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DIY light source for 10X10" enlarger.
DIY light source for 10X10" enlarger.
To date I've considered enlarger light sources to be engineering well beyond
my feeble capability, but I have used and examined only condenser enlargers
such as the Leitz IIa and Omega condenser enlarger, but my task now is to
make a diffusion thpe for the 10x10 enlarger.
I want something with No built-in filtration. No fancy color mixing for VC
papers. No electronics. No side-lit mixing chambers. Just a straight forward
light source and a diffusing layer. I question cold light, mercury vapor,
tubes, whatever they are because I just don't plain understand 'em.
I can blunder head-first into this project, but this group has some smart
people with impressive experience, so I'll put my blunder idea forward.
First, I am limited to ~110V AC power although converting to DC is an
option. How about a simple array of 'white' LEDs at the top, pointing down
over the typical sheet of plastic translucent material found in home supply
places? Or should it be fine ground glass? I am not concerned about the
variability of LEDs over time unless they change during the time it takes to
get an 8X10 negative-to-print just right - maybe a day or two. The power for
the light will be run through a robust power-conditioner once set aside for
a big minicomputer. Batteries not included.
So far so good? Corrections would be most welcome. OR just let me blunder
and if it goes badly I'll post pictures of the catastrophe.
To date I've considered enlarger light sources to be engineering well beyond
my feeble capability, but I have used and examined only condenser enlargers
such as the Leitz IIa and Omega condenser enlarger, but my task now is to
make a diffusion thpe for the 10x10 enlarger.
I want something with No built-in filtration. No fancy color mixing for VC
papers. No electronics. No side-lit mixing chambers. Just a straight forward
light source and a diffusing layer. I question cold light, mercury vapor,
tubes, whatever they are because I just don't plain understand 'em.
I can blunder head-first into this project, but this group has some smart
people with impressive experience, so I'll put my blunder idea forward.
First, I am limited to ~110V AC power although converting to DC is an
option. How about a simple array of 'white' LEDs at the top, pointing down
over the typical sheet of plastic translucent material found in home supply
places? Or should it be fine ground glass? I am not concerned about the
variability of LEDs over time unless they change during the time it takes to
get an 8X10 negative-to-print just right - maybe a day or two. The power for
the light will be run through a robust power-conditioner once set aside for
a big minicomputer. Batteries not included.
So far so good? Corrections would be most welcome. OR just let me blunder
and if it goes badly I'll post pictures of the catastrophe.
Re: DIY light source for 10X10" enlarger.
In article <R7SdnU6pz7oHcGHanZ2dnUVZ_quhnZ2d@supernews,com >,
jjs <nobody@nowhere,net > wrote:
>To date I've considered enlarger light sources to be engineering well beyond
>my feeble capability, but I have used and examined only condenser enlargers
>such as the Leitz IIa and Omega condenser enlarger, but my task now is to
>make a diffusion thpe for the 10x10 enlarger.
>
>I want something with No built-in filtration. No fancy color mixing for VC
>papers. No electronics. No side-lit mixing chambers. Just a straight forward
>light source and a diffusing layer. I question cold light, mercury vapor,
>tubes, whatever they are because I just don't plain understand 'em.
A fluorescent light source of some kind -- a "cold light" source -- will
give you the most light for the least power (and heat) unless you really
want to use a *lot* of white LEDs. I'm not sure you can get enough output
from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
times with a 10x10 negative, and I am also skeptical that it will be as
even as you'd get with an array of fluorescent tubes.
--
Thor Lancelot Simon tls@rek.tjls,com
"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky
In article <R7SdnU6pz7oHcGHanZ2dnUVZ_quhnZ2d@supernews,com >,
jjs <nobody@nowhere,net > wrote:
>To date I've considered enlarger light sources to be engineering well beyond
>my feeble capability, but I have used and examined only condenser enlargers
>such as the Leitz IIa and Omega condenser enlarger, but my task now is to
>make a diffusion thpe for the 10x10 enlarger.
