Red light and negative &w film.

[galileo42]

<p>I never thought of asking because I never needed to, but I'm getting curious: we all know that the red light in a darkroom allows you to work printing paper without exposing it to harmful light. But what about negative b&w film? Is it sensible to that same red light or not? Sorry for asking what will seem obvious to many.</p>

[vincent_peri]

<p>I shoot Kodak Tri-X and sometimes Ilford HP5. They are sensitive to red light.</p>

[tom_s.]

<p>Most black and white films are "Panchromatic" - sensitive to all colors of light. A safelight cannot be used. This is the source of film names such as "Tri-X Pan", "Plus-X Pan", Pan = Panchromatic.<br>

Some older blank and white films are "Orthochromatic" - not sensitive to red light, and therefore could be developed under a red safelight. There might still be one or two ortho films available if you want to try it.<br>

Most printing paper can be developed under amber light ("OC" filter) as well as red light, as it ignores an even broader range of colors.</p>

[leicaglow]

<p>No, you can't use a red light. They make a dark green light, but a) it's so dark it doesn't seem to help me much, and b) it can still fog film.</p>

[frank.schifano]

<p>Ilford used to have Ortho Plus, which was available only in sheet sizes. I see no mention of it on their web site when I checked. They may have dropped it from their catalog. I've used it and it can be developed under a dark red safelight like a Kodak #1. Adox makes Ortho 25 in 35 mm and sheet film sizes. Its spectral response is 380 to 610 nm, and should be safe under the same type of safelight. Just about everything else is sensitive to the whole visible spectrum, and even some of the invisible spectrum. If you read the tech sheets for the film you're using, more often than not is says, usually in bold lettering, something like "open in total darkness" or "handle in total darkness."</p>

<p>Take a look at Kodak's publication #TI0845 and compare the safelight filter's output to the spectral response of the film you want to use. If the film is insensitive to the spectral output of the safelight, then it's safe. If the filter puts out light to which the film is sensitive, it's not. There's your answer. Probably more than you wanted to know. But hey, those are the facts. <br /> </p>

[galileo42]

<p>That's what I thought. Panchromatic, of course. I guess I'll keep loading my reels in the dark. Thank you all.</p>

[Fotohuis RoVo]

<p>You can not use red light (620nm) for most B&W films due to the fact most films are panchromatic that means sensitive from 250nm (UV) till 650nm - 680nm (dark red/NIR). Only Ortho films you can use with red light. They are sensitized till 600nm.<br>

Example: Rollei Ortho 25, available in 35mm, 120 roll film and sheet film. All ortho films are slow speed films but with a remarkable high resolving power: >330lp/mm. The log D curve is rather steep therefore use a low contrast document developer for these films (e.g. Rollei Low Contrast) or a 1+150 Rodinal dilution.</p>

[profhlynnjones]

<p>Panchromatic films NEVER</p>

<p>Orthochromatic or commercial (color blind) films, YES</p>

<p>Lynn</p>

[frank.schifano]

<p>A word about the dark green filters. Recommended usage is only AFTER the film is at least 1/2 way through the development step; then only for a few seconds. And, like Michael wrote, they're too dim to be of any use other than to orient yourself in the darkroom. As a device to allow development by inspection, they're useless. I have one. Ran a few tests with it and put it away for good. If you crank up the output with a stronger lamp, it will fog the film. There's no getting around it.</p>

[terence_spross1]

<p>Now that video camdorders are available with IR light sources and are sensitive to IR its another option to inspecting films in the darkroom.<br>

mod for camcorder: (to be used as a closed circuit camera -not actually recording)<br>

1. Cover or disconnect any visible red LED indicating camera is in operation., Close or disable any self illuminated LCD display.<br>

2. Cover the IR LED with a IR filter to filter out any visible light. (Impurities in the LED allow some red visible light to occur.)<br>

3. Connect a small TV monitor adjusted to very dim and cover it with baffles and a shroud. The shroud you pull over your head is the same one used for large format photographers use to keep the sunlight out of the ground glass of their view cameras. Here it keeps the light in. Position it where you can see but your hands are still working with the film tank.<br>

4. Using small tabletop tripod set camera is positon to focus on open film at a convient position next to the tank.<br>

During development pull a full frames off the reel to examine the result quickly. Develop know film in a repeatable way and observe how it looks at various stages of development. Now you know what it should look like at the end of normal development. Then process your unknown roll with the same uncompensating developer so pushing is possible if necessary and observe it at regular intervals during development.<br>

When processing unknown rolls this proves invaluable.<br>

(As long as you are certain that the unknown roll isn't infared film ;-)</p>

[ken_miranda]

<p>In my intro to Photography class, I was rolling Kodak Tri-X 400 film in one of dark rooms and I noticed I didn't fully shut the door. When I finish rolling I noticed there was a crack of light coming from the bottom of the door and later found out that half my film was light expose.</p>

[paul ron]

a fellow here on apug once said he uses a toy

night vision scope he got at wallmart for $30.

[glen_h]

<p>Not so many years before I started in photography, orthochromatic films were common. I suspect that for some years the advantage of developing under red light discouraged the development of panchromatic films.</p>

<p>Silver bromide is naturally sensitive to blue and shorter wavelength (higher photon energy). Sensitizing dyes are added to the film to make it sensitive down through green (ortho) or through red (panchromatic). These dyes adsorb (stick to the surface) of silver bromide grains. During development, they mostly wash off (sometimes turning the developer pink) and so reduce the sensitivity to those colors. As green is the maximum sensitivity of the human eye, a dark green safelight allows a short look after the dyes are mostly gone. I have never found it worth trying, but then again I mostly use Diafine where there isn't much use in doing it.</p>

<p>I suppose some might try ortho film just for the experience.</p>

<p> </p>

[glen_h]

<p><img src="https://img1.etsystatic.com/068/1/10528271/il_214x170.756553663_o80k.jpg" alt="Brownie Darkroom Lamp Kit by Kodak - Still works!" /><br>

When I first started in photography, we bought a red safelight like the one shown from goodwill, along with some other photography supplies. At that time, about 1967, Kodak had changed to the yellow and green shown. The red was from the orthochromatic days.</p>

[Mike Gammill]

<p>The only time I've ever used a red light for film was I once had an old roll of Verichrome (not Verichrome Pan) that was size 116, I think, so I had to process it in a tray since I did not have a reel that fit. The red light was helpful.</p>

[glen_h]

<p>I had a roll of Verichrome 116 a few years ago, but I have a tank for it. It was too fogged to see anything. (About 70 years old.)</p>

<p>I did tray develop VP122 in the dark. I practiced with some 35mm film to be sure I could find the trays. My grandfather told be about tray developing not long before I had my first roll to develop, but I already had a tank by then. Almost 50 years later, I finally get to try it.</p>

<p>It came out fine, but it did like to curl up near the beginning. That was with Diafine, so four trays. I put enough space between the developer trays and the water/stop trays to prevent accidents and splashing. I have another roll of VP122 to do sometime, but I will use HC110 for that one.</p>

 

[r_david]

<p>I tried to use a green light to make sure my reels were loaded properly - nothing that jumped its track and touched another part of the negative.</p>

<p>I stopped because it was useless and you had to have the reel on top of the light to actually see anything - even when eyes were adjusted - and I ended up with slightly fogged film if it was ISO400.</p>