Film test: The Seagull Nebula (IC 2177)

During my recent trip to Arizona and California, I ran a comparison test between a few different films. The contestants were:

Film	Type	Exposure time (@ f/4)
Kodak E200 Professional	slide	60 min
Fuji Provia 400F Professional (RHP III)	slide	40 min
Kodak Ektapress PJ 400	negative	40 min
Kodak Supra 400 hypered	negative	40 min

Except for the Supra 400, all films were unhypered. The test exposures were shot with a Vixen R200SS 8" f/4 Newtonian from Alamo Campground at Organ Pipe Cactus National Monument. This is a dark, very dry site with only minimal light pollution from the Mexican town of Sonoyta. All photos were taken on the night of Dec. 26/27, 2002. Unfortunately, tracking was compromised by strong, gusty winds, which explains the less than round stars (particularly in the Provia image). However, the effects on the image of the nebula itself should be negligible.

Raw images

The images were scanned with a Polaroid Sprintscan 35 Plus using the "old" Polaroid software with fixed exposure settings.


Kodak E200 professional	Fuji Provia 400F


Kodak PJ 400	Kodak Supra 400

Processed images

The scanned images were color-corrected and contrast enhanced, mainly by manipulating the 'levels' dialog in The Gimp. No flat-fielding or star-shaping was done. All films exhibit good red sensitivity, with Supra 400 just slightly behind the other three films. However, only the hypered Supra 400 reveals the faint blue reflection nebulosity in the lower right hand corner, confirming the good blue response reported on Don Westergren's film test pages.


Kodak E200 professional	Fuji Provia 400F


Kodak PJ 400	Kodak Supra 400

Graininess

Examining an enlarged portion of IC 2177, it is evident that E200 has by far the lowest graininess, followed by Provia 400F, PJ400 and Supra 400. The high graininess of Supra 400 results from its low contrast in the raw image, since a higher degree stretching had to be used which made the grain much more apprent.


Kodak E200 professional	Fuji Provia 400F


Kodak PJ 400	Kodak Supra 400

Conclusions

All four tested film are good choices for photographing emission nebulae. However, for blue reflection nebulae, Supra 400 is the only option at this time. According to Don Westergren's results, this film gains relatively little from hypering, so the conclusions are likely to be valid for unhypered Supra 400 as well. Kodak has announced to shorten the red sensitivity of Supra 400 in the very near future, so this might be a good time to stock up on it. In term of graininess, E200 is the undisputed winner. A drawback is its lower sensitivity, which requires exposure times at least 50% longer than for the 400 speed films. Also, star images tend to burn out in slide films due to their higher contrast.

Last update: by Axel Mellinger