Develop photos?
Stupid question, just popped into my head while I was watching a movie.
Tell me, why was/is red light used to develop photos? Why not green or blue, or why in a closed, dark room (dark camera) at all? I also understand that the photos are then chemically soaked in a liquid and then have to be hung up.
So, I know that the photo needs to be exposed to develop. Back then, for example, you had to stand for over 10 minutes (I think) so that the reflected light could project through the lens onto the format/image cartridge.
I was born in the late '70s, and my father took my picture back in the '80s with a Polaroid instant camera. They didn't use red light or soak the film in anything. The photo was taken, and then you waited until the image was visible…
I know, questions upon questions and certainly completely wrongly explained and understood ^^ But, that's why I have you 🙂
Thanks in advance for your answers and stay healthy!
Greetings Sonic
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The red light is used because the photo paper in the red area has a sensitization gap. It does not respond to this red light. There is also an awareness gap in the yellow area, so that sodium steam lamps can be used. However, this does not apply to all photo materials. An example of this is the panchromatic films that are usually used for recording in the camera. Also colour material which should also be red or as negative material blue. Such material must be handled in complete darkness.
You also have a developer in the instant picture material. It is a paste in a small plastic bubble. When the film is pushed out of the camera, place this plastic bubble and the developer paste is distributed over the light-sensitive layer with the aid of the rollers through which the film is drawn. During the winding, either the later image carrier blocks the light or the developer paste itself. Dyes are released which diffuse to the surface and give the image.
Very detailed, thank you! Now I know why:)
It will be for him, the chemi is in the thick part of the polaroid and is pressed into the photo while the image is ejected. Since the chemical processes at Polaroids are never completely stopped, after a few years these images also change quite in color. Many old Polaroids have a brown/red color engraving.
This only worked with old orthochromatic black and white film, because it mainly reacted with green and blue light. The problem with this film was that he was terrible for skin tones. This is why panchromatic film is used today, and it can no longer be developed completely in the red light chamber, but only in a light sealed tank.
An instant image camera is already a less modern compared to the correct illumination.
The pictures that were shot at the time fell on the film and burned the picture in the film. (If the film had fallen out and/or hit light, the film was over). In the chemical process in the dark chamber the film was developed and no longer susceptible to the sunlight.
The red light also impairs the film a little (only not as strong as yellow or the like) so it was never very bright, just a little light you need to see what you do.
Immediate image cameras already develop the photos in the camera and small fun fact, you don’t have to shake the photos with modern cameras, which in no way affects the speed of development.
And technically correct isn’t what I wrote, I don’t know. But it fits. If anyone who has more idea what to complain about, please do not complain in the comments but supplement, thank you.
That’s right, Papa has always shaken out the photos wild ^^
What is a habit that has become natural, but it is not supposed to be done.
That was the light that had the least uv share.
UV light would have exposed the negative further.