>
>I want something with No built-in filtration. No fancy color mixing for VC
>papers. No electronics. No side-lit mixing chambers. Just a straight forward
>light source and a diffusing layer. I question cold light, mercury vapor,
>tubes, whatever they are because I just don't plain understand 'em.
A fluorescent light source of some kind -- a "cold light" source -- will
give you the most light for the least power (and heat) unless you really
want to use a *lot* of white LEDs. I'm not sure you can get enough output
from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
times with a 10x10 negative, and I am also skeptical that it will be as
even as you'd get with an array of fluorescent tubes.
--
Thor Lancelot Simon tls@rek.tjls,com
"The inconsistency is startling, though admittedly, if consistency is to
be abandoned or transcended, there is no problem." - Noam Chomsky
Re: DIY light source for 10X10" enlarger.
"Thor Lancelot Simon" <tls@panix,com > wrote in message
news:ftiqql$q6d$1@reader2.panix,com ...
> A fluorescent light source of some kind -- a "cold light" source -- will
> give you the most light for the least power (and heat) unless you really
> want to use a *lot* of white LEDs. I'm not sure you can get enough output
> from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
> times with a 10x10 negative, and I am also skeptical that it will be as
> even as you'd get with an array of fluorescent tubes.
This is great, Thor. I appreciate your input.
Are these flourescent sources in round tubes? Or would it be a line of short
tubes? And I gather that they would be left on all the time and I'd use the
lens shutter, correct?
"Thor Lancelot Simon" <tls@panix,com > wrote in message
news:ftiqql$q6d$1@reader2.panix,com ...
> A fluorescent light source of some kind -- a "cold light" source -- will
> give you the most light for the least power (and heat) unless you really
> want to use a *lot* of white LEDs. I'm not sure you can get enough output
> from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
> times with a 10x10 negative, and I am also skeptical that it will be as
> even as you'd get with an array of fluorescent tubes.
This is great, Thor. I appreciate your input.
Are these flourescent sources in round tubes? Or would it be a line of short
tubes? And I gather that they would be left on all the time and I'd use the
lens shutter, correct?
Re: DIY light source for 10X10" enlarger.
On Wed, 09 Apr 2008 12:11:47 -0500, jjs wrote:
> "Thor Lancelot Simon" <tls@panix,com > wrote in message
> news:ftiqql$q6d$1@reader2.panix,com ...
>
>> A fluorescent light source of some kind -- a "cold light" source --
>> will give you the most light for the least power (and heat) unless you
>> really want to use a *lot* of white LEDs. I'm not sure you can get
>> enough output from a 10x10 grid of LEDs you assemble yourself to give
>> decent enlarging times with a 10x10 negative, and I am also skeptical
>> that it will be as even as you'd get with an array of fluorescent
>> tubes.
>
> This is great, Thor. I appreciate your input.
>
> Are these flourescent sources in round tubes? Or would it be a line of
> short tubes? And I gather that they would be left on all the time and
> I'd use the lens shutter, correct?
JJS,
IIRC, one of the Ansel Adams Photo Series books from years ago had
detailed instructions on how Adams built a diffusion head light source
for a horizontal enlarger made from a salvaged 8x10 camera. It used an
array of small incandescent bulbs, opal glass for diffusion, and a vacuum
cleaner for heat removal. Very simple.
I adapted the design to a vertical 4x5 enlarger, using below-the-lens VC
filters. Worked quite well, but when I could afford it, I replaced it
with an Aristo head color balanced for VC paper.
Stef
On Wed, 09 Apr 2008 12:11:47 -0500, jjs wrote:
> "Thor Lancelot Simon" <tls@panix,com > wrote in message
> news:ftiqql$q6d$1@reader2.panix,com ...
>
>> A fluorescent light source of some kind -- a "cold light" source --
>> will give you the most light for the least power (and heat) unless you
>> really want to use a *lot* of white LEDs. I'm not sure you can get
>> enough output from a 10x10 grid of LEDs you assemble yourself to give
>> decent enlarging times with a 10x10 negative, and I am also skeptical
>> that it will be as even as you'd get with an array of fluorescent
>> tubes.
