Today’s Question: Did you happen to find a way to match Wratten numbers with HEX numbers or RGB values? For example, what is the HEX code of an 81A warming filter?
Tim’s Quick Answer: While I’ve not determined the specific color values of the original Wratten filters, you can get an approximate color value for some of them using the Photo Filter adjustment in Photoshop.
More Detail: Today’s question was a follow-up to an old article I wrote about fifteen years ago on the subject of photo filter effects with digital processing. In Photoshop, that means using a Photo Filter adjustment layer.
The Photo Filter adjustment in Photoshop provides the ability to add a color tint to an image, enabling you to mimic the behavior of some of the colored filters that were often used in film photography. In fact, some of the presets for the Photo Filter adjustment represent approximations of the effect from some of the standard warming and cooling filters.
You can also select any color you’d like from the Color Picker when using the Photo Filter adjustment. Start by selecting the desired preset from the Filter popup. For example, you can get a warming effect with the “Warming Filter (81)” option. This will change the color of the color swatch associated with the Color option, and you can click that color swatch to bring up the Color Picker dialog, showing you the color values for the filter you selected.
I have discovered that there is a slight problem with some of these presets, in that not all of them use proper color management. What that means is that for some of the filters you will get a different color depending on which color space you are working in. The differences are not too significant, however.
So, you can use this technique to determine Photoshop’s version of the color you would apply to achieve the approximate effect of certain color filters. In the Color Picker dialog you can see the actual color values for the selected filter. Note that you can also adjust the overall strength of the effect with the Density slider for the Photo Filter adjustment.