This section is from the "Studio light a magazine of information for the profession 1915" book, by Sara F. T. Price. Also see Amazon: Studio light a magazine of information for the profession 1915.
There are a lot of photographic troubles that come on us so gradually that they escape our notice until someone on the outside brings our attention to them. For instance, if I were coming into your studio this afternoon to make a demonstration of plates, I would not ask you if your lens was clean - I would look, for myself, and see. You probably do not realize it, but if that lens has been in your camera all summer and has not been carefully capped, its surface has in all probability become dulled, and this condition has affected its rapidity.
If such a condition does exist, it has come about so slowly that you have not noticed it. Yes, we have mentioned this same thing in Studio Light before, but it bears repeating.
It is an easy matter to damage a lens by cleaning, and it is not possible for a photographer to repolish its surface once it has been dulled by scratches. If the lens has a smoky appearance - has gathered moisture and a certain amount of dust, the first thing to do is to take it out of the camera and dust the surfaces with a camel's-hair brush to remove any dust. Then wipe each surface carefully with a soft, dry linen handkerchief. If the surface still appears cloudy, a single drop of pure grain alcohol should be put on each of the surfaces, which should be wiped until quite dry. The alcohol must not be allowed to run between the lens and its brass cell, and care must be taken not to remove any of the black coating from the lens cell. The edges of the lens next the cell are best cleaned by the pointed end of a soft stick, over which the handkerchief has been stretched.
Never clean the surface of a lens with water, and if moisture from any cause ever condenses on your lens, remove it as soon as possible.
Once your lens has been thoroughly cleaned, do not put it in the camera until you have first dusted out the inside of the bellows. Every time you draw out the bellows to focus, there is enough suction to draw dust into your camera, and moving the bellows back and forth stirs up any dust inside the camera to such an extent that it would look like a miniature sand storm on a desert, could you see it in a strong ray of sunlight.
When you have finished focusing you have this dust all in a whirl. You quickly insert the plate holder and draw the slide.
FROM AN ARTURA IRIS PRINT
By Theo. Ragu St. Louis, Mo.
Then you take your time to making the exposure, while the dust settles down on the four sides of the bellows and on the plate. Then you wonder why your negatives often have fine transparent specks on them that look like the marks of dust, but you are sure you dusted your plates, so it must be in the emulsion.
Mind you, I am not saying this ever happened to you, but you may feel better to know that the trouble you take in keeping the inside of your camera clean has really been worth while.