>
> This is great, Thor. I appreciate your input.
>
> Are these flourescent sources in round tubes? Or would it be a line of
> short tubes? And I gather that they would be left on all the time and
> I'd use the lens shutter, correct?
JJS,
IIRC, one of the Ansel Adams Photo Series books from years ago had
detailed instructions on how Adams built a diffusion head light source
for a horizontal enlarger made from a salvaged 8x10 camera. It used an
array of small incandescent bulbs, opal glass for diffusion, and a vacuum
cleaner for heat removal. Very simple.
I adapted the design to a vertical 4x5 enlarger, using below-the-lens VC
filters. Worked quite well, but when I could afford it, I replaced it
with an Aristo head color balanced for VC paper.
Stef
Re: DIY light source for 10X10" enlarger.
Thor Lancelot Simon wrote:
> A fluorescent light source of some kind -- a "cold light" source -- will
> give you the most light for the least power (and heat) unless you really
> want to use a *lot* of white LEDs. I'm not sure you can get enough output
> from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
> times with a 10x10 negative, and I am also skeptical that it will be as
> even as you'd get with an array of fluorescent tubes.
Incandescent bulbs are about 2% effiecient, LEDs 30-40% and flourescent
bulbs about 60%. However more accurately a 15 watt flourescent bulb will
replace a 100 watt bulb.
There is a trade off. An incandescent bulb is a continuous spectrum light
source, all the wavelengths of visible light (and some near IR and UV) are
present. A flourescent bulb, even the ones sold as continuous spectrum plant
lights puts out light in specific color bands. LEDs are even worse as far
as spectrum output and white LEDs are very blue.
This makes color printing near impossible without an incandescent bulb
and will affect variable contrast paper and may affect regular paper.
Incandescent lights have a very short on/off time. Flourescent ones
take longer to start and fade more slowly. Therefore they are not
good for short exposures. What a short exposure is, I can't say.
LEDs are praticaly "instant on", but if you wanted 500 watts of incandescent
light, you would need about 250 watts of LED. If you were to use Phillips
high power LEDs, which run about 3 watts, you would need around 80 of them
and some way to sink the 250 watts of heat. I don't know what they cost,
but I expect that it would be an awfully expensive proposition.
Small LEDs like the ones in flashlights are far smaller so you would need
hundreds of them.
I would build a box with regular lamp sockets and some sort of ventilation.
Passive ventilation would be better for less vibration.
I would place some sort of diffuser at the bottom, possibly several
layers of "opal" glass.
You could start with incandescent bulbs. If you run into heat problems,
you could switch to CFLs (screw in compact flourescent lamps) but you
may need some sort of shutter and delay unit. Properly sequenced, fan on
normally, turn off fan, turn on lights, wait 5 seconds, and then open
the shutter. When the exposure time expired, close shutter, turn off
lamps and turn on fan.
As for incandescent bulbs, you may have to find ones with the
lettering on the side instead of the bottom.
Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson,com N3OWJ/4X1GM
Thor Lancelot Simon wrote:
> A fluorescent light source of some kind -- a "cold light" source -- will
> give you the most light for the least power (and heat) unless you really
> want to use a *lot* of white LEDs. I'm not sure you can get enough output
> from a 10x10 grid of LEDs you assemble yourself to give decent enlarging
> times with a 10x10 negative, and I am also skeptical that it will be as
> even as you'd get with an array of fluorescent tubes.
Incandescent bulbs are about 2% effiecient, LEDs 30-40% and flourescent
bulbs about 60%. However more accurately a 15 watt flourescent bulb will
replace a 100 watt bulb.
There is a trade off. An incandescent bulb is a continuous spectrum light
source, all the wavelengths of visible light (and some near IR and UV) are
present. A flourescent bulb, even the ones sold as continuous spectrum plant
lights puts out light in specific color bands. LEDs are even worse as far
as spectrum output and white LEDs are very blue.
This makes color printing near impossible without an incandescent bulb
and will affect variable contrast paper and may affect regular paper.
