The GamColor CineFilter swatchbook measures 3.3 x 4 inches to easily cover your light meter. Each sample is provided with the key information you will need in a quick-and-easy-to-read format. Light loss is given in the nearest f stop and as a percentage. The quick reference chart shows how each filter alters the color temperature of a 3200Æ’ (tungsten) and a 5600Æ’ (nominal daylight) light source. Color shift (Kelvin temperature) is also shown for each CineFilter as well as mired shift. (For an explanation of mired shift click on Instructions.) The full spectral distribution chart shows each filterÂ¹s response to visible spectrum as well as near UV and infrared energy. Each page has a brief description of the filterÂ¹s function and application. The inside front cover is a handy white reference card, the inside back cover is an 18% grey reference card.
ND (NEUTRAL DENSITY)
ND Filters are designed to reduce the light output of your light source without changing the color temperature. ND filters are often used on windows to reduce the brightness and balance the contrast ratio of daylight to the indoor or shadowed area.
GamColor ND filters are available in five graduated steps providing for a light loss from 1/2 stop (.15) to 3 stops (1.2). See the convenient GamColor correction chart for your choices of GamColor ND and combination ND and CTO filters. GamColor ND filters are available in five steps: .15, .3, .6, .9 and 1.2.
CTB (Color Temperature Blue)
CTB filters are designed to increase the color temperature (measured in degrees Kelvin) of a light source. GamColor CTB filters will raise the color temperature of an incandescent light source to match the color temperature of a daylight source such as a strobe or HMI lamps.
Full CTB will typically convert a 3200 K light source to 5500 K, or normal daylight. Because incandescent lamps vary in color temperature and with the operating voltage, GamColor offers seven graduated steps of CTB filters to help you achieve the proper color balance. They are 1/8, 1/6, 1/4, 1/2, 3/4, full and extra.
When color temperature is very critical a color light meter should be used. The meter will give the color correction in “mired shift”. Refer to the convenient GamColor correction reference chart and select the GamColor filter closest to the mired shift suggested by your light meter.
CTO (Color Temperature Orange)
CTO Filters are designed to reduce the color temperature (measured in degrees Kelvin) of a light source. CTO Filters will lower the color temperature of daylight or a daylight source such as strobes and HMI lamps to match an incandescent light source. CTO’s are often used on windows to convert daylight to incandescent light.
3/4 CTO will typically convert sunlight at 5400 K to 3200 K typical tungsten. Because sunlight varies in color temperature by region and during the day from sunrise to sunset, GamColor offers six graduated steps of CTO from 1/8 to Extra. You can achieve the proper color balance and the color quality of your choice by selecting from these six steps of CTO’s, 1/8, 1/4, 1/2, 3/4, full and extra.
GamColor CTO filters are designed for color correcting HMI and strobes as well as daylight. Choose the correct filter by using the convenient GamColor correction reference chart. In order to use the chart you must know the color temperature of your light source.
When color temperature is very critical, a color light meter should be used. The meter will give the color correction in “mired shift”. Refer to the convenient GamColor correction reference chart and select the GamColor CTO filter closest to the mired shift suggested by the light meter.
CTO/ND (Combination Neutral Density & Color Temperature Orange)
CTO/ND filters are designed to both reduce the light level and decrease the color temperature of your light source (See notes on CTO and ND filters). GamColor CTO/ND filters are most often used on windows where strong sunlight must be reduced in intensity and corrected in color temperature to match incandescent lights.
GamColor CTO/ND filters are available in three steps .3, .6 and .9 each combined with full CTO. See the convenient GamColor correction chart for your choices of GamColor ND and combination ND/CTO filters.
MINUS GREEN (Fluorescent & HMI Correction)
Minus green filters are designed to reduce the green spike found in fluorescent and HMI light sources. Minus green filters can be combined with the CTO or CTB filters to simulate the desired color temperature. GamColor ND and combination ND/CTO filters.
GamColor Minus green filters are available in six steps to deal with the many types of fluorescent lamps and the fact that the green peak increases with the age of an HMI lamp. You can choose from 1/8 Minus green through full Minus green. The six steps include 1/8, 1/4, 1/2, 3/4, minus green and extra minus green. Where color reproduction is critical use your color meter to determine the GamColor Minus green filter required and refer to the convenient GamColor correction chart.
Using PLUS Green Cinefilters
Plus Green CineFilters are designed to be added to sources being used as fill lights where there is a predominance of fluorescent lights that cannot be eliminated. Fluorescent light sources have a very high green peak and therefore it is often necessary to correct the film or to adjust the video system to eliminate the green. Since fluorescent fixtures are usually mounted to the ceiling filling large areas such as a supermarket with light, it’s hard to avoid them. Turning them off would leave great masses of black holes.
Plus green filters will reduce the red and blue output of the light source, thus creating a green spike simulating the fluorescent lamp. By adding plus green filters to incandescent and HMI lights used to augment the predominately fluorescent lighting they can simulate the fluorescent light. The resulting photography is then corrected in the lab where the “green” is eliminated. This approach is not the best solution for color quality but offers a fast fix to shooting color under fluorescent lamps.
Plus Green GamColor CineFilters can also be used in front of HMI lights that are being used as fill lights where mercury vapor or fluorescent lights are in use.
Large windows which have ultraviolet filters imbedded in them often have a distinct pink shift. When this happens you can use the 8 Plus Green filters on the windows or in fill lights to help balance this pink shift.
Another interesting application of Plus Green filters is to make plants in the background of a shoot look a little richer. Plants in the background of a shot very often look dark and dismal. By using 1/8 or 1/4 Plus Green GamColor CineFilters you can bring out the green color of the plant life.