# Tag Info

5

The images on gelatin-silver film and prints are formed by silver particles. The images on color (chromogenic) film and prints are formed by color dyes. There are also chromogenic black and white films that are developed using the standard C41 color process, but use black and white dyes to form the image. Modern commercial chromogenic and silver-gelatin ...

4

Let's take a look at the mathematics behind An paper sizing. The aspect ratio is r = w/h where h is the longer side. Now you want e.g. A1 to be half of A0, so the aspect ratio is r=(0.5*h)/w We have the equation r = w/h = 0.5*h/w = 0.5/r or r^2 = 0.5 Then r is simply square root of 0.5 or in other words 0.70711. Thus, the width (shorter side) is 0.70711 ...

3

Cameras of that era accepted film that was slightly larger than the delivered prints. Work was done in a dark-room. Since both the camera film and the print paper were sensitive only to violet and blue light, work was performed under quite bright red light. Red light is void of violet and blue. The film was immersed in a series of chemicals and the results ...

2

Because the standard is based on the square root of two — an irrational number — but each size is rounded to the nearest whole millimeter. The standard also allows for slight variation from the nominal number. In both theory and most practical use, A1 is exactly double A2. If you need precision beyond that, you should cut your own paper.

2

If you develop colour RA4 paper in black and white chemistry, you will get a faint black and white image, but it will appear very bright and with a very low contrast. Colour paper also contains a small amount of silver, which will react just as the silver in black and white paper when developed in b&w chemicals, but not enough to create proper, dense ...

1

It is possible to print color negatives and color slides on color photographic paper. However, It’s unlikely that high quality black & white prints will result. As previously stated --- Chemical based black & white prints yield monochrome images that display appropriate contrast and neutrality. Color photo papers display an images from imbedded ...

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