Incandescent lights have a very short on/off time. Flourescent ones
take longer to start and fade more slowly. Therefore they are not
good for short exposures. What a short exposure is, I can't say.
LEDs are praticaly "instant on", but if you wanted 500 watts of incandescent
light, you would need about 250 watts of LED. If you were to use Phillips
high power LEDs, which run about 3 watts, you would need around 80 of them
and some way to sink the 250 watts of heat. I don't know what they cost,
but I expect that it would be an awfully expensive proposition.
Small LEDs like the ones in flashlights are far smaller so you would need
hundreds of them.
I would build a box with regular lamp sockets and some sort of ventilation.
Passive ventilation would be better for less vibration.
I would place some sort of diffuser at the bottom, possibly several
layers of "opal" glass.
You could start with incandescent bulbs. If you run into heat problems,
you could switch to CFLs (screw in compact flourescent lamps) but you
may need some sort of shutter and delay unit. Properly sequenced, fan on
normally, turn off fan, turn on lights, wait 5 seconds, and then open
the shutter. When the exposure time expired, close shutter, turn off
lamps and turn on fan.
As for incandescent bulbs, you may have to find ones with the
lettering on the side instead of the bottom.
Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel gsm@mendelson,com N3OWJ/4X1GM
Re: DIY light source for 10X10" enlarger.
On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
> As for incandescent bulbs, you may have to find ones with the
> lettering on the side instead of the bottom.
There are ways to remove the lettering on the bottom. (Don't ask me how
I know that.)
--
The best argument against democracy is a five-minute
conversation with the average voter.
- Attributed to Winston Churchill
On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
> As for incandescent bulbs, you may have to find ones with the
> lettering on the side instead of the bottom.
There are ways to remove the lettering on the bottom. (Don't ask me how
I know that.)
--
The best argument against democracy is a five-minute
conversation with the average voter.
- Attributed to Winston Churchill
Re: DIY light source for 10X10" enlarger.
On Wed, 09 Apr 2008 10:43:19 -0700, David Nebenzahl wrote:
> On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
>
>> As for incandescent bulbs, you may have to find ones with the lettering
>> on the side instead of the bottom.
>
> There are ways to remove the lettering on the bottom. (Don't ask me how
> I know that.)
Use acetone. Fingernail polish remover will do--It's mostly acetone--but
you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
oil) after to remove the additives in the polish remover left on the bulb
that keep the nails from becoming dry and brittle.
Stef
On Wed, 09 Apr 2008 10:43:19 -0700, David Nebenzahl wrote:
> On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
>
>> As for incandescent bulbs, you may have to find ones with the lettering
>> on the side instead of the bottom.
>
> There are ways to remove the lettering on the bottom. (Don't ask me how
> I know that.)
Use acetone. Fingernail polish remover will do--It's mostly acetone--but
you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
oil) after to remove the additives in the polish remover left on the bulb
that keep the nails from becoming dry and brittle.
Stef
Re: DIY light source for 10X10" enlarger.
In article <3HsLj.29112$6J3.22630@newsfe13.phx>,
Stefan Patric <tootek2@yahoo,com > wrote:
> On Wed, 09 Apr 2008 10:43:19 -0700, David Nebenzahl wrote:
>
> > On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
> >
> >> As for incandescent bulbs, you may have to find ones with the lettering
> >> on the side instead of the bottom.
> >
> > There are ways to remove the lettering on the bottom. (Don't ask me how
> > I know that.)
>
> Use acetone. Fingernail polish remover will do--It's mostly acetone--but
> you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
> oil) after to remove the additives in the polish remover left on the bulb
> that keep the nails from becoming dry and brittle.
>
> Stef
And David breath very deeply while using it.
--
Reality is a picture perfected and never looking back.
In article <3HsLj.29112$6J3.22630@newsfe13.phx>,
Stefan Patric <tootek2@yahoo,com > wrote:
> On Wed, 09 Apr 2008 10:43:19 -0700, David Nebenzahl wrote:
>
> > On 4/9/2008 10:19 AM Geoffrey S. Mendelson spake thus:
> >
> >> As for incandescent bulbs, you may have to find ones with the lettering
> >> on the side instead of the bottom.
