red darkroomlight warning

tedr1

Member
Joined
Feb 3, 2016
Messages
940
Location
50 miles from NYC USA
Format
Multi Format
Sorry to hear about the fogged film.
As I'm sure you are aware like most modern films that is panchromatic type film having red sensitivity. For the first hundred years or so plates and films were red-insensitive, "orthochromatic" type, and a red safelight was the norm!
 

Louis Nargi

Member
Joined
Sep 4, 2004
Messages
398
Format
4x5 Format
I thought you could use a dim green light when developing by inspection.
 

Paul Howell

Subscriber
Joined
Dec 23, 2004
Messages
9,614
Location
Scottsdale Az
Format
Multi Format
Very dim, with green light for very short inspection times. I have a few packets of Ansco pinakryptol green desensitizer, with a 10 watt green safe light, at 3 feet, no more than 10 seconds every minute with development time extended by 50%. You can use a red safe light with Orth film.
 

mshchem

Subscriber
Joined
Nov 26, 2007
Messages
14,518
Location
Iowa City, Iowa USA
Format
Medium Format
I remember as a kid, probably around 1970, I was in my local camera store. The phone rang, a customer who had just purchased a 100 foot roll of Tri-X called. He asked somewhat sheepishly "How much light could the bulk roll take?" The sales person replied "As much as it can get!" .

My mistakes have included keeping color paper in the same paper safe as black and white. That's not good when you forget using an amber filter.
 

jim10219

Member
Joined
Jun 15, 2017
Messages
1,632
Location
Oklahoma
Format
4x5 Format
I know some people use infrared goggles to develop film by inspection. Though I'd imagine that it would still fog IR films.

I went over to a photographers home once and he developed film under a red light. I thought he was crazy, but it turned out it was okay because it was x-ray film. Though even then, he was careful to limit it's exposure.
 

ic-racer

Member
Joined
Feb 25, 2007
Messages
16,529
Location
USA
Format
Multi Format
View the green disk of the safelight through the film and learn to judge the densest areas for appropriate development. The amount of light fogging the film from the safelight diminishes as it is moved farther from the film, but the intensity of the green disk is the same to your eye (or spot meter) as the lamp is moved away (the green disk just gets smaller). Development by inspection uses this trick to your advantage.

 
OP
OP

RalphLambrecht

Subscriber
Joined
Sep 19, 2003
Messages
14,631
Location
K,Germany
Format
Medium Format
RalphLambrecht said:
Yes ,Ilford states"process in total darkness" but I thought: Our darkroom redlight is so dark that can't possibly hurt anything. Well, bad news, it ruined three rolls of 120 Ilford FP4+. the film is totally fogged;process only in total darkness!
Click to expand...
a test ysterdat with TriX revealed that it took only 2 min to fog the film.
 

Nokton48

Member
Joined
Oct 8, 2006
Messages
2,975
Format
Multi Format
I used to use a fair amount of Ilford Commercial sheet film, which is Orthochromatic.
And Tri-X Ortho also orthochromatic.
J Lane Glass Plates are also Orthochromatic.

Can be loaded and processed in my red safelighted darkroom.

Panchromatic film quickly fogs under red light.
 
Last edited:

pentaxuser

Member
Joined
May 9, 2005
Messages
19,809
Location
Daventry, No
Format
35mm
RalphLambrecht said:
a test ysterdat with TriX revealed that it took only 2 min to fog the film.
Click to expand...
Ralph, while knowing nothing about the sensitivity of panchromatic film with a red safelight I must admit to being surprised by as long as two minutes. It makes me wonder if you tried development by inspection after say 50-70% % of the development period and could assess a negative very well in say 10-15 secs, might you get away without fogging?

The good news would seem to be that if you accidentally turned the red light on but then turned it off again after say 5-10 secs your film would be OK?

pentaxuser
 

markbau

Member
Joined
Apr 16, 2009
Messages
867
Location
Australia
Format
Analog
Why would anyone think that PANchromatic film can tolerate ANY light in the darkroom? It's sensitive to the whole visible spectrum, isn't it?
 

pentaxuser

Member
Joined
May 9, 2005
Messages
19,809
Location
Daventry, No
Format
35mm
markbau said:
Why would anyone think that PANchromatic film can tolerate ANY light in the darkroom? It's sensitive to the whole visible spectrum, isn't it?
Click to expand...
Well it seems to clearly tolerate a very small amount of red light. I loaded a film the other night and towards the end of the loading I was aware of a very dim red glow in a corner of the darkroom. It was the pinpoint of light from my AC/DC adaptor for my lightbox to indicate that it is plugged in. Yes it was behind my print dryer and is literally a small point of red light but as my eyes had become used to the dark by then I was aware of it and certainly the light level in that corner of the room was visible.

I developed the film and it was fine. Clearly there is a world of difference between this and a red safelight which is higher in wattage, more strategically placed to light the room and has a 8x10 red glass plate in front of the 15 W bulb but my experience indicates that a pinpoint of red light some distance does not automatically fog the film. It was Kentmere 400 by the way

pentaxuser
 
OP
OP

RalphLambrecht

Subscriber
Joined
Sep 19, 2003
Messages
14,631
Location
K,Germany
Format
Medium Format
markbau said:
Why would anyone think that PANchromatic film can tolerate ANY light in the darkroom? It's sensitive to the whole visible spectrum, isn't it?
Click to expand...
Because , I can hardly see anything in that darkroom;to me it is completely dark but the film is still sensitive to it;that did surprise me a bit.When Ilford says process in total darkness,they mean in TOTAL darkness.
 

