Light in darkroom ??
 

Hi guys,
I am going to start developing my own c41 color film.
for loading the color film into the container.., can you use any color of lightbulb, or do you have to do it in a bag, totally dark.

thanks,
Kevin Rea
Lancaster, Calif.

Light in darkroom ??
 

"kevinrea" wrote

Hi guys,
I am going to start developing my own c41 color film.
for loading the color film into the container.., can you use any color
of lightbulb, or do you have to do it in a bag, totally dark.

Totally dark. I think the only film with which you can use a light bulb (a
red one, specifically) is orthochromatic, which is not red sensitive.

Light in darkroom ??
 

Howard Lester wrote:
Totally dark. I think the only film with which you can use a light bulb (a
red one, specifically) is orthochromatic, which is not red sensitive.

Kodak used to sell a dark green filter which could be used only for a
few seconds after development was half complete. I think it was designed
for panchromatic film, not color.

A friend of mine had one in his darkroom, which was really the unfinished
area under a staircase, which had a toilet and sink, so it was sold as
a "1/2 bath". The light leaking in from the other room was brighter than
the safelight.

After that I never used one myself, and just did it by feel.

I know the OP asked about color film, I'm not sure it would matter.
The timing and temperature is critical not only for density but color
balance.

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379
"Owning a smartphone: Technology's equivalent to learning to play
chopsticks on the piano as a child and thinking you're a musician."
(sent to me by a friend)

Light in darkroom ??
 

On 2012-10-10 02:05:05 +0000, kevinrea said:

Hi guys,
I am going to start developing my own c41 color film.
for loading the color film into the container.., can you use any color
of lightbulb, or do you have to do it in a bag, totally dark.

thanks,
Kevin Rea
Lancaster, Calif.

Color film must be loaded into the tank in complete darkness. After the
tank is loaded and closed, everything else is done in room light.
--
Michael

Light in darkroom ??
 

Geoffrey S. Mendelson wrote:
Howard Lester wrote:
Totally dark. I think the only film with which you can use a light bulb (a
red one, specifically) is orthochromatic, which is not red sensitive.

Kodak used to sell a dark green filter which could be used only for a
few seconds after development was half complete. I think it was designed
for panchromatic film, not color.

I toured the Kodak Kodachrome development lab in Fair Lawn, New Jersey
back when it was a serious operation. Probably in the late 1960s.

Note that Kodachrome came in speeds of 25 and 64. Later there was a 200
speed version in 120 if I remember correctly, but I never saw that. I
know that they had a dip and dumk machine for larger size film. I am
sure they no longer made it in sheets. Maybe that was for E-6.

Anyhow, some of the line operated in dim room light, but the beginning
was in a totally black dark room. There was one of those dark green
safelights in the top corner of the room, as far from the film loading
station as possible. It did not put out enough light to see anything. It
was just bright enough so when you dark-adapted you could see where it was.

They normally left it off, but when they hired a trainee, they would
turn it on just so the trainee could orient him or her self.

Once they loaded about 1000 feet of the stuff on a light-tight roll,
they closed the thing and passed it out through a light trap (double
door setup where only one door could be opened at a time). That was
stuck in the begin end of the line where it was washed, etc. Eventually
it got to where the re-exposures were done and the color couplers were
put in for three separate color development stages. You could see that,
though the room was not brightly lit. I think by that point, all silver
development was done and the remaining silver halide fixed out. They had
an analytical chemist and a sensitometrist on duty all the time. They
spliced a test strip after every so many customer rolls, and measured it
and balanced the chemistry replenishment rates based on the results of
those tests. They plotted the results over an extended interval so they
could see trends before they became a problem.

What amazed me was a separate line where the 1000 foot reels of
processed and dried film were mounted in those little cardboard mounts.
This was done by a team of women operating machines. Since each camera
has a different pitch between the frames, and some cameras have
irregular film advance mechanisms, this is done essentially by hand, but
these women were so good at it that they could do a roll amazingly fast.
The machine fed the new mounts, the yellow boxes where the slides went,
the mailing labels, and so on. It also advanced the film, but the
operator had a knob to align the edge of the frame with the edge of the
mount. When they got some images where they could not tell where the
edge of the frame was (too dark), they guessed (as far as I could tell).
That part of the room was well lit, and perhaps a little brighter than
normal. I bet they did not have to work an 8-hour shift though, because
they would probably become less alert than required. Perhaps then they
loaded film for processing or something.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key:3EDBB65E 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 09:25:01 up 9 days, 16:26, 3 users, load average: 4.81, 4.77, 4.79