> >
> > There are ways to remove the lettering on the bottom. (Don't ask me how
> > I know that.)
>
> Use acetone. Fingernail polish remover will do--It's mostly acetone--but
> you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
> oil) after to remove the additives in the polish remover left on the bulb
> that keep the nails from becoming dry and brittle.
>
> Stef
And David breath very deeply while using it.
--
Reality is a picture perfected and never looking back.
Re: DIY light source for 10X10" enlarger.
> you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
> oil)
It better not contain oil. I use it all the time to wipe plastic before
priming it for paint. Ain't no oil in it.
> you'll need to use isopropyl alcohol (NOT rubbing alcohol--it contains
> oil)
It better not contain oil. I use it all the time to wipe plastic before
priming it for paint. Ain't no oil in it.
Re: DIY light source for 10X10" enlarger.
"jjs" <jjs.jjs,net > wrote
> > ... rubbing alcohol--it contains oil ...
> It better not contain oil. I use it all the time to wipe plastic before
> priming it for paint. Ain't no oil in it.
It depends -- there are two types of 70% 'rubbing alcohol': isopropanol and
denatured ethanol. The denatured ethanol is for medical use and labeled
USP.
Then there are 9x% isopropanol and various witch hazel libations.
I have, on occasion, picked up the wrong stuff. The USP version has a
distinct Doctor's office odeur and sometimes a light pink tint.
--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http :// www .darkroomautomation,com /index2.htm
n o lindan at ix dot netcom dot com
"jjs" <jjs.jjs,net > wrote
> > ... rubbing alcohol--it contains oil ...
> It better not contain oil. I use it all the time to wipe plastic before
> priming it for paint. Ain't no oil in it.
It depends -- there are two types of 70% 'rubbing alcohol': isopropanol and
denatured ethanol. The denatured ethanol is for medical use and labeled
USP.
Then there are 9x% isopropanol and various witch hazel libations.
I have, on occasion, picked up the wrong stuff. The USP version has a
distinct Doctor's office odeur and sometimes a light pink tint.
--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http :// www .darkroomautomation,com /index2.htm
n o lindan at ix dot netcom dot com
Re: DIY light source for 10X10" enlarger.
Nicholas:
Are you sure on the medical ethanol?
USP means United States Pharmacopeia, taken to mean "of highest purity"
(after "reagent" and "analytic" grades of chemicals). The only ethanol
USP I have ever come across is 100% ethanol, prepared from a benzene
ternary azeotrope made after alcohol distillation to a binary azeotrope
(95% ethanol in water), then with the last trace of water removed with
magnesium. It's not denatured, and at least used to carry a federal tax
stamp as potable alcohol (although very expensive for the concentration
of alcohol, much cheaper to buy vodka and drink twice the volume).
Denatured alcohol isn't generally used for medical purposes because the
most common denaturants (most common is methanol) are toxic, and many
are skin-absorbed.
David
David Kazdan, MD, PhD
Cleveland, Ohio
Nicholas O. Lindan wrote:
> "jjs" <jjs.jjs,net > wrote
>>> ... rubbing alcohol--it contains oil ...
>> It better not contain oil. I use it all the time to wipe plastic before
>> priming it for paint. Ain't no oil in it.
>
> It depends -- there are two types of 70% 'rubbing alcohol': isopropanol and
> denatured ethanol. The denatured ethanol is for medical use and labeled
> USP.
>
> Then there are 9x% isopropanol and various witch hazel libations.
>
> I have, on occasion, picked up the wrong stuff. The USP version has a
> distinct Doctor's office odeur and sometimes a light pink tint.
>
Nicholas:
Are you sure on the medical ethanol?
