Sunday, April 28, 2013

Old film scanning

Recently, I've been playing with film as can be seen on flickr and on earlier posts.  Mostly, I've been working with black and white film on medium format.  This has yielding pretty nice results and I've been happy enough with the method of scanning by taking a picture with the DSLR and inverting it.

I wanted to do more with color beyond slide film and get back to my old negatives as well.  The scans provided by the developing process at K&S yields 2000 x 3000 pixel images, not the greatest of resolutions, with a strong grid at the 2 pixel level.  I know that I can get better resolution with my digital camera.

After doing a lot of reading and research, I found a great post online that goes through the various steps needed to correct color when scanning via a digital camera.  As a nice bonus, it provided instructions via Lightroom, which is what I use.

The biggest challenge with color correcting for the orange cast of the negatives is that there's not enough headroom for the proper blue exposure.  Film scanners compensate for this by doing a deeper scan on the cyan and magenta colors, getting better data through the orange cast.  For the one shot color approach, it's easier to apply a color correcting filter and then expose with a white balance based on the unexposed substrate. 

I started the effort with a simple Cokin type A Blue 80A color correcting filter attached to the front of the lens.  What an amazing difference this has made!  Now it's relatively easy to invert the curve and play with the tone levels to get good shots.  I'm very pleased with how this has turned out.

My current setup limits the ability of the camera to get close enough to the 135 film to show it fully filling the APSC sensor, so it's still a trial at this point.  Even so, I'm excited at how it's rendering the first roll of color negative film I've run through the Pentax 67 camera.

Further experiments show that I'll need to overexpose the negatives a bit more -- possibly a full stop more than automatically measured.  This should help make the process of inverting a little easier.