For those assisting cinematographers and dealing directly with various lighting directors both in theatres and movie studios, choosing the right gel filter and getting the perfect color temperature they needed for their production projects can be a real challenge. (Whoever said perfection can’t be achieved should look to professional lighting directors for some tips.) They often end up checking color swatches from various vendors who commonly publish transmission coefficient or spectral transmittance curves for each color gel in dozens of swatch catalogs. It can be a nightmare just finding the right one from all these printed materials.
But now all these are available in Wynbron’s Gel Swatch Library which has been around since its first iPhone release in 2009. With the spectral energy distribution curves coupled with the CMY/RGB content for each gel color, you have the vital information needed to achieve the stunning scenes in your mind right at your fingertips. Simply specify the manufacturer and browse through their color swatches or specify a gel name in the search feature.
The application gets better with its latest iteration in the Gel Swatch Library HD. Apart from the practical features of its precursor, the new version has a project function which is great for putting together all the color gels used for each of your theater or movie productions. There are also new functions like the HSL color picker, filterable searches and access to measured color transmission data right in the graph view.
When you launch the app on the iPhone, the first functional page is a color choice page with the HSL picker that should look familiar when specifying colors on a PC. Picking a color shows a list of available gels from among the nearly one thousand gel colors from GAM, Apollo, Lee Filters and Rosco.
Selecting from the list brings you to the detail view where the color swatch is displayed, its transmission value in percentages, color CMY and RBG content in percentage, the SED (Spectral Energy Distribution) curve and similar color shades available across all the manufacturers in its database.[nggallery id=1]
The app allows you to compare any two shades of the same color, or complementary colors to get the precise color information you need to get your desired photographic or cinematographic results.
What makes the application really useful is its precise comparison window between colors of different shades from the same or different manufacturers. This is helpful when you want to get the precise color filter to achieve the correct daylight color temperature to match your cam’s white balance when using tungsten lighting in a scene.
For instance, you can compare two deep blue colors from two manufactures and the comparison detail view shows up after specifying the name either in a filtered search or picking from the list. The screen shows the two swatches and a non-detailed SED curve along with the list of similar shades of blue and the complementary colors.
The SED curve can be quite informative. The horizontal axis is just the color spectra expressed in wavelengths from 400 to 700 nanometers while the vertical axis tells you how much of the color energy is transmitted when using the gel. The app allows you to compare the curves of two colors and in this case, the Deeper Blue gel from Lee (L086) and Rosco (R85) show the variation in the SED curve of each color shade.
The comparative curve tells you that the Lee Deeper Blue transmits around 30% of the blue energy content while the Rosco Deep Blue transmits 8.8% more. What that means is that you can precisely correct studio tungsten light to have a closer match to the daylight color temperature of a film negative.
All in all this is a really useful bit of kit and certainly something to add to your list of pro apps regardless of whether you’re a budding or seasoned cinematographer. Gel Swatch Library HD is available now on the iTunes Store
Have you been using DoF Viewer on the job? If so then we’d love to hear about it in the comments below.