USP means United States Pharmacopeia, taken to mean "of highest purity"
(after "reagent" and "analytic" grades of chemicals). The only ethanol
USP I have ever come across is 100% ethanol, prepared from a benzene
ternary azeotrope made after alcohol distillation to a binary azeotrope
(95% ethanol in water), then with the last trace of water removed with
magnesium. It's not denatured, and at least used to carry a federal tax
stamp as potable alcohol (although very expensive for the concentration
of alcohol, much cheaper to buy vodka and drink twice the volume).
Denatured alcohol isn't generally used for medical purposes because the
most common denaturants (most common is methanol) are toxic, and many
are skin-absorbed.
David
David Kazdan, MD, PhD
Cleveland, Ohio
Nicholas O. Lindan wrote:
> "jjs" <jjs.jjs,net > wrote
>>> ... rubbing alcohol--it contains oil ...
>> It better not contain oil. I use it all the time to wipe plastic before
>> priming it for paint. Ain't no oil in it.
>
> It depends -- there are two types of 70% 'rubbing alcohol': isopropanol and
> denatured ethanol. The denatured ethanol is for medical use and labeled
> USP.
>
> Then there are 9x% isopropanol and various witch hazel libations.
>
> I have, on occasion, picked up the wrong stuff. The USP version has a
> distinct Doctor's office odeur and sometimes a light pink tint.
>
Re: DIY light source for 10X10" enlarger.
In article <%R9Mj.3379$vF.3207@newssvr21.news.prodigy,net >,
David Kazdan <dxk10@cwru.edu> wrote:
>
> Denatured alcohol isn't generally used for medical purposes because the
> most common denaturants (most common is methanol) are toxic, and many
> are skin-absorbed.
>
> David
>
> David Kazdan, MD, PhD
> Cleveland, Ohio
http :// www .jtbaker,com /msds/englishhtml/E2012.htm
"ETHYL ALCOHOL COMPLETELY DENATURED
1. Product Identification
Synonyms: Alcohol; spirits of wine; potato alcohol; CDA Formula 19
CAS No.: Not applicable to mixtures.
Molecular Weight: Not applicable to mixtures.
Chemical Formula: Not applicable to mixtures.
Product Codes: 3791, 7018
2. Composition/Information on Ingredients
Ingredient CAS No Percent
Hazardous
--------------------------------------- ------------ ------------
---------
Ethyl Alcohol 64-17-5 95%
Yes
Methyl Isobutyl Ketone 108-10-1 4%
Yes
Kerosene 8008-20-6 < 1%
Yes "
--
Reality is a picture perfected and never looking back.
In article <%R9Mj.3379$vF.3207@newssvr21.news.prodigy,net >,
David Kazdan <dxk10@cwru.edu> wrote:
>
> Denatured alcohol isn't generally used for medical purposes because the
> most common denaturants (most common is methanol) are toxic, and many
> are skin-absorbed.
>
> David
>
> David Kazdan, MD, PhD
> Cleveland, Ohio
http :// www .jtbaker,com /msds/englishhtml/E2012.htm
"ETHYL ALCOHOL COMPLETELY DENATURED
1. Product Identification
Synonyms: Alcohol; spirits of wine; potato alcohol; CDA Formula 19
CAS No.: Not applicable to mixtures.
Molecular Weight: Not applicable to mixtures.
Chemical Formula: Not applicable to mixtures.
Product Codes: 3791, 7018
2. Composition/Information on Ingredients
Ingredient CAS No Percent
Hazardous
--------------------------------------- ------------ ------------
---------
Ethyl Alcohol 64-17-5 95%
Yes
Methyl Isobutyl Ketone 108-10-1 4%
Yes
Kerosene 8008-20-6 < 1%
Yes "
--
Reality is a picture perfected and never looking back.
Re: DIY light source for 10X10" enlarger.
"David Kazdan" <dxk10@cwru.edu> wrote
> Are you sure on the medical ethanol?
The key words seem to be 'rubbing' and 'USP'...
o "Rubbing alcohol" w/o USP is 70% isopropanol
o "70% isopropanol USP" is not, TTBOMK, labeled 'rubbing'
o "Rubbing alcohol USP" is 70% ethanol w/ acetone and bittering
o "Alcohol USP" is ethanol
I think the logic is that acetone is less poisonous than
isopropanol and paying ATF tax on ethanol for use as rubbing
alcohol is bad for the bottom line not to mention it's
effect on the level of sin in both the massage parlour
business and the hospital's PM&R department.
