What's canned in the air debacle? ;-)
On a serious note, - let me share my experience.
In my 20+ years of working with small high-purity samples and devices,
we've been always trying to avoid using compressed air cans for cleaning
the samples. The proper way has always been to use compressed clean
nitrogen (it is usually cleaner than the compressed air, because that
nitrogen was either from a high-purity cylinders or a boil-off from the
liquid nitrogen tank).
"Cleaning" cans tend to carry particles of the gas, and those leave
residue. Those are most apparent on the first blow after a break, - you
can see liquid droplets spat from the nozzle.
Actually, if you must use these cans, - the suggestion is to point the
first big "spray" away from whatever you are cleaning.
In the past few years, due to the lack of proper infrastructure in some
labs that my students and I had to use, we occasionally used the aerosol
cans when nothing else was available.
I can see the residue on the surface of the samples afterwards.
I also know that there are different cans with different "ingredients", -
some are not as bad as others.
HTH,
Igor
PS. The snowflakes are great, as always!
Alan C Fri, 09 Jan 2015 06:35:21 -0800 wrote:
Most irritating. I would imagine that most aerosols are prone to
delivering some gunge especially when nearly depleted. What would work
well is a mini lab. bench compressor with a decent filter on the outlet
but it would hardly be cost effective.
Alan C
-----Original Message----- From: Mark C
Sent: Friday, January 09, 2015 7:34 AM
To: Pentax-Discuss Mail List
Subject: Canned Air Debacle
Last summer I managed to get a lot of dust and crude on the view screen
of my K-3, so I wound up giving it a good cleaning with canned air. A
lot of the stuff went onto the sensor, so I blasted it as well without
thinking about it. Lo and behold, everything came out nice and clean. I
had always been skeptical about using canned air on a sensor, but after
this experience I figured that it was OK after all.
SO, today before going out to take snow flake photos I gave the K-01
sensor a good blast with a canned air. Looking at my first results - the
photos were incredibly spotty and speckled. At first I thought the glass
I shoot the crystals on was dirty, but then I noticed a few distinctive
spots and speckles that were on each and every frame. So I tested the
sensor for dust by putting on a 90mm macro lens, stopping down to f32,
and placing the camera face down on a light table.
Here's one of the snowflake shots that alerted me to the issue and the
sensor test on the light table:
http://www.markcassino.com/b2evolution/index.php/imgp8714-jpg-1?blog=9
Click the images for a larger file.
I always figured that the problem with canned air would be that it would
burp up propellant onto the sensor - but in this case the issue is
apparently droplets of oil or something like that. Also - I have used
this can to "clean" several rolls of film before scanning. Maybe I
should go back and look for the spots because I never noticed them. My
guess is that the film grain hides any spots that appear.
I had a few old sensor swabs and a bottle of Eclipse E2 fluid here and
was able able to get the sensor cleaned up just fine. It has been years
since I did a wet cleaning of a camera sensor. The can of air I used
today was 3M, in the past I had used Office Depot's store brand (which
is what worked fine on the K-3 sensor). Since the canned air has worked
fine int he past, I guess it is simply a difference in quality between
brands or maybe I just held the can at the wrong angle today. At any
rate - I am not using canned air on sensors any more!
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