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The results of the error in estimating the exposure factors

We can divide the error in estimating the exposure factors into the following:

(a) Overexposure

As a result, the details of the high lights, light colors, or white areas of the photographed subject disappear, or at least become less clear, while details appear clearly in the shadows or dark areas.

(B) Underexposure

As a result of this defect, the clarity of the details in the shadows areas decreases, because the exposure was not sufficient to record the details of the shadows areas on the sensitive layer, or the details of these areas may completely disappear.

A simple error may not affect the value of the image. Assuming, for example, that the exposure factor should have been 8 f with a shutter speed of 1/50 of a second, then the photographer made a mistake of 8 f with a speed of 1/25 of a second, then the value of the image will not decrease very much. As a result of such a simple error, and this is due to the progress in making sensitive films (black and white) and the improvements that have been made in their manufacture (1), however, there are films (such as color films) that are greatly affected by such an error, and therefore it must be appreciated Exposure is very correct. It is possible to fix the simple error in estimating the exposure through the exposure process by increasing or decreasing the exposure time according to the type of error, and it is also possible to fix it by printing or enlarging the negatives on high or low contrast sensitive paper or by means of other chemical operations that can be performed after showing the film The lack of exposure can be repaired chemically by the process called Intensfication, ie increasing the density (sometimes called the process of strengthening). An error caused by overexposing can also be fixed by a reduction process called ReductionProcess.
There is a traditional rule known among photographers that
“In case of doubt about the estimation of the two exposure factors, it is better to consider increasing the exposure rather than decreasing it.” Practical experiences support this rule.