Advice worth price charged and if challenged I
will disavow all knowledge ...
--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http :// www .darkroomautomation,com /index2.htm
n o lindan at ix dot netcom dot com
"David Kazdan" <dxk10@cwru.edu> wrote
> Are you sure on the medical ethanol?
The key words seem to be 'rubbing' and 'USP'...
o "Rubbing alcohol" w/o USP is 70% isopropanol
o "70% isopropanol USP" is not, TTBOMK, labeled 'rubbing'
o "Rubbing alcohol USP" is 70% ethanol w/ acetone and bittering
o "Alcohol USP" is ethanol
I think the logic is that acetone is less poisonous than
isopropanol and paying ATF tax on ethanol for use as rubbing
alcohol is bad for the bottom line not to mention it's
effect on the level of sin in both the massage parlour
business and the hospital's PM&R department.
Advice worth price charged and if challenged I
will disavow all knowledge ...
--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http :// www .darkroomautomation,com /index2.htm
n o lindan at ix dot netcom dot com
Re: DIY light source for 10X10" enlarger.
FWIW - 70% isopropyl is preferred over 100% alcohol for disinfectanting it
penetrates the membrane of tubercle bacillus to disable it while 100% does
not. At least forty years ago it was so believed. That's the last time I
checked. :)
OB darkroom - What part did alcohol have in the film developer Ethanol Blue?
FWIW - 70% isopropyl is preferred over 100% alcohol for disinfectanting it
penetrates the membrane of tubercle bacillus to disable it while 100% does
not. At least forty years ago it was so believed. That's the last time I
checked. :)
OB darkroom - What part did alcohol have in the film developer Ethanol Blue?
Re: DIY light source for 10X10" enlarger.
Serves me right for not checking a bottle in the medicine cabinet--I
thought that chemicals labeled USP were "pure." At any rate, ethyl
alcohol USP is not denatured, is it?
David
Nicholas O. Lindan wrote:
> "David Kazdan" <dxk10@cwru.edu> wrote
>> Are you sure on the medical ethanol?
>
> The key words seem to be 'rubbing' and 'USP'...
>
> o "Rubbing alcohol" w/o USP is 70% isopropanol
>
> o "70% isopropanol USP" is not, TTBOMK, labeled 'rubbing'
>
> o "Rubbing alcohol USP" is 70% ethanol w/ acetone and bittering
>
> o "Alcohol USP" is ethanol
>
> I think the logic is that acetone is less poisonous than
> isopropanol and paying ATF tax on ethanol for use as rubbing
> alcohol is bad for the bottom line not to mention it's
> effect on the level of sin in both the massage parlour
> business and the hospital's PM&R department.
>
> Advice worth price charged and if challenged I
> will disavow all knowledge ...
>
Serves me right for not checking a bottle in the medicine cabinet--I
thought that chemicals labeled USP were "pure." At any rate, ethyl
alcohol USP is not denatured, is it?
David
Nicholas O. Lindan wrote:
> "David Kazdan" <dxk10@cwru.edu> wrote
>> Are you sure on the medical ethanol?
>
> The key words seem to be 'rubbing' and 'USP'...
>
> o "Rubbing alcohol" w/o USP is 70% isopropanol
>
> o "70% isopropanol USP" is not, TTBOMK, labeled 'rubbing'
>
> o "Rubbing alcohol USP" is 70% ethanol w/ acetone and bittering
>
> o "Alcohol USP" is ethanol
>
> I think the logic is that acetone is less poisonous than
> isopropanol and paying ATF tax on ethanol for use as rubbing
> alcohol is bad for the bottom line not to mention it's
> effect on the level of sin in both the massage parlour
> business and the hospital's PM&R department.
>
> Advice worth price charged and if challenged I
> will disavow all knowledge ...
>
