The Care and Preservation
Even with today's dichroic colour changer and LED
systems, plastic colour media is still the most
popular method of providing stage lighting tint.
From basic weekend musical group lighting and disc
jockeys, through professional theatre, to the largest
touring rig, the ubiquitous "gel" still finds its place.
Here are some tips to assist the lighting maintenance
crew in getting the most life and greatest usage out
of these simple, inexpensive, coloured sheets.
INFORMATION BELOW MAY NOT BE REPRODUCED
WITHOUT PERMISSION FROM THE AUTHOR ©
Be aware that neither Atlantic Illumination, nor its owner or
employees will be responsible for any problems encountered as
a result of following or not following the procedures here. This
is strictly a guideline. You must decide the suitability of the
following and be responsible for the results of your work.
Colour media comes in a number of forms including gelatin, glass and various plastics such as acetate, polyester and polycarbonate. These are covered elsewhere at this website under Colour Media. This article will help you in using and caring for the plastic sheets coming under the blanket term of "gel". That name comes from the first "plastic" colour media; it was made from gelatin -- yes, the same stuff people eat for desert! For the purposes of this article, unless stated otherwise, most of the tips given here are for the typical polyester coloured sheets.
Most gel comes in sheets of around 500 X 600 millimetres and in larger rolls. One may sometimes buy smaller, cut frames from music stores. Regardless of the size, one should endeavour to store these sheets flat and in a dry and dark location. The dark is far less of a factor concerning modern polyester and polycarbonate materials because the tint is colour fast under ordinary conditions. However, prolonged exposure to sunlight will eventually lighten the dyes in even those materials.
It is suggested that uncut sheets be kept unrolled in a portfolio style of a large chest of drawers, preferably one drawer for each general gel colour, if one can afford the drawers and has the space. Otherwise, find a large shelf or table top where the gel can be stacked and where nothing is likely to be placed on top of it. The drawer, shelf or table should be at a height that allows one to easily view the corner labels that identify the colour name and number. It is recommended that you stay away from cardboard drawers. They don't operate well and bind too easily after a large number os sheets are inside. Whatever the method, be sure to employ paper separators between sheets to prevent them from sticking together.
Barring that, sheets can be hung on large hangers if clips are used. Don't drape the sheets as they will get a crease and are more likely to fall off during colour-number hunting. Even with the clips, marks will be left on the sheets. Fortunately, they will be on the edges where they will not cause deformation of the part that falls within the beam of the light. Cloudy or crinkled gel within a light beam can cause unwanted spill. It is also more likely to trap heat and thus shorten its life.
Be aware that the problem with the hanging method is that not too many sheets can be hung on clips before their weight will allow one or more to slip out and end up on the floor. So either use a lot of hangers or select a flat storage method. Lay the gel flat on a counter or table top when removing or adding sheets to the clips, and then hang it up immediately afterward.
Gel that comes in rolls is best stored rolled up. Typical lengths of seven metres generally precludes storing it flat. Even if one had the space, new rolls would have too much material to easily handle. Storing rolls horizontally means a shelf with sides to prevent them from rolling off and a depth of typically one and a quarter metres. Most lighting people simply store them vertically. Always leave rolls in their protective plastic coverings in which they are usually shipped.
Once cut into frame size, gel may be stored in an accordion file folder or a standard file cabinet. Use file folders or envelopes to categorise the colours and numbers, if you use a cabinet.
When you are working shows, it is good to carry a Colour Kit with you. Even if the show is already gelled, you'll need spares for burnouts and damages that will happen on the road, and also to be able to handle requests for colour changes. Get a sturdy suitcase, or actual road case, if you can afford it. Inside place the items listed in the above link.
In order to cut gel, it is best to have a flat table large enough to handle the sheet or roll. Screw masonite or wood to the top of it to handle the knife marks. If you cut rolls often, build a jig to hold the roll on a dispenser. Attach a metre stick on the edge of the table and designate a `zero' mark from which to measure. Have another metre stick made of metal to use as a straight edge and to measure in the other direction. Metal is preferred because the razor knife would eventually whittle down a wooden one.
Always cut slightly smaller than the frame size so as to ensure a proper fit without gel sticking out. This is especially important if you tape the sides of the gel frames shut. It is far easier to insert a cut gel piece into a frame when it is not rubbing the taped sides.
