SOME TRICKS WITH COLOUR MEDIA
| There are a number of tools at our disposal to create colour effects.. Mostly we use the generic title “Colour Filter” “Media” or even “Gel” ( although the original gelatine medium has not been made or used in living memory) |
| When you dim down a halogen lamp, it tends to shift towards the red end of the spectrum, and it is really quite difficult to achieve a cold dim light. At one time, smaller wattages were available for profile luminaires but now they are hard to find. The fix for this is to double up on the colour, i.e. two 117's or 161's together. However, if you put them in the same frame, they will tend to melt together and bleach out quicker, so the effect is soon lost. If you put them in separate frames in the same luminaire, that problem will be solved. |
| Another piece of received wisdom was that lavender No 136 made elderly actresses look like blushing teenagers. Take it from me, it didn't, but the actresses in question firmly believed in it and often had it written into their contracts. Francis Reid describes a quick fix which involved putting some meaningless float spots in to the dark scenes with gels with the legend "NO 136" written in very large letters in chinagraph and kept at low check to keep them happy and believing in their own youthful bloom. |
| Colours can be mixed and matched to create a variety of unique looks. At one time it was received wisdom that if you put two circuits of 143 ( deep navy) and one circuit of 103 ( straw) in the battens, you could achieve any shade of daylight you needed, which you could then supplement with sun keylights and soft fill as required. I never tried it personally. (Talking of battens the best one ever at one time were the fluorescent dimmable battens at the Grand Theatre Swansea - they are long since gone. Bright as hell and amazing saturated colour, but by God they were noisy). |
My favourite colour of all time was Strand Electric's No 8 ( a violent fluorescent amber colour). I used to lovingly care for every scrap I could find when it was withdrawn from the market on the (to me) specious grounds that it was radioactive and cancer forming. Pah! what did I care for that? It made the most fantastic candlelight colour ever, especially if used in combination with No 47 ( almost but not quite the same colour as the later No 147). Many is the time I carried it up the tallescope in my mouth and (cough) it never did me any harm. I still have a piece in the shed. I wonder if I could find it in the dark? |
| I once attended one of the legendary lectures given by Fred Bentham in which by means of dextrous colour media swapping and a running commentary has the bemused audience completely confused as to whether a colour we thought was green was in fact a pale violet when viewed next to a deep blue. It is my ambition to reproduce this lecture one day. Watch this space. |
| Make a tapestry gel- small roughly torn pieces of selected colour scroller-taped or stapled to a sheet of clear filter in the colour runner of a Fresnel makes a superb dapple or stained-glass effect when used as a backlight with a little haze. If the edges are torn or cut unevenly it works better |
| Also on a Fresnel, split the colour vertically or horizontally to create well-defined areas or stripes of colour from a single luminaire. Cut a small round hole in the centre of a filter to provide a facelight with a coloured halo. |
With a profile: Split colour gives very generalised colour effect rather than a well-defined one, while making interesting variations on colour texture across the beam. Its a very good way of creating e.g. a cold sun effect with a straw split with a cold pale green horizontally. A hole cut in the centre of the colour filter tends to pastelise the entire colour effect. |
| To light a staircase or make a well defined path with fairly soft edges, try using a fresnel, focused wide with a piece of Rosco 'spreader frost' or Tough silk which spreads wide in one plane but not the other. |
| If you cannot get your coloured floods far enough away from the cyc, use the coloured Cyc Silk, which will help remove the scallops and blend the edges. |
| A combination of a half-colour ( i.e. a strip of colour in an otherwise open white frame) will give great fractured colour effects with a gobo. |
Some technical stuff about filters
PLASTIC MATERIALS
We are most used to using one or other of the flexible plastic types, of which there are a number of manufactures making a huge range of colours . Polycarbonate is very tough and has excellent heat-handling properties but certain colours and tints are difficult to produce. Polyesters are easier to dye and have good heat-handling qualities too. Both types are self-extinguishing.
There are three basic technologies, surface coated, dye diffused into the material, and deep dyed. Many claims are made for the relative merits of each, including longevity and colour bleaching, but the manufacturing techniques of the more reputable manufactures are now so good that the difference in practice is not very great in the short term. In the longer term, colour bleaching is definitely a problem.
(illustration copyright Roscolab Ltd)
However one thing is quite important: when used in high temperature fittings, it is necessary to use the HT (high temperature) versions where available or to insert a piece of heat shield between the colour and the lens. The shield needs to have an air space on both sides of the filter to allow an escape for the convected heat. Do not sandwich two filters together in one holder. This will cause premature failure of both filters. There are two types: a clear plastic which can take an operating temperature twice that of Polycarbonate or polyester, but does not block the infra-red energy: and a special proprietary material which has a vacuum- deposited multi-layered coating designed to reflect the infrared energy that destroys color filters.