Nodda Duma

Member
Joined
Jan 22, 2013
Messages
2,685
Location
Batesville, Arkansas
Format
Multi Format
RalphLambrecht said:
a test ysterdat with TriX revealed that it took only 2 min to fog the film.
Click to expand...

If I remember correctly, FP4+ has extended red sensitivity compared to TriX. TBH I’m surprised TriX could tolerate red light for so long. Makes me wonder about the possibility of coating panchromatic plates. What filter were you using?
 

Paul Howell

Subscriber
Joined
Dec 23, 2004
Messages
9,614
Location
Scottsdale Az
Format
Multi Format
In the day's of old development by inspection was used for sheet film. We forget that in the 50 and early 60s most commercial work was done with 4X5 and 8X10 sheet film. I recall in college developing a couple of sheets of 4X5 by inspection for a class assignment. I have no idea how I would develop roll film, winding unwinding, using the see saw method? If someone needs to see in a dark room the only method I know of is using IR goggles.
 

Bob Carnie

Subscriber
Joined
Apr 18, 2004
Messages
7,735
Location
toronto
Format
Med. Format RF
RalphLambrecht said:
Yes ,Ilford states"process in total darkness" but I thought: Our darkroom redlight is so dark that can't possibly hurt anything. Well, bad news, it ruined three rolls of 120 Ilford FP4+. the film is totally fogged;process only in total darkness!
Click to expand...
RalphLambrecht said:
Because , I can hardly see anything in that darkroom;to me it is completely dark but the film is still sensitive to it;that did surprise me a bit.When Ilford says process in total darkness,they mean in TOTAL darkness.
Click to expand...
Ok Ralph I am selling my book of yours after reading this.
 

JPD

Member
Joined
Mar 24, 2007
Messages
2,152
Location
Sweden
Format
Medium Format
I have one of those green filters for my darkroom lamp, with a 15W bulb. It's so dark that I can't see anything with it anyway, so that was a vaste of money. Perhaps my eyes is less sensitive to faint green light than yours, I don't know. Yes, I did wait for a couple of minutes for my eyes to adjust, but to no avail.

So for me it's total darkness when handling panchromatic film, and red light when using orthochromatic films.
 

pentaxuser

Member
Joined
May 9, 2005
Messages
19,809
Location
Daventry, No
Format
35mm

Same here I had a Durst Tricolor safelight that had a dark green option. After about 15 minutes I think I could just about make out my hand waving rapidly in front of my face at about 45 cms but frankly it might have been my imagination and a form of auto-suggestion i.e. I knew I was waving my hand and there must have been some illumination in the room as light was on with the dark green and thus I must have been able to see my hand

It was frankly useless.

pentaxuser
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
52,601
Location
Delta, BC Canada
Format
Medium Format
Bob Carnie said:
Ok Ralph I am selling my book of yours after reading this.
Click to expand...
Keep the parts on printing - safelights are allowed.
By the way, just because you can see a source of light in your darkroom doesn't mean that that light actually reaches the light sensitive material. Light doesn't easily travel around curves.
 

DREW WILEY

Member
Joined
Jul 14, 2011
Messages
13,865
Format
8x10 Format
Unless it's Ortho film, you're gambling. If you look at the published spectrogram of any pan film you'll see the sensitivity is just slightly depressed in green. Red sensitivity varies somewhat with specific film. I've had even faint red LED control buttons several feet away fog shadow values in film, even luminous dial tips on old style Gralab timers. Now anything like that goes on a shelf below the sink where the film itself can't see it.
 

MattKing

Moderator
Moderator
Joined
Apr 24, 2005
Messages
52,601
Location
Delta, BC Canada
Format
Medium Format
All wise and good.
I just like to discourage panic unless and until panic becomes necessary.
In my temporary darkroom, I often have to rely on being able to shade film I am working with (loading on to reels) from faint light sources that are behind me as I stand and work. I have had success with this for years.
On the subject of developing by inspection I wonder whether the differences in individuals' vision - in particular their ability to see colour - may at least partially explajn why some people are able to use the procedure, while others are not.
 

DREW WILEY

Member
Joined
Jul 14, 2011
Messages
13,865
Format
8x10 Format
Sounds like voodoo to me. People work with the same arcane film year after year. Some of them are old school and tend to make overexposed "thick" negatives for contact printing, and might not even notice excess fbf or deep shadow muddiness that would drive me nuts. But there were also once pro sheet film developers in assembly-line like big labs who even took their lunch break via safelight, lest their visual accommodation to the darkness get spoiled.
 

Nodda Duma

Member
Joined
Jan 22, 2013
Messages
2,685
Location
Batesville, Arkansas
Format
Multi Format
@MattKing there is definitely a difference in both photopic and scotopic response in people. The high schooler who coats plates for me cannot see as well in the dark as I can..makes it tough to set up the safelights for her to use since they are a compromise between seeing and fogging.
 

DREW WILEY

Member
Joined
Jul 14, 2011
Messages
13,865
Format
8x10 Format
Normal human vision is more sensitive to green light than to red.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…