Sheet-shaking and cleaning the insides of light bulbs

<p>I am frequently reminded that much of the photographic information in my brain is obsolete and completely useless. Do the 2 activities in the headline mean anything to anyone apart from me?</p>

<p>Though I have not heard either of the two, I think I have a pretty good guess about the first one and would take the second by its literal meaning, cleaning the white (kaolin) off the inside of light bulbs that are to be re-purposed for a different use.</p>

<p>Now hoping to be educated about the real meaning so I can add it to my stash of useless information.</p>

<p>Probably not what you're talking about, but in film production, the grips will say they're "shaking up" the reflector 'shiny boards' to correct the lighting when the sun has moved.</p>

<p>Please enlighten (!) us, David - I have always been a collector of arcane knowledge, both for my own interest and to bamboozle and perplex others.</p>

<p>Tony</p>

<p>Thanks for your responses guys! Obviously a word of explanation is in order:<br>

Sheet-shaking. It was (and a certain extent still is) common practice to present images of technical products in blocked-out form, i.e. with all the background removed. It was easier to do this if white sheets were hung up behind the machine or product in question during photography. Inevitably these sheets would not be perfectly smooth and might even have marks or small stains on them. Since this kind of photograph almost always required a very small aperture for maximum depth of field and a correspondingly long exposure, it was possible for industrial photographers to have lowly assistants stand behind the sheets while exposures were made and shake these so that all detail in the sheets was blurred and a uniform smooth white background was obtained.<br>

Cleaning the insides of bulbs. This is a particular favorite of mine, since telling someone to do this at first hearing seems on a level with sending them to fetch some checkered paint or left-handed nails. It was, however, a genuine and legitimate activity. When color photography came into the movies, sets were lit with incandescent bulbs with a GES (giant Edison screw) fitting. These bulbs had quite a long working life, but soot tended to deposit on the inside of the glass envelopes, reducing both light output and color temperature (making light more red). To counteract this, a handful of ball bearings, around eight or 10 in number and 1/8"/3 mm in diameter, were placed inside each bulb during manufacture. It was then possible to unscrew each bulb from its socket, hold it with the cap uppermost and swirl the ball bearings around on the inside of the glass envelope, thus cleaning this.<br>

I have not personally done any sheet shaking but worked for two years in my youth at the V&A Museum in London, which had negatives going back to the 1860s, some of which had been produced using this technique. I have also heard several old-time photographers describing how this was their first task as a photographer's assistant. The bulb cleaning I have done myself, since I started my studio career before incandescent bulbs had been completely replaced by strobes.</p>

<p>Boy, was I off on the sheet shaking: http://www.urbandictionary.com/define.php?term=shake+the+sheets</p>

<p>I've never seen a filament bulb with BBs in it, and I've been around quite a while. I have several spare GES 1Kw filament bulbs for an old Kennet "Beauty dish" - from before anyone invented that stupid name for an oversized ringlight. Boy, have I seen some ugly pictures taken with a beauty dish.<br /> Anyhow, none of my monster 1000 watt bulbs have any BBs in them. Not even a bit of lead shot. However I vaguely remember some theatrical bulbs having a sand-like substance rattling around in them once upon a time.</p>

<p>David, thanks for reminding me about sheet shaking. I was once aware of the technique but had completely forgotten about it. It's another long-exposure technique to bear in mind, like blurring moving water or getting rid of moving crowds of people.</p>

<p>On reflection I'm surprised no-one has marketed a sheet-shaking machine for air-headed fashion photographers to add to their armoury of gimmicky studio props.</p>