We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Cleaning optical surfaces
You can clean a seriously stained or corroded surface by gentle polishing with a fine wet rag and a dab of rouge or cerirouge. This is a last resort of course, on a surface which would otherwise be discarded. Apart from this you should never, never touch a dirty optical surface with any solid other than a fine sable-hair artist's brush dipped in a suitable solvent such as analytical quality iso-propyl alcohol. The sweat on your fingers (which helps in fingerprinting) is acid enough to etch glass. There is never any reason to allow a cloth to touch an optical-quality glass surface, as it will almost certainly have abrasive silica particles embedded in it.
Camera lenses
Camera lenses are best kept with a permanent anti-ultra-violet filter in place. If it is necessary to clear dust, a blower-brush is the proper device. If the glass surface has stains or dried water-spots, then the solvent of choice is iso-propyl alcohol. Diethyl ether can also be used in a well-ventilated place and ethyl alcohol too, although it is not such a good solvent for lipids. Diethyl ether evaporates quickly and the consequent cooling of the surface may cause water-drop condensation in high humidity surroundings. Ethyl alcohol will dissolve water.
The basic rule is: don't touch and don't polish with a cloth.[…]
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
