What is the principle of developing photos in darkroom? What kind of lights should be used in a darkroom to avoid exposure?

The first chemical solution (developer) will develop the irradiated area into black silver particles. The second liquid medicine (fixing solution) used later can dissolve (fix) the silver halide in the unexposed part, leaving a transparent film.

Therefore, chemical by-products are washed away, and the washing result obtained after drying is a black-and-white negative.

Because the photosensitive material is mainly composed of silver halide sensory chemical elements, it is sensitive to daily light sources, but insensitive to orange-red, that is, orange-red is like darkness under this drug, but human eyes can see the outline of objects under orange-red. Therefore, the use of such a light source is conducive to darkroom work.

Although digital cameras are very popular, ordinary cameras still occupy the main position. If you use digital ones, there will be no negatives and there will be no problem of going to the darkroom.

Extended data:

Layout method

First of all, it is easy and important to have a table big enough in the darkroom so that common equipment can be easily accessed on the table.

Then, in the darkroom, chemicals such as developer are usually concentrated to form wet areas, and articles that need to avoid water are concentrated to form dry areas, which can reduce the probability of accidents. An accident in a darkroom does not mean a dangerous accident to safety, but many of our beloved works are equally annoying if they are damaged in the darkroom, even if the film is damaged.

Secondly, adding safety lights with different brightness is a better way to monitor the washing effect.

You can also add audio equipment to the darkroom according to your personal preference. In addition to maintaining a happy mood when developing photos, the inspiration of music may enable us to achieve unexpected development effects.

Baidu encyclopedia-darkroom