An exception to the "cut smaller" suggestion is regarding acetate and polyester gel. They tend to contract over time after exposure to high heat. Eventually they may shrink enough to allow a sliver of white light out. So to prevent that, cut these gels the same dimensions as the frame size and try to bind each tightly within a metal frame. Bound metal frames will help keep these gel types from buckling and contracting so easily.
A procedure that works well for sheet sizes of gel is to place a corner of the gel sheet into the frame and to cut around the frame with a razor knife or a gel cutter. The latter consists of a small, flat holder with a razor blade inside. One edge has an opening to expose the blade. One slides the cutter along the outside of the frame in the manner of a letter opener, cutting the gel to the correct size. To do this well, allow the frame side to extend over the edge of the table slightly. With one hand firmly holding the frame and positioned gel sheet flat, use one quick motion with the cutter angled up to skim along the edge and cut the gel in a single motion per side.
Once again, before cutting, place the gel slightly inside the frame so as to end up with a smaller gel cutout than the outside dimensions of the frame -- acetate and polyester gel types excepted. This will take practice to get the right technique. While learning, expect to bind the blade and to crinkle a few sheets.
Once gel has been cut, label it. This will help you to discern like colours. It is also a plus to a pickup crew that is unfamiliar with manufacturers' number designations, and is thus unable to associate a colour with a number. Even for the experienced, like colours can be hard to differentiate when un-numbered.
Use a gel pencil or china marker to put the number in the upper right corner outside of the frame's projection opening. Make it large so as to be readable in dim light. If you use more than one manufacturer's gel, place a letter in front of the number so as to distinguish one from another. Light colours can be labelled with a black felt-tip marker or black gel pencil.
Cut each gel in a manner that will make most out of a sheet. That is, don't cut four squares, one out of each corner of a sheet, leaving a cross in the middle. Cut each frame, one next to another. The left-over piece may not cover the frame size you just cut, but it could fit a pinspot or followspot colour pack, or be used in an internal colour wheel in a moving light or special effect. Even the little scraps can be used to colour flashlights, dashboard lights in automobiles, LED lights, and so on.
Photographers may want small scraps for photo flashes; artists may want them to produce other effects. The act of giving out gel scraps is always gotten back in good will, and when you or someone else uses them, it keeps yet more things out of the land fill.
If you must throw it out, please place it in a
plastic retail bag and send it to the recyclers.
Heat is the greatest foe of gel. Moving gel as far from a light source as possible and/or increasing ventilation will help. Following are some suggestions to that end. Be aware that these are not without consequences, chiefly regarding intensity reduction, and/or light spillage and dilution of colour. You will have to determine what is acceptable for your purpose.
- Choose fixtures that use heat-reducing lens coatings.
- Choose fixtures that use heat-reducing reflectors (cold mirrors).
- Choose fixtures that have long snouts.
- Choose fixtures employing open-edged gel frame holders.
- Use the farthest frame holder position from the light source.
- Clip gel to a snoot or barndoor to increase the source/gel distance.
- Punch pinholes into the gel.
- Place a heat filter between the gel and light source.
- Lower the lamp wattage.
- Use long-life lamps of the same wattage. They put out less heat.
- Reduce the dimmer setting.
What do you do with old gel? Most just throw it out, but in this day of frugal business concerns and trying to keep garbage to a minimum, here are suggestions as to what to do with it:
Again, if you must throw it out, please place it in
a plastic retail bag and send it to the recyclers.
It is possible to bring some gel back from the dead. As was discussed in "Old Gel", one can wash dirty colour media, but it is also sometimes possible to bring back hazy, scratched gel to a usable level. Those that have big budgets won't bother, but those without that luxury, persons that wish to be frugal, and those that want to keep as much out of land fills as possible, will strive to get the most life from their gel.
A good product that can rejuvenate dirty, scratched colour media is ARMORALL. After cleaning and drying the gel, put a small amount on and rub it in with a soft cloth. It actually reduces the diffusing effects of small scratches, and can often buff the gel back to usable life.
For really bad gel, evenly smear the ARMORALL on and leave it over night. The next day, wipe off the excess and polish to a lustre. Repeat for the other side.
Caring for colour media will ensure that one does not
have to order replacements sooner than necessary.
This permits money to be put into new stock, thus having
a greater variety for those times that call for that one odd
colour to complete a desired look for a particular show.
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