Saturday, March 1, 2008

Filtering natural light

In terms of film photography, colour film responds to slight changes in the quality of light that the eye doesn't notice. In the digital world, things are a bit different. We can, however, borrow some effects from the old days to help fix our images. We return again to our SUV picture to take a look at yet another plug-in, the Dfx filter suite from Tiffen.

Page 53 of the Book has a colour temperature reference chart that will come in handy in examining this incredible plug-in suite. For our purposes today, I'll expand on the chart by adding the corresponding Kodak Wratten filter reference.

Artificial Light:
2500k-2600k = 80A+80D
2700k = 80D
2900k = 82B
3200k - no filter
3400k = 81A

Natural Light:
3000k-3500k = 80B
3500k-4000k = 80C
4000k-4500k = 80D
4500k-5000k = 82B
5000k-5500k = 82A
5500k - no filter
6000k = 81A
6500k = 81B
7000k = 81C
7500k-8000k = 81EF
16000k = 85

You may recognise the reference numbers from the Photo Filter dialog box. You may also recognise that there are many more filters referenced here than are listed in the dialog box. Not to worry, Dfx has you covered.

The Dfx dialog box is nicely organised. We are interested in Photographic filters and that's just where we'll find them. For the Wratten filters, we'll mainly be concerned with Colour Conversion and Light Balancing filters. The Conversion filters are strong amber (85 series) or strong blue (80 series). The Light Balancing filters are much paler (for example - 81C is useful if your subject is in the shade on a sunny day). But Dfx has many more options than just the Kodak filters.

With just a few clicks, I found the CC50Y Filter (simulates the
Cokin A729 Yellow Cc Filter) in the Color Compensating tab. This filter brought the image very close to where we needed to be. We can further adjust for Quality, Exposure, and the Preservation of the Highlights.

Dfx works as a Smart Filter, so fine tuning is possible. There are several ways to get rid of that left over colour wash - or we can go back to Dfx and try another filter. It's easy enough to navigate and use that we'll have no trouble experimenting.

It's fairly reasonably priced - considering all the filters that come in the complete version. All in all, a very nice tool to help with our mastering colour and light.


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