A few weeks ago I had the good fortune of being exposed to the new line of deep dyed gels from Rosco Labs – CalColor gels.  These gels are actually a system for color filtration of lights that work in conjunction with motion picture film emulsions.  For years we’ve had camera filters that are precise.  Now we have filters for lights that are precise.  This doesn’t sound like much, but I know there’ve been many times I wished I had a cyan filter for a particular application, or a clean yellow with no hint of green in it.  Now it exists, and I know it will photograph.

 

    The colors now available are:

Red   Green   Blue   Cyan   Magenta   Yellow    

 

    The densities Rosco has manufactured are .15, .3, .6, and .9.  Sound familiar?  15 Blue, for instance enhances the blue layer of the film by ½ stop.  Simple.  The 30 Blue enhances the film 1 stop, the 60 Blue is 2 stops, and the 90 Blue is 3 stops.  Rosco’s had the wisdom to work their CalColor system into an existing standard the Director of Photography already uses.

 

 

 

 

    Although this test was rudimentary compared to what Rosco Labs went through in their testing, I was amazed to see the Vector Scope’s precise response to these gels.  Later I white balanced the camera with a gel over the lens.  When I removed the gel, the Vector Scope shifted an equal distance to the complementary color – also in the color coordinate box.  The complimentary colors indicated with the gel over the lens matched the correctly white balanced camera with the “real” complementary gel over the lens.  In simple English, the Vector Scope indicated the same position in the coordinate box with a clean lens, a “neutral” white balanced camera, and a 15 Yellow gel for example, and the camera white balanced with a 15 Blue gel.  I tested all of the colors.  It was an impressive performance.

 

 

    Think negatively.  This is the time to go against the grain about negativity.  The 90 Blue reduces the Red & Green layer by 3 stops.  Most cinematographers (including myself) may initially think that the 90 series of gels reduces light output 3 stops, like an ND (neutral density) filter.  Although this is a convenient way to think of how the gels work, it’s not entirely accurate.  Reducing a film layer’s corresponding densities by one, two, or three stops does not necessarily reduce the light source the gel is placed over by one, two or three stops.  Putting two opposite gels of equal number does work as an ND since all colors of light (wave lengths) are affected.  And, the color temperature is relatively constant if you do this.  Or you can make your #85 filter out of 60 Red and 30 Green!  I don’t know what value there is to that, but the fact that it’s possible tells me something about the precision in testing and manufacturing process.  This system can change your perspective about light and color, and what colors of light make a rich and full image come alive.

 

 

    I shot a short film test on 5293 with myRTVF-357 Advanced Cinematography class at CSUN.  Because of time limitations, we only filmed four different combinations of filters in all four densities.  The lighting was fairly simple.  The subject faced the camera.  He was keyed from ¾ camera left and 1 stop over the T/Stop on the lens (N+1 in the Zone System nomenclature).  The fill was slightly off the lens on the camera right side.  The fill was N-1.2 – but as we all know, at that angle the light is much more intense.  These meter readings are all based on the lights with no gels.  Once we started putting gels over the lights, the only area I metered was the cheekbone on the key side.  I kept this area constantly at N+1 and adjusted my exposure accordingly.  All exposures were printed at the one L.A.D. print light, as is my procedure.

 

    The combinations we used were:

 

                 KEY                                                 FILL                                 BACK LIGHT

               Green                                                Blue                                         Red            

             Magenta                                             Cyan                                       Yellow

               Green                                                Red                                    Magenta

                Red                                                 Cyan                                        Blue

 

    I shot a “normal” shot, one without color for comparison – a control shot as it were.  On each set up after that, we started with the “15” series and moved through the “90” series.  I didn’t mix densities within the shots figuring that the “big” effect would be more noticeable with larger shifts in color.  That certainly turned out to be the case.

 

    The first combination of green and blue with the red back light was very interesting.  The subject, a blonde Caucasian male with a light beard, has a reddish cast to his skin.  The 15 densities neutralized the red cast.  In the 30 density his beard took the green color, while his face remained relatively “neutral.”  At the 60 density, he took an underworld appearance – but not very intense.  At the 90 series, it was quite pretty.  The green was saturate, but not overpowering, the blue was the same.  And the back light held the feeling of red.  The look was something like I would expect on a submarine, or perhaps a horror shot.

 

    The magenta, cyan, and yellow combination was also interesting.  The magenta brought out the red in the subject’s face, but not so much that it bloomed.  The color is saturate, dense, and clear but not at all muddy.  The last series of shots, the red key, cyan fill, and blue back light was wonderful.  The red and cyan are complimentary and cancel each other where they both fall.  Of course the fill is about 2 stops less, so the cyan’s affect is proportionately less.  The red on the face is clean and full with the cyan shadow appearing interesting and shadow like – not just dark.

 

 

    If you want the most acute expression of Blue, Cyan, Green, Yellow, Red, or Magenta without over exposing the corresponding layer, then you should use these gels.  You can get more saturate colors with party gels, but you also run the chance of “blooming” an emulsion layer.  And what is “blooming” an emulsion layer?  That’s the overexposure of one layer on the film’s emulsion.  The layer most often abused is the red emulsion.  I often see shots where the reds “bloom,” while the rest of the image is dark, like in a bar scene.  The over all density of the film may be thin while the density of the red layer is at it’s Dmax.  At that point it begins to “bloom” into the surrounding emulsion.  It’s interesting if you think about it, a dark image with a maxed out layer “blooming” into the surrounding image.

 

    If you want to match a color exactly to the source, these gels provide the tools to get fairly close fairly quickly.  I’ve used Y1 with Rosco ½ CTS to emulate candle light.  It’s not bad.  Now I can match candle light exactly with a 15 + 60 Red gel and a 30 Green gel.  Or I can make an artistic expression of another color temperature, or combination of gels, that feels better in the scene.  These gels provide more opportunities to make positive color choices.  They can help the Director of Photography better express his artistic decisions.

 

 

    The simple answer is, no.  Although when one uses HMI’s, one has to confront the reality of the difference in the age of the bulbs and the resulting color temperature shift.  Other factors like dirty fresnels or dirty or misaligned mirrors contribute, but the main factor is the age of the bulb.  The second aspect of filming with HMI’s is to determine what color temperature “day light” is.  In many ways this is a subjective question.  What I do, is to determine the L.A.D. of the film, decide the color temperature I want to expose for the “look” I’m after, then meter with a color temperature meter the filtration in front of the lens in the lighted environment.  It sound compulsive.  It probably is, but I don’t have many acuity surprises, or matching problems.  The diffusion on the lens (if any) is constant in its effect also.  With tungsten, the questions are the same, but without the ever changing outside environment to consider along with everything else.

 

 

 

    Color is the visual effect resulting from the eye’s ability to distinguish wavelengths of light.  For the Director of Photography, color is not only the physical effect on the eye, but the chemical effect on the film, or the electrical effect on the CCD, and more and more, the results of both.  The Director of Photography needs to interpret color not only in terms of the present moment he works, but in relation to it’s representation in the medium at hand.  With experience and testing he understands what he perceives is not necessarily what the film records.  And ultimately, it’s his taste and expertise that shapes his expression with color.

 

    Rosco Labs has made a great improvement for the Directors of Photography who desire to mix their own colors with primary and/or secondary colors’ who want to expose a particular emulsion layer; or who need to complement special effects with specific color light a specific colored object.  There are a lot of possibilities with this calibrated color system of light gels.  In fact, there appears to be more control in this system than the average cinematographer will know how to exercise photometrically.  But the average cinematographer will know what s/he likes represented on film.  That’s why these filters will be a hit.

 

            Mark Woods