making the grade

curve mapping exposure to various grades of paper. from Basic Photography by M J Langford 1965

Toronto. This post refers to film (black and white)  printing. Once you choose the huge number of variables for a photographic paper choice, you are left with one last factor – paper grade.

Ideally, the chart shown at left (3 grades, but some papers go to 5 or even 6 grades) shows how the negative printing exposure (exp.) maps to the paper using different grades. If it was only that simple a choice! Paper surface type, illumination type, grade, etc. all affect the final contrast on the paper. Ilford and other big manufacturers came up with double coated papers. One coating was very low contrast, the other very high contrast. Filters gave an exposure in various ratios of the two emulsions allowing one package of paper to cover a full range of paper grades from soft to hard.

The dynamic range from dark (shadow) to light (highlight) in the eye is very great. This range must be compressed in the film and crunched even further in the print. Film sensitivity and developing process affect the scene contrast. Basically the slower the film, the greater the contrast (and finer the grain). If a film is under-exposed or developed, the result is a very thin scene (flat). A contrasty paper grade may help a bit but shadow detail must exist for the print to show it. Alternatively, an over-exposed or developed film (negative) makes for a very dense scene. A softer paper grade (lower number) may help but once again detail must be in the negative or the highlights just block up on the print and show a flat tone.

Lots of books were available in the latter half of the last century to show how to properly expose and develop a film and the properly print each scene so there is some detail in both shadows and highlights and the over all contrast is from very light detail to very black (dark) detail. Not an easy task. It takes hours of study and experiment to get it right technically. Then you are stuck with the real artistic effort entailed – lighting, scene, framing, mood, etc., etc.

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