closer to the dew point and the AC will not need to drop its metal surfaces (where the moisture forms) in temperature so far. Remember AC and dehumidification requires energy ... the more you need to cool (or heat) something the more energy needed ... energy costs money. I use a simple device which has no fancy remote control system because I can plug it in via a clockwork timer and then forget about it. Hope that helps

humidity and cameras

Most people don't realise that Fungus grows on camera lenses. For example this page explains this a little. Fungus attacks camera lenses in storage, and its growth is related to humidity. So people who are a little more in the know often speak of removing humidity with Silica Gel. I've found this is not a sound practice for anything longer term than a few weeks. Given the regularity of this discussion I thought I'd put a blog entry here about it.

Background

If it remains below 50% then fungal spores will not germinate (as far as I've read). Keeping it below 30% risks dammage to your camera as the lubricants and foams will start to 'dry' ... yes, even salt crystals have water in their stucture and you can get anhydrous salt powder.

I lived in a semi tropical area, I had already lost a lens to fungus (a 50mm Zukio macro) from my Olympus from fungus (I often visit rainforest in the rain). I had started a business and bought some lenses worth quite some thousands of dollars (IE: TS-E 24, 90, and some large format lenses). I thought it prudent to conduct investigations.

I have a friend in the army who is a munitions specialist and he has reported to me that for their purposes silica gel was insufficient to maintain correct humidity. So wondering what this translated to in a quantitative manner I did the following experiment (if you google this on google groups this you'll find the results published back in the late 2000 on rec.photo):

Humidity Experiment with Silica Gel

Materials

• ~20g/100cc of Purple indicating silica gel
• heavy duty "zip seal" plastic bag (1 liter capacity)
• glass vegemite jar
• electronic hygrometer

Method

I thought I would test using a common zip seal bag, since cameras are often placed in these for protection. Since the camera in the bag occupies some space in the bag (and prevent the bag from being slim or vacuum sealed (if they indeed can be), I placed my sample of silica gel into a (lidless) glass jar with an electronic hygrometer hopefully replicating storing a 35mm camera lens in the bag.

The bag was only containing air from the room, no other gases were placed into the bag (such as gas from cylinder of nitrogen).

The bag was then zip sealed. The jar was put on its side, so that the top was not blocked further by the plastic and the hygrometer was visible with out disturbing the setup for making observations.

Note: The hygrometer displays LL% when out of range at the low end of humidity (which was cited as ~30%RH by the maker) and HH% when over 90%.
raw data

23-Mar-00 68% 6:38:00 PM experiment started
23-Mar-00 41% 8:52 PM
24-Mar-00 LL % {very rapid absorption depletion of humidity in bat}
25-Mar-00 LL% {already seems to be loosing the colour in the crystals, some are pink]
26-Mar-00 LL% {more of the crystals seem to be pale pink}
27-Mar-00 LL% {more of the crystals seem to be pale}
29-Mar-00 32% {most of the crystals are pink}
31-Mar-00 39% {more seem pale, a few are still dark}
02-Apr-00 43% {no apparent change in the crystals}
03-Apr-00 45%
04-Apr-00 45%
05-Apr-00 48%
06-Apr-00 50%
09-Apr-00 52%
10-Apr-00 52%
11-Apr-00 54%
13-Apr-00 57% {almost all crystals are depleted, about 9 remain as pale purple}
15-Apr-00 60%
17-Apr-00 64%
18-Apr-00 66%
24-Apr-00 64%
27-Apr-00 73%
29-Apr-00 76%
experiment concluded duration = 22 days.
graphically:


Figure 1: humidity measurements

Conslusion

As you can see, even in a small zip sealed bag the humidity rose to a point where the silica gel was failing to cope with humidity migration across the membrane of the plastic, and simply maintaining a constant level in the bags environment. Since silica gel can also release the humidity it then becomes a 'buffer' keeping the humidity reasonably constant (perfect for those fungii and molds) when the outside ambient humidity goes high. Typically this goes high in the night (as the air cools) and low in the day (as the air heats up).

Storing stuff inside your house (often cooler than outside) in a tropical area will ensure a nice humid atmosphere for your fungi. Meaning camera bags placed in cupboards are the worst locations.

Based on this I constructed my own humidity cabinet from a peliter effect device (commonly used in electric 'car fridge' systems) to condense the air and drain it out of the cabinet.


My power supply is a $15 cheapie 8 amp 12V car battery charger and a $20 12V GEL cell (to even it all out). I then ran a simple 24 hour timer circuit (like used to turn lamps on and off) to shut off the entire thing at different times of the day (used a relay to kick in on the 12V side of the car battery charger to shut off the power from battery to Peltier too). I made the back wall of the cabinet 5mm ply and cut out a shape to take the peltier in the middle. This puts one side of the heat sink inside (that'll be the cold side) and the other outside.

You'll need to fiddle with heat sinks to get the right efficiency, but I settled on this pair:
inside and outside

Then I made a simple catch tray (for the drips) out of a cut down plastic milk container and ran a bit of aquarium pipe out of the cabinet to drain it. Careful with this as in my summers I get about 500ml a day on a good humid day!

Naturally you need to be a bit handy, and have some electronics knowledge too. Of course you could buy one of the pre made ones.

hope this helps