Colour numbering across manufactures tries to follow a standard numeric system, but this can be a little illusory and sometimes fails altogether. Manufacturers produce equivalence and substitution charts
GLASS AND OTHER MATERIALS
There are other more modern and more expensive colour media materials. One of the most versatile is the dichroic filter. This is made by vacuum-depositing between 20 and 50 separate layers, approximately one one-thousandth of a millimeter thick of light refracting material onto a very thin flat piece of glass that has low thermal expansion properties.
Where standard gel filters absorb the unwanted wavelengths and dissipate them in the form of heat, dichroic filters work by separating out unwanted wavelengths by refraction and reflect them away while passing the desired colour. They are quite expensive to produce and have size limitations at present. However they last much longer without degradation, melting, bleaching out, scorching, etc, and produce a brighter, more saturated cleaner colour.
Because of their characteristics of reflecting different wavelengths (i.e. colours) at different angles, diccroics can form the basis of very versatile colour change systems.
Devon Glass
This is a true dyed glass filter, with some beautiful warm deep colours, especially reds and blues. There is very little fading or colour shift over time. The glass is cut into strips to allow expansion and bound in a frame. It is possible to combine strips of different colours into on frame. At present sizes are limited to about sixteen inches. Sometimes the colour varies however, and the units will not stand sudden changes in temperature., so outdoor use is impracticable.
SPECIAL PURPOSE MEDIA-or: Answers to various prayers.
NEUTRAL DENSITY FILTER
This is the answer to the particular prayer of how to get a really cold really dim light. This stuff looks like a normal grey colour effect filter, but has a very different function. It is effectively a “dimmer gel,” which can cut down light transmission by anything from half a stop (69 %transmission) to four stops (6% transmission) or more, by combining various grades without (theoretically) altering the colour balance too much). When you dim a halogen light it inevitably becomes redder, which makes steel blue very muddy and dirty, With the use of the magic neutral density filter, this problem vanishes. Our cold dim light can be achieved with a 1k fresnel at full with two layers of 117 and one or two pieces of three-stop.
Other uses include making anything from a fluorescent or an HMI to a video projector less bright.
It is also available as an adhesive backed filter for windows, easy to use, easy to install and easy to remove. It allows you to simply cut the intensity and change the colour temperature of light coming through the window
DIFFUSION MEDIA A.K.A. “FROST”
Can’t quite get your pathetically limited stock of luminaire to quite fill the stage? Do you get that annoying flicker on the actors face as he walks from prompt to OP? Only one lamp to light a whole staircase? Is your sunshine just too sharp? Blotchy cyc?
What you need is diffusion
There is a huge range of diffusion products available to solve virtually any problem.
The table below (published by kind permission of Roscolab Ltd) gives you some idea of the range available from just one of the manufacturers.
100 |
Frost |
Changes ellipsoidal to fresnel beam pattern. |
101 |
Light Frost |
Offers softened beam. |
102 |
Light Tough Frost |
Changes ellipsoidal into flood or scoop. |
103 |
Tough Frost |
Has twin qualities of wide diffusion and warm center. |
104 |
Tough Silk |
Creates a slash of light for stretching light along stairs, tables, cycs, etc. Diffuses in one direction (at right angles to the direction of the etched lines on the media) while maintaining compactness of beam. |
105 |
Tough Spun |
Good on scoops for cyc lighting. |
106 |
Light Tough Spun |
Removes lens shadows. |
111 |
Tough Rolux |
Densest diffusion of the series. Spreads the light almost 1800. |
112 |
Opal Tough Frost |
Lighter than 100-103. An excellent diffuser for HMI, CID and CSI sources softening the beam slightly while maintaining excellent transmission. |
113 |
Matte Silk |
Good for striplights and specials. |
114 |
Hamburg Frost |
A very light frost; good on followspots and PAR lamps. |
116 |
Tough White Diffusion |
A range of diffusion materials adapted from cinematography-used for softening the shadow of the beam while maintaining a relatively high color temperature because of the use of "ultra-white" pigments in the manufacturing process. |
117 |
Tough 1/2 White Diffusion |
|
118 |
Tough 1/4 White Diffusion |
|
119 |
light Hamburg Frost |
Lighter than 114. Recommended for followspots and slight diffuse focus for profiles. |
120 |
Red Diffusion |
Combine a color with Matte Diffusion. Aids in broad, even illumination of cycs and drops. |
121 |
Blue Diffusion |
as above |
122 |
Green Diffusion |
as above |
124 |
Red Cyc Silk |
Colour combined with 104 Tough Silk. Useful in border and striplights to prevent scalloping; helps illuminate cycs and drops. |
125 |
Blue Cyc Silk |
as above |
126 |
Green Cyc Silk |
as above |
127 |
Amber Cyc Silk |
as above |
150 |
Hamburg Rose |
Combines Hamburg Frost with 05, a color flattering to skin tones. |
160 |
Light Tough Silk |
Retains the diffusion properties of 104 but with less light loss. |
162 |
Light Opal |
A lighter version on the 112 Opal Tough Frost. |
163 |
Powder Frost |
A good medium cosmetic